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Universidad del Turabo

DETERMINATION OF TOTAL VOLATILE ORGANIC COMPOUNDS (TVOC) IN ELEMENTARY PUBLIC SCHOOLS OF CAGUAS II DISTRICT IN THE MUNICIPALITY

OF CAGUAS, PUERTO RICO

By

Nadya G Cruz-Martínez BS Natural Science-Industrial Chemistry, University of Puerto Rico at Humacao

THESIS

School of Science and Technology Universidad del Turabo

In partial fulfillment of the requirements for the degree of Master of Environmental Science

Environmental Analysis Specialty

(Chemistry Option)

Gurabo, Puerto Rico

December, 2008

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Universidad del Turabo

A thesis submitted in partial fulfillment of the requirements for the degree of Masters in Environmental Sciences

Determination of Total Volatile Organic Compounds (TVOC) in Elementary Public Schools of Caguas II District in the Municipality of Caguas, Puerto Rico

Nadya G Cruz-Martínez

Approved: ________________________ Cesar Lozano, PhD Research Advisor ________________________ Teresa Lipsett-Ruiz, PhD Member ________________________ Pedro Modesto, PE Member

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© Copyright 2008 Nadya G Cruz-Martínez. All Rights Reserved.

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Dedication

I dedicate this work to my grandmother Carmen María Meléndez-Mateo and to

my grandaunt María Emilia Meléndez-Mateo and to those how could not live to see the

outcome of this research work. They will forever be remembered and are always going

to be next to our hearts. It is to them that I dedicate this thesis.

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Acknowledgments

I wish to thank my mother Daisy Martínez-Meléndez and my sister Valesis T.

Cruz-Martínez for their love and belief in me. They bore me, raised me, supported me,

taught me, and loved me. To Raymond Tirado-Agosto for his love, encouragement,

support, patience, and for contributing interest and help on many occasions.

This work would not have been possible without the support and encouragement

of my extended chosen family, on whose constant encouragement and support I have

relied on.

I would like to acknowledge the help of many people during my study; the

Teachers and Directors of the public schools system of Puerto Rico, to the Department

of Education of Puerto Rico, to my colleagues. To the professors: Teresa Lipsett, Pedro

Modesto and César Lozano for supervising my work, I would like to express thanks,

without every one’s determination and perseverance this work would not have been

possible.

It is a pleasure to thank the many people who made this thesis possible. It is

difficult to overstate my gratitude.

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Table of Contents

page

List of Tables…………………………………………………………………………………….vii

List of Figures…………………………………………………………………………………..viii

List of Appendices…………………………………………………………………….…………x

Abstract…………………………………………………………………………………………...xi

Chapter One. Introduction……………………………………………………………………...1

Section 1.01. Study Area Location…………………………………………………….1

Section 1.02. Volatile Organic Compounds…………………………………………..2

Section 1.03. Air Quality in Elementary Schools and Health Effects…..………….4

Section 1.04. Research Objective……………………………………………..………5

Section 1.05. Research Hypothesis……………………….………………………….5

Section 1.06. Research Justification…….……………………………………………6

Chapter Two. Literature Review……………………………………………………………....8

Section 2.01. Environmental Pollution……………………………………………..…8

Section 2.02. Air Pollution……………………………………………………………...9

Section 2.03. Air Pollutants…………………………………………………………...10

Section 2.04. Air Toxics/Hazardous Pollutants……………………………………..12

Section 2.05. Air Quality………………………………………………………………15

Section 2.06. Indoor Air Quality………………………………………………………16

Section 2.07. Indoor Air Pollutant Problems………………………………………..19

Section 2.08. Volatile Organic Compounds: Concept and Terms………………..20

Section 2.09. Total Volatile Organic Compounds………………………………….23

Section 2.10. Microbial Volatile Organic Compounds……………………………..25

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Table of Contents (continued)

page

Section 2.11. Health Effects of VOC’s………………………………………………27

Section 2.12. VOC Detection Methods……………………………………………...29

Chapter Three. Methodology…………………………………………………………………33

Section 3.01. Introduction…………………………………………………………….33

Section 3.02. Research Design………………………………………………………33

Section 3.03. Population Detection……………………………………………..…...34

Section 3.04. Instrumentation…………………….…….…………………………….35

Section 3.05. Data Recollection Procedure…………………………………………37

Section 3.05.1. Data Recollection Procedure Phase One………………………...38

Section 3.05.2. Data Recollection Procedure Phase Two………………………...40

Section 3.06. Data Analysis…………………………………………………………..41

Chapter Four. Results…………………………………………………………………………43

Section 4.01. Phase One of the Research………………………………………….43

Section 4.01. Phase Two of the Research………………………………………….53

Chapter Five. Discussion, Conclusion and Recommendations…………… ……………..60

Section 5.01. Introduction of Discussion…………………….……………………...60

Section 5.02. Discussion of Phase One of the Research….……………………...61

Section 5.03. Discussion of Phase One of the Research….……………………...68

Section 5.04. Conclusion……………………………………………………………..73

Section 5.05. Recommendations…………………………………………………….75

Literature Cited………………………………………………………………………………….77

Appendices……………………………………………………………………………………...90

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List of Tables

page

Table 4.01. Total of first grade students and first grade personnel in each school studied......................................................................44

Table 4.02. Percentage of first grade students and personnel with respiratory conditions...................................................................45

Table 4.03. Temperature data obtained for each school for indoor and outdoor day samples....................................................................46

Table 4.04. Percentage of relative humidity data obtained for each School for indoor and outdoor day samples.................................46

Table 4.05. Wind velocity obtained for each school for indoor and outdoor samples...........................................................................47

Table 4.06. Summarized indoor and outdoor TVOC results measurements for the schools studied.................................................................48

Table 4.07. Comparison of types of indoor ventilation and TVOC results measurements for the schools studied…………………...49

Table 4.08. Total of fist grade students and personnel and the total percentage with respiratory conditions in the school 004……….54

Table 4.09. Temperature data obtained for the school 004 for indoor and outdoor samples...........................................................................55

Table 4.10. Percentage of relative humidity data obtained for the school 004 for indoor and outdoor samples…………..............................56

Table 4.11. Summarized indoor and outdoor TVOC results measurements for the school 004………………………………………………………59

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List of Figures

page

Figure 4.01. Concentration of TVOC versus time for school 002 for indoor and outdoor TVOC data....................................................50

Figure 4.02. Concentration of TVOC versus time for school 003 for indoor and outdoor TVOC data....................................................51

Figure 4.03. Concentration of TVOC versus time for school 004 for indoor and outdoor TVOC data....................................................52

Figure 4.04. Concentration of TVOC versus time for indoor air measurements for school 004......................................................57

Figure 4.05. Concentration of TVOC versus time for outdoor air measurements for school 004......................................................58

Figure 5.01. Indoor TVOC mean concentrations and maximum peak observed at the schools studied...................................................65

Figure 5.02. Outdoor TVOC mean concentration and maximum peak observed in the schools studied...................................................66

Figure 5.03. Comparison chart for indoor and outdoor TVOC maximum peak measurements for each school studied...............................67

Figure 5.04. Comparison chart for indoor and outdoor TVOC averages for each school studied................................................................68

Figure 5.05. Outdoor TVOC mean concentration and maximum peak observed in the school 004 for the days studied..........................70

Figure 5.06. Indoor TVOC mean concentration and maximum peak observed in the school 004 for the days studied..........................71

Figure 5.07. Comparison chart for indoor and outdoor TVOC averages for school 004...............................................................................72

Figure 5.08. Comparison chart for indoor and outdoor TVOC maximum peaks for school 004....................................................................73

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List of Appendices

page

Appendix One. Caguas, Puerto Rico........................................................91

Appendix Two. Secondary production of urban smog oxidants by photochemical reactions in the atmosphere.....................92

Appendix Three. Asthma prevalence in the year 2000................................93

Appendix Four. Volatile organic compound sources..................................94

Appendix Five. Volatile organic compounds emission by source in 2002..............................................................................95

Appendix Six. Hazardous air pollutants of greatest concern..................99

Appendix Seven. Volatile organic compound emission sources.................100

Appendix Eight. List of elementary public schools Caguas II District.......101

Appendix Nine. Instrumentation used......................................................102

Appendix Ten Volatile organic compounds detected by PID 10.6 eV Lamp………………………………………………….……103

Appendix Eleven Volatile organic compounds not detected by PID………108

Appendix Twelve. Aerial photographs of the schools studied......................109

Appendix Thirteen. Meteorological data of Caguas, Puerto Rico..................113

Appendix Fourteen. Wind Resources of Puerto Rico......................................116

Appendix Fifteen. Potential air quality problems in schools.........................117

Appendix Sixteen. Summarized climatologic day data sample....................122

Appendix Seventeen. Summarized TVOC measurement results data..............126

Appendix Eighteen. Glossary terms...............................................................128

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Abstract

Nadya G Cruz-Martínez. (Masters of Science, Environmental Science)

Determination of Total Volatile Organic Compounds (TVOC) in Elementary Public

Schools of Caguas II District in the Municipality of Caguas, Puerto Rico. (December,

2008)

Abstract of a masters thesis at the Universidad del Turabo.

Thesis supervised by Professor César Lozano.

No. of pages in text 132

The goal of this study was to investigate the total volatile organic compounds

(TVOC) concentration upon indoor and outdoor air quality in randomly selected

elementary public schools of the Caguas II District Municipality of Caguas, Puerto Rico,

and to compare it to those from the literature guidelines since there are no TVOC

guidelines from regulating environmental agencies in the United States nor in Puerto

Rico. Baseline measurements of this research compared to TVOC guidelines from the

scientific literature show that TVOC do not seem to be an on-going problem in

elementary public schools of Caguas II District because for most of the time of sampling

measurements, there were no detectable levels of TVOC that could cause any potential

health problems in children or in school personnel (>25mg/m3). Nevertheless, rural

school 004 of this research had continuous TVOC air detection during every outdoor and

indoor air samples having the same pattern of high TVOC peaks early in the morning at

almost three to four times the TVOC guidelines (>25mg/m3) decaying close to midday.

Indoor emission source could come from early cleaning practices in the classroom and

outdoor emission sources could come from nearby industries or transportation

emissions.

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Chapter One

Introduction

Section 1.01. Area of Study Location

This research investigated the presence of total volatile organic compounds

(TVOC) in elementary public schools in the Municipality of Caguas Puerto Rico. Since

Puerto Rico is an Island having limited land supply, many residential and school areas

are located in close proximity to industrial premises and heavily trafficked areas. The air

quality of schools is therefore directly influenced by nearby industrial activities and traffic

conditions which are factors that contribute to air pollution due to heavily traffic

conditions.

Puerto Rico (PR) is an Island located in the Caribbean Basin. It is the most

eastern island of the Greater Antilles in the Caribbean Sea, approximately a thousand

miles southeast of Florida and just east of the Dominican Republic and west of the U.S.

Virgin Islands. The island is approximately 144.81 kilometers wide in an east-west

direction and 48.27 kilometers wide between the north and south coasts.

Puerto Rico is one of the most densely populated islands in the world; it

accommodates 3,808,610 million people in the 8,897 km2 area of the land (US Census

Bureau 2000) having a human population density of 428.08 person/km2. Weather

conditions do not vary greatly across seasons of the year. The average temperature is

27°C, and humidity averages 77 percent (Loyolo-Berrios et al. 2007).

Puerto Rico is divided in 72 municipalities of which only one Municipality served

as the study area. The Municipality of Caguas, Puerto Rico served as the study area for

this research (see Appendix One). Caguas lies in the fertile Caguas valley, it is located

in the Central Mountain Range, to the south of San Juan (Capital of Puerto Rico) at

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approximately 20 km from the international airport; east of Gurabo and San Lorenzo;

and west of Aguas Buenas, Cidra and Cayey.

Caguas is a city with a territory of 115 km2 (Agricultural Extension Service 2005)

divided in 11 bounds. The downtown area of Caguas is denominated Pueblo, and the

other ten (10) bounds are called Barrios which some of them are suburbs (see Appendix

1). On average, the annual amount of rainfall over the territory of Caguas is 155.93

centimeters, and the average annual temperature is 21.60°C (US Census Bureau 2000).

The United States Census Bureau in the year 2000, estimated a total growing population

of 140,502 with a density of 955.1 person/km2.

Section 1.02. Volatile Organic Compounds

Organic pollutants accounts for the vast majority of pollution found in air. Indoor

air in residences, offices, public access buildings and transportation vehicles often

contain volatile organic compounds (VOC) at levels in order of magnitude higher than

those outdoors (Edwards et al. 2001, Jones 1998) from emitting sources such as

cleaning products, vehicle emissions and electronic appliances. Jones (1998) has found

levels of most VOC can be five (5) to ten (10) times higher indoors than outdoors, and

sometimes indoor levels can be more than 100 times higher than outdoor levels

(American Lung Association 2002).

VOC cover a broad spectrum of chemical classes with different physicochemical

and biological properties with inhalation a prominent route exposure due to their volatility

although many VOC can quite readily be absorbed through the skin (Henrich-Ramm et

al. 2000). VOC are an important group of air pollutant to study as they contribute to two

of the most serious air quality problems (Gee et al. 1998). Firstly, they have been

demonstrated to be active in the formation of photochemical smog and ground level

ozone production (Leikauf 2000) (see Appendix 2). Secondly, several VOCs found in

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the air are accepted carcinogens (1,3-butadiene, benzene, formaldehyde and

acetaldehyde) (Gee et al. 1998).

VOC are released into the atmosphere from both biogenic (mainly vegetation)

and anthropogenic sources (e.g. vehicle emissions, the manufacture and use of

petroleum products, biomass burning, landfills and industrial waste water and sewage

treatment plants) where they undergo various chemical degradation processes (Davis

2001, Herbarth et al. 1997). The most important organic chemical pollutants are found

in the gas phase at typical environmental conditions (Levin 2004). There is also concern

about some VOC gases that can go back and forth from liquid to solid state to the gas

state (Levin 2004). Exposure also depends on the intrinsic physical/chemical properties

of each compound, including vapor pressure and solubility in various media (Leikauf

2000).

The ongoing use of over 50,000 commercial chemical substances continue to

present a mayor challenge to environmental health scientists because each compound

could be considered toxic depending on the magnitude of human exposure, the dose

delivered to target organs, and the biological response (Leikauf 2000). Interminent

exposure to VOC’s in high concentrations can depend on regional meteorology,

atmospheric dispersion, transport and removal (Leikauf 2000). This type of exposure is

difficult to monitor or model. Differences in climate, geography, industrial activity, vehicle

age and fuels used will strongly affect the nature of air pollution in different areas (Gee et

al. 1997). The measurement of individual compounds is necessary to assess the

potential health effects of organic chemicals (Levin 2004). Many investigators report the

total of all VOC measured and report it as TVOC or Total VOC concentration (Levin

2004).

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Section 1.03. Air Quality in Elementary Schools and Health Effects

Indoor air quality in schools can have a substantial impact on children’s health,

as an important environment where children may be exposed to pollutants and allergens

(Zhang et al. 2006). School provides a major indoor environment for children away or

apart from their home. Children may spend 10 hours per day at school, and at least 100

hours per year (Zhang et al. 2006) depending on the time that they arrive at the school

and the time they leave the school.

Primary and secondary education is the largest public enterprise in the United

States, employing over three (3) million teachers and school staff who instruct over 47

million children in 92,012 elementary, middle and high schools in 15,000 districts

(Godwin et al. 2006). Surprisingly, given the magnitude of the school population,

information on indoor air quality (IAQ) in schools is very limited (Daisey et al. 2003). The

understanding of exposures and the association of symptoms and health effects of air

quality remain incomplete. IAQ problems may be exacerbated in schools owing to the

potential sensitivity of occupants, the simple and inexpensive building construction in

most schools, minimal landscaping with poor drainage, basic and minimal engineered

ventilation and if any air conditioning system, the lack of preventative maintenance, and

crowded conditions (Godwin et al. 2006). It has been suggested that exposure to air

pollutants and allergens at school was associated with an increase in prevalence of

respiratory symptoms and asthma (Godwin et al. 2006, Daisey et al. 1994). One of the

reasons is that the amount of pollutant delivered to the lung, depends on the person’s

breathing rate (Weisel 2002), in this case it will depend on children’s breathing rate (0.3

L/min). Children differ from adults in their activities, their rate of breathing, their lung

anatomy and physiology, and their organ maturity (Environment Protection and Heritage

Council 2008). The higher risk to children is a result of their higher metabolic rate,

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higher intake of airborne pollutants and lower resilience, resulting in a two to four times

higher absorption rate (Environment Australia 2001).

Investigations examining IAQ problems in PR schools have been complaint-

driven in response to specific concerns or worker compensation issues, or by legislative

initiatives (Puerto Rico Senate 2005, Cámara de Representantes de Puerto Rico 820

2005, Cámara de Representantes de Puerto Rico 892 2005, Cámara de Representantes

de Puerto Rico 2448 2005). Often in schools a specific pollutant, e.g. asbestos or

bioareosols, or combinations of pollutants are addressed (Godwin et al. 2006).

Therefore, reducing exposure to pollutants and allergens at schools and improving

indoor environmental quality is an important public health issue (Zhang et al. 2006).

These outcomes emphasize the importance of knowledge of VOC in elementary

schools.

Section 1.04. Research Objective

The objective of this study was to investigate the total volatile organic

compounds (TVOC) levels upon indoor and outdoor air quality in a representative

sample of elementary public schools of the Caguas II District Municipality of Caguas,

Puerto Rico. Because most of TVOC levels detected in scientific literature research are

attributed to building material construction such as wood and gypsum board, but building

schools in Puerto Rico are made of concrete.

Section 1.05. Research Hypothesis

The total volatile organic compound (TVOC) levels do not exceed concentration

limits found in the scientific literature guidelines in public elementary schools of the

Caguas II District Municipality of Caguas, Puerto Rico if there is no known emission

source present.

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Section 1.06. Research Justification

In Puerto Rico, given the size of the school population, information on air quality

in schools is not known. This is surprising given the fact that children and infants are

among the most vulnerable in terms of air quality, because their organ systems are still

developing, so they are more easily affected by damage to ongoing developmental and

organogenesis processes (Magas et al. 2007). The evidence suggests that

environmental conditions shape attitudes and eventually performance, especially

attendance (Berry 2008).

There are no published data on the detection in air of TVOC or VOC indoors or

outdoors in schools of Puerto Rico. Nevertheless, the Environmental Quality Board of

Puerto Rico has investigated objectable outdoor odors in schools when the issue has

become a controversy or a health hazard in the school. Their findings however are not

publicly available. Much less is known about TVOC levels indoors and outdoors in

schools and if these levels could cause a potential health concern among school

students and personnel.

The majority of indoor air pollution in the United Stated is attributed to come from

poor ventilation from HVAC systems (Heating, Ventilation and Air Conditioning systems)

and from off gassing building materials made such as gypsum boards and furniture. In

Puerto Rico however, buildings and houses are made of cement and ventilation systems

are by open window and/or air conditioning units. Since Puerto Rico is an Island

situated in the Caribbean Sea, it is susceptible to hurricanes and to minimize destruction

the majority of the construction is made of cement. In view of this fact we can expect

that there would be no indoor detectable levels of TVOC in classrooms if there is no

known VOC source and good ventilation is in place. On the other hand TVOC levels

outdoors in public schools will depend greatly on what is around the area of the school if

there is no known VOC source.

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Air quality has become an issue of major concern in countries worldwide but

whether outdoors or indoors, at work or at home, solvents are being inhaled. Despite

the legislative efforts of the Environmental Protection Agency’s “Clean Air Act”, outdoor

air is far from clean. Ambient air levels of VOC are monitored because of their role in

observed increases in levels of tropospheric (ground-level) ozone and decreases in

levels of stratospheric ozone, and because of their importance relating to adverse

human health effects (Davis 2001). Although VOC emissions are a global problem, their

increased use in developing countries has not been accompanied by effective

monitoring programs. Sampling results from national monitoring programs are used by

regulatory agencies to evaluate human and environmental health effects of VOC, to

assess the effects of photochemical oxidation, to provide input on decision making

processes regarding environmental polices and control strategies related to VOC

emissions (Davis 2001).

Consideration of VOC concentration should be made due to the development of

hundreds of new chemicals every year, released in varying quantities into the

environment, and absorbed into the bodies of many American children (Ladrigan et al.

2004). The majority of these chemicals are not adequately evaluated prior to

commercial introduction for their potential toxicity, their potential effects on development,

or their possible interactive effects with other chemicals (Ladrigan et al. 2004).

Furthermore, the minimum exposure levels necessary for a specific toxic effect are

rarely known and the minimum toxic dose estimates for general population grossly over

estimate the doses that could affect sensitive individuals (Reiser et al. 2002).

In this chapter, the idea of this investigative study has been introduced and

related proceedings of the research initiative have been presented. In the next chapter,

the literature review related to this subject is offered.

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Chapter Two

Literature Review

Section 2.01. Environmental Pollution

The demand caused by the increasing population coupled with the desire of most

people for higher material standard of living are resulting in worldwide pollution on a

massive scale (Manahan 2000). The environment is the combination of all external

conditions and influences relating to the life, development and survival of all living things

(British Colombia Clean Air Committee 2005). Environmental pollution can be divided as

water, air and land pollution (Cunningham et al. 2003), but all three areas are linked.

Frequently, time and place determine what may be called a pollutant. It is difficult to give

a simple, comprehensive definition of what is a pollutant. A reasonable definition of a

pollutant is a substance present in greater than natural concentration as a result of

human activity that has a net detrimental effect upon its environment or upon something

of value in that environment (Manahan 2000, British Colombia Clean Air Committee

2005). In some cases pollution is a clear-cut phenomenon, whereas in others it lies

largely in the eyes of the beholder and can be perceived as a contaminant. A

contaminant is not classified as a pollutant unless they have some detrimental effect or

cause deviations from the normal composition of the environment (Manahan 2000).

We come in contact with a wide variety of air pollutants every day. They are

being released in the environment each day. Of special importance to us are certain

emissions that are having a significant effect on the earth’s atmosphere, leading to

changes in the planet’s delicate balance of life (British Colombia Clean Air Committee

2005). A greater than natural amount of greenhouse gases in the atmosphere are

contributing to global climate change. Greenhouse gases are gases that absorb

atmospheric and solar infrared radiation and reflect it back to earth thus increasing

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global warming (Enzler 2008). Many greenhouse gases occur naturally in the

atmosphere, such as carbon dioxide, methane, water vapor, and nitrous oxide, while

others are synthetic (Enzler 2008, British Colombia Clean Air Committee 2005). Those

greenhouse gases that are man-made include chlorofluorocarbons (CFCs),

hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs), as well as sulfur hexafluoride

(SF6) (Enzler 2008, WG Environment 2004). Past and future anthropogenic emissions

of greenhouse gases (carbon dioxide, methane and nitrous oxide) enhance global

warming (Enzler 2008). This phenomenon is the progressive rise of the earth’s surface

temperature thought to be caused by the enhanced greenhouse effect. Global warming

may be responsible for changes in global climate patterns (British Colombia Clean Air

Committee 2005). Industrialized nations have committed to reduce their contribution of

greenhouse gases to the atmosphere through the Kyoto Protocol (WG Environment

2004). The Kyoto Protocol is a pact agreed on by governments at a United Nations

conference in Kyoto, Japan 1997 to reduce the amount of greenhouse gases emitted by

developed countries by 5.2 percent of 1990 levels during the five-year period 2008-2012.

Section 2.02. Air Pollution

Air pollution is a major problem that has been recognized throughout the world

for hundreds of years. Air pollution is the term used to describe any harmful gases

and/or particles in the air we breathe (Manahan 2000). Pollutants have a distinct

chemical or physical structure or a distinct effect on human health and can form in

various ways (Manahan 2000).

Air pollution is caused by both human and natural sources (Cunningham et al.

2003). Human sources include traffic, agriculture and/or industry. Natural sources

include dust storms, volcanic eruptions and/or emissions from plants. Emissions may be

roughly described as the pollutants that are dumped into the air. According to Godish

(2001) is important to know at least, which pollutants are emitted, how much of each,

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from what kind of source and the source location (see Appendix 4). Air pollution can be

divided in categories according to the source it is derived from. Air pollution sources

may be biological (pollen, small insects and microorganisms [bacteria, fungi, yeasts and

algae]), physical (sound, smell, thermal pollution and radioactive radiation) or chemical

(such as ozone, aerosols and ammonia) (Enzler 2008).

These types of pollution undergo a number of processes. These processes are

(Enzler 2008): emission (contaminants are released into the air), transport (contaminants

are transported to different locations through air), exchange (compounds react with other

compounds in air), distribution (contaminants are distributed in air), immission

(contaminants remain in a certain area), deposition (contaminants are deposited in a

certain area, on the soil or on objects). In the atmosphere these chemicals can react

with other chemicals to form more dangerous substances. The weather plays an

important role in the formation, transformation and/or disappearance of air pollution

(Enzler 2008). This is mainly influenced by wind and temperature. Rain can remove

pollutants from air, causing soil and water pollution (Cunningham et al. 2003). Sunlight

can also aid in the conversion of air pollutants to different substances.

Section 2.03. Air Pollutants

Air pollutants are divided in two classes: primary and secondary pollutants, by

the United States Environmental Protection Agency (EPA). Primary pollutants are those

released directly from the source into the air in a harmful form (Cunningham et al. 2003).

Secondary pollutants are modified into a hazardous form after they enter the air or are

formed by chemical reactions as components of the air mixture and interaction

(Cunningham et al. 2003).

The most common pollutants that affect the air are sulphur dioxide, nitrogen

oxides, volatile organic compounds, carbon monoxide, dust particles, ozone and,

radioactive radiation (Cunningham et al. 2003, Enzler 2008, Manahan 2000).

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Sulphur dioxide (SO2) is mainly emitted during the combustion of sulphur-

containing fossil fuels, such as crude oil and coal. Sulphur dioxide concentrations in air

have decreased in the past two decades, mainly because we use more non-sulphur-

containing fuels for the generation of energy. Sulphur dioxide is a stinging gas and as a

result it can cause breathing problems in humans. In moist environments, sulphur

dioxide may be converted to sulphuric acid. This acid causes acidification and winter

smog.

Nitrogen oxides (NOx) are emitted by traffic and combustion installations, such as

power plants, and industries. Nitrogen oxides are gasses that react with other air

pollutants when they are present in air. For example, nitrogen oxides play an important

role in the formation of ozone in the lower atmosphere, and in acidification and

eutrophication processes. They can deeply penetrate the lungs and damage human

lung functions.

Volatile Organic Compounds (VOC) can be an array of different contaminants,

such as carbohydrates, organic compounds and solvents. These organic compounds

usually derive from petroleum and gasoline reservoirs, industrial processes and fuel

combustion, paint and cleanser use, or agricultural activities. VOC play an important

role in ozone formation in the lower atmospheric layer, the main cause of smog. VOC

can cause various health effects, depending on the kind of compounds that are present

and their concentrations. Effects can vary from smell nuisance to decreases in lung

capacity, and even cancer.

Carbon monoxide (CO) is a gas that exists during the incomplete combustion of

fuels. When we let a car engine run in a closed room, carbon monoxide concentrations

in the air will rise extensively. Carbon monoxide contributes to the greenhouse effect,

smog and acidification. The gas can bind to hemoglobin in blood, preventing oxygen

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transport through the body. This results in oxygen depletion of the heart, brains and

blood vessels, eventually causing death.

Dust particles form a complex of organic compounds and minerals. These can

derive from natural sources, such as volcanoes, or human activities, such as industrial

combustion processes or traffic. Particles are categorized according to their size. The

smallest particles have the ability to transport toxic compounds into the respiratory tract.

Some of these compounds are carcinogenic. The upper respiratory tract stops the

larger dust particles. When they are released into the environment, dust particles can

cause acidification and winter smog.

Ozone (O3) is created through photochemical transfer of oxygen. This process

takes place under the influence of ultra violet sunlight (UV), aided by pollutants in the

outside air. Ozone causes smog and contributes to acidification and climate change.

Ozone is an aggressive gas, which can easily penetrate the respiratory tract. When

humans are exposed to ozone, the consequences may be irritation of the eyes and of

the respiratory tract.

Radioactive radiation and radioactive particles are naturally present in the

environment. During power plant incidents or treatments of nuclear waste from a war

where nuclear weapons have been used, radioactive radiation can enter the air on

account of humans. When humans are exposed to high levels of radioactive radiation,

the chances of serious health effects are very high. Radioactive radiation can cause

genetic alteration in the deoxyribonucleic acid (DNA) structure and can cause cancer.

Section 2.04. Air Toxics/ Hazardous Pollutants

Toxic air pollutants are those pollutants that cause or may cause cancer,

reproductive effects or birth defects (American Lung Association 2002). Examples of

toxic air pollutants include benzene, which is found in gasoline; perchloroethylene, which

is emitted from some dry cleaning facilities; and methylene chloride, which is used as a

13

solvent and paint stripper by a number of industries. Other listed air toxics include

dioxin, asbestos, toluene, cadmium, mercury, chromium and lead compounds (American

Lung Association 2002) (see Appendices 5 and 6). People exposed to toxic air

pollutants at sufficient concentrations may experience damage to the immune system,

neurological, reproductive, developmental and respiratory and other health problems

(American Lung Association 2002).

According with EPA regulations listed under section 112 of the Clean Air Act

(CAA), VOC are known air toxics. Air toxics are known as hazardous air pollutants

(HAPs), which are pollutants that may cause serious health effects or adverse

environmental and ecological effects. With the passage of the 1990 Clan Air Act, the

United Sates EPA has been charged with the task of regulating the source of emission.

The Clean Air Act identifies 188 HAPs, some common ones are perchloroethylene (from

dry cleaners), mercury (from coal combustion), methylene chloride (from consumer

products such as paint strippers), and benzene and 1,3-butadiene (from gasoline) (EPA

2003).

HAPs are emitted to the ambient air from thousands of sources, including large

and small stationary sources, area sources and mobile sources. A stationary source is

any building, structure, facility, or installation subject to regulation which emits or may

emit any air pollution. These sources include power generating plants, landfills,

petroleum facilities, chemical plants, mining operations, cement and glass manufacturing

companies, and many other heavy industrial sources. Pollutants are emitted into the air

from these plants through fossil fuel combustion, chemical processes, and the grinding

or pulverizing of metals for cement, fertilizers, etc. These processes emit a number of

harmful contaminants into the air including sulfur dioxide, nitrogen oxides, carbon

dioxide, synthetic compounds, and particulate matter. Area sources do not individually

produce sufficient emissions to qualify or to be reported as an individual point source,

14

but collectively the emissions from all the small sources of the same type in an area may

be significant and are reported as a category. Mobile sources is a term used to describe

a wide variety of vehicles, engines, and equipment that generate air pollution and that

move, or can be moved, from place to place. On a broad scale, in 1993, 3.7 million tons

of HAPs were emitted, with approximately 41% from mobile sources, 35% from area

sources and 24% from point sources (Weisel 2002). Based on the National Toxic

Inventory database, nationwide air toxics emissions have dropped approximately 23%

between 1990 and 1996 (American Lung Association 2002).

Individual HAPs are present in the environment at significantly lower

concentrations than the criteria pollutants and are often present at higher concentrations

in indoor air than outdoor air (Weisel 2002). The presence of criteria pollutants along

with HAPs in ambient air makes it difficult to distinguish the effects of HAPs from those

of the criteria pollutants or to determine if there is an interactive effect (Weisel 2002).

HAPs can produce nonspecific respiratory responses (Weisel 2002). Thus, the

combined concentrations may need to be considered when evaluating respiratory

exacerbation and not just exposure to individual compounds. It has been known for

more than a decade that exposure to the mixture of VOC present in indoor air which

includes many HAPs such as aromatic and chlorinated organic compounds, can irritate

the mucus membrane in the respiratory tract in both healthy and sensitive individuals

(Weisel 2002, Wang et al. 2006).

EPA does not set health standards for these pollutants; instead, the Clean Air Act

mandates a two phase approach (EPA 2003). In the first phase, EPA establishes

standards for source categories (major sources, and mobile sources). In the second

phase, EPA assesses how well the standards are reducing health and environmental

risks and based on these assessments determines what further actions are necessary to

address any significant remaining, or residual, health or environmental risks.

15

Also, section 313 of the Superfund Amendments and Reauthorization Act

(SARA) has set a requirement for the reporting of toxic chemical releases resulting in an

extensive database of toxic chemical release inventory for VOC’s and other chemicals.

Section 111 of the CAA required EPA to identify categories of new and modified sources

that contribute significantly to air pollution and endanger public health or welfare. After

identifying approximately 60 source categories (e.g., grain elevators, fossil fuel-fired

generators, steam generating units) that are designated by size as well as type of

process, EPA established uniform, national emission standards known as NSPS (New

Source Performance Standard) in 40 CFR 60 (EPA 2003).

There are other federal laws that regulate VOC emissions directly or indirectly

through the Occupational Health and Safety Administration (OSHA) Standards and other

local and state regulations. OSHA has no exposure limits for groups of chemicals that

researchers believe might act synergistically. As a result, the standards do not usually

protect people from the complex mixture of chemicals that might be found in indoor air

since health effects are being seen at levels much lower than the OSHA standards.

Section 2.05. Air Quality

Air quality has become an issue of major concern in countries worldwide and

many are attempting to develop strategies and interventions aimed at improving air

quality (Gee et al. 1998). Air quality is a direct measure of the concentration of the air

we breathe (Godish 2001). Ambient air quality is the condition of the air, it depends not

only on emissions but also on what happens to them after they are released, this is, on

how much they are dispersed by the wind and how they react in the atmosphere (Godish

2001).

Outdoor air pollution is a dynamic system in which the physical and chemical

processes affecting the accumulation of pollutants in the atmosphere are constantly

changing, largely driven by complex meteorology and photochemistry (Mitchell et al.

16

2007). In contrast, indoor air pollution considers only pollution sources strength and

dilution by air exchange (Mitchell et al. 2007). Trivial actions such as walking across

carpets or improperly using cleaning materials can cause airborne hazardous

substances (Brickus et al. 1998). Similarly, operations of laser printers, photo

duplication machines, vacuum cleaners or even toilet flushing are known sources of

indoor air pollution (Brickus et al. 1998). Thus, inadequate ventilation may also result in

accumulation of pollutants.

Poor air quality produces discomfort, decreases concentration and increases

absenteeism (Brickus et al. 1998). Conversely, improved air quality can lead to

improved productivity. Knowledge of the pollutants concentrations both indoor and

outdoors is therefore critical for an evaluation of their potential health effects.

Section 2.06. Indoor Air Quality

Life today is hectic and between jobs, studies, grocery shopping, hopping in and

out of the car and being at home, we spend a total estimate of 90 percent of our time

indoors (Brown 2004, Wu et al. 2007, Housing Leaflet 250 2004, Darlington et al. 2000,

Höppe et al. 1998, Jones 1998, American Lung Association 2002). For infants, the

elderly, persons with chronic diseases and most urban residents, the proportion is

probably higher (American Lung Association 2002). As we spend more time in enclosed

spaces, indoor climate becomes the dominant climate to which we are exposed (Höppe

et al. 1998). Indoor air quality (IAQ) as the name implies, simply refers to the quality of

the air in an enclosed environment: office, house, buildings, school, etc. (NIOSH 1997).

As stated before, if indoor air is in poor quality, it produces discomfort, decreases

concentration and increases absenteeism (Brickus et al. 1998) either in jobs or at

school.

The quality of indoor air in the indoor environment can be altered by a number of

factors: release of VOC from furnishings, floor and wall coverings, and other finishing

17

materials or machinery; inadequate ventilation; poor temperature and humidity control;

re-entrainment of outdoor VOC; and the contamination of indoor environment by

microbes (particularly fungi) (Bayer et al. 2007). Poor indoor air quality may lead to what

is known as the “sick building syndrome” (SBS). The SBS is when at least 20 percent of

the people occupying a building experience symptom of illness for a period of two weeks

or longer, but the source of the symptoms cannot be determined (Bas 2003). This term

is used to describe situations in which building occupants experience acute health and

comfort effects that appear to be linked to time spent in a building. WHO has estimated

that as many as one third of the world’s buildings today can be considered sick (Bas

2003). Building occupants complain of symptoms associated with acute discomfort, e.g.,

headache; eye, nose, or throat irritation; dry cough; dry or itchy skin; dizziness and

nausea; difficulty in concentrating; fatigue; and sensitivity to odors. Most of the

complainants report relief soon after leaving the building.

Since 1985 scientists have known that indoor air is awful compared to outdoor air

if an adequate ventilation system is not in place (Crinnion 2000). In closed spaces the

operational cost of quantity of ventilation has been given higher priority than quality of

ventilation. The result has been more recycling of air, rather than a greater exchange of

indoor air with outdoor air.

Contaminants reach occupant breathing-zones by traveling from the source to

the occupant by various pathways (Levin 2004). Normally, the contaminant travels with

the flow of air. Air moves from areas of high pressure to areas of low pressure (Levin

2004). That is why controlling building air pressure is an integral part of controlling

pollution and enhancing building IAQ performance (Levin 2004). Pressure differences

will control the direction of air motion and the extent of occupant exposure (Levin 2004).

The locations of highest concern are those involving prolonged continuous exposure; i.e.

home, school and workplace (American Lung Association 2002).

18

Contaminants can come from a variety of sources and by an assortment of

pathways. The majority of indoor air pollutants can come from the building itself, its

contents, or its occupants and their activities (Levin 2004, Liccardi et al. 2001) (see

Appendix 7). Pollutants found in indoor air are often several times higher than outdoors,

and since people spend the majority of time indoors (Levin 2004, Reiser et al. 2002,

Cheng-Lee et al. 2002, Ten-Brinke et al. 1998, Rehwagen et al. 1998); it is important to

recognize and control indoor air pollution.

During the last decade, there has been a significant increase in public concern

about IAQ (NIOSH 1997). The indoor environment has been recognized as a major

source of exposure to allergens and toxic chemicals (Jones 1998). While indoor air

quality is an important concern to the United States Environmental Protection Agency

(EPA), the ramifications of indoor air pollutants in the workplace has made indoor air a

concern of the National Institute for Occupational Safety and Health (NIOSH), the

Occupational Safety and Health Administration (OSHA), the Consumer Product Safety

Commission, (CPSC), the Department of Energy (DOE), the General Services

Administration (GSA), the Department of Transportation (DOT) and the Centers for

Disease Control (CDC). State and local governments often follow the lead of these

agencies with indoor air quality legislation and ordinances (CCIM Institute 2006). Some

known and postulated adverse health effects associated with poor indoor air quality are

allergies, asthma, infections, hypersensitivity pneumonitis, inhalation fevers, mucosal

irritation central nervous system effects (including depression), dermatitis and even

some forms of cancer (Wu et al. 2007).

As indicated above, exposure to allergens and toxins is thought to exacerbate

respiratory conditions, in particular, asthma (Magas et al. 2007, McConnell et al. 2006,

Selgrade et al. 2006, Richardson et al. 2005, Kheradmand et al. 2002, Nicolai 2002,

Liccardi et al. 2001, Kimber 1998, Jones 1998). Asthma is a respiratory disease

19

involving inflammation of the airways and reversible symptoms of bronchospasm

(Richardson et al. 2005). National data shows increases in prevalence of asthma in all

ages, race and ethnic groups and among both adults and children (Magas et al. 2007,

Redd 2002). As the number of cases of asthma was increasing so was the number of

persons dying from asthma (Redd 2002). Children and infants are among the most

vulnerable because their organ systems are still developing, so they are more easily

affected by damage to developmental and organogenesis processes (Magas et al.

2007). Several studies have determined that the estimated direct and indirect costs of

this disease are to be $6.2 billion (Salgrade et al. 2006, Redd 2002, Weisel 2002).

People with pre-existing respiratory conditions are more susceptible to the

adverse effects of air pollution (Magas et al. 2007). In other words, environmental

pollutants may affect allergic sensitization (Kimber 1998). This makes sense do to the

given amount of time that most individuals spend indoors. It seems that the indoor

environment may have an important role to play in allergic disorders (Jones 1998).

Section 2.07. Indoor Air Pollutant Problems

Advances in construction, technology and other transformations have

undoubtedly led to more comfortable living conditions resulting in warmer, more humid

houses with poorer availability to fresh air (Jones 1998). During the 1970’s, ventilation

requirements were changed to conserve fossil fuels and virtually air-tight buildings

emerged (NIOSH 1997). New building methods emphasized a reduction in incidental

exchange of inside and outside air so the internal climate would not diffuse, and

therefore less energy would be needed to maintain temperature (Crinnion 2000). These

conditions provide an environment in which airborne contaminants are readily produced

and build up to much higher concentrations than typically encountered outside (Jones

1998). Inadequate ventilation can increase indoor pollutant levels by not bringing in

enough outdoor air to dilute emissions from indoor sources and by not carrying indoor air

20

pollutants out, allowing concentrations to built up (American Lung Association 2002).

High temperature and humidity levels can also increase concentrations of some

pollutants (American Lung Association 2002). Concern over indoor air has now risen to

such extent that the United Stated Center of Disease Control (CDC) has classified

indoor air pollution as a factor of high environmental risk (Jones 1998; CDC 1994).

There are various common sources of indoor air pollutants (AERIAS 2007). The

National Institute for Occupational Safety and Health (OSHA) investigators have found

IAQ problems caused by ventilation system deficiencies, overcrowding off-gassing from

materials in the office and mechanical equipment, tobacco smoke, microbiological

contamination and outside air pollutants (NIOSH 1997). Some of these pollutant

sources are moisture (can come from showers, clothes washing, cooking, dishwashers,

humidifiers and/or flood damage), gases from building material (paint, carpet,

furnishings, paneling, textiles, insulation, fiber glass), office machines

(copying/duplicating machines, computers, laser printers), cigarette, pipe and cigar

smoke (Ministry of National Health and Welfare 1995). Other sources can be common

chemicals, such as, pesticides, automotive products, cleaning products, personal care

products. Some everyday uses of gas/wood burning appliances (gas stoves, dryers,

and space heaters), fireplaces or everyday activities can become sources of air pollution

(Wolkoff 2003, Edwards et al. 2001, British Colombia Clean Air Committee 2005).

Section 2.08. Volatile Organic Compounds Concept and Terms

To understand what volatile organic compounds are, we must first understand

each term. The term “Organic Compounds” covers all chemical containing carbon and

hydrogen (Ministry of National Health and Welfare 1995). "Volatile" is a term meaning

that these chemicals evaporate, or get into the air easily at room temperature (Manahan

2000). The high volatile property is why these compounds are an air quality concern.

"Organic" is another chemical term meaning that these types of chemicals contain

21

carbon (Manahan 2000). Since carbon burns, many of these chemicals, including

organic solvents, are flammable (Wang et al. 1996, AERIAS 2007).

VOC are those organic compounds that have boiling points roughly in the range

of 50-250°C (Ministry of National Health and Welfare 1995, Herbarth et al. 1997). There

are probably several thousand chemicals, synthetic and natural, that can be called VOC

(Ministry of National Health and Welfare 1995). There is no universally accepted

consensus as to what constitutes a VOC (Davis 2001).

VOC are chemicals that evaporate easily at room temperature (Minnesota

Department of Health 2005). Many products emit “off-gas” VOCs. Some examples of

VOC emissions sources are: paints, varnishes, moth balls, solvents, gasoline,

newspaper, cooking, cleaning chemicals, vinyl floors, carpets, photocopying, upholstery

fabrics, adhesives, sealing caulks, cosmetics, air fresheners, fuel oil, vehicle exhaust,

pressed wood furniture, environmental tobacco smoke (second hand smoke) (Minnesota

Department of Health 2005).

Numerous investigations concerning the quality of indoor air have been carried

out, resulting so far in the identification of more than three hundred VOC in non-industrial

indoor air (Hong et al. 2001). No standards have been set for VOCs in non-industrial

settings. However, VOC’s can be released from products while in use and to some

degree while they are in storage. Example, substances associated with combustion,

liquid-process printers or copiers (Edwards et al. 2001, Cheng-Lee et al. 2002).

However, the amounts given off tend to decrease as the product ages and dries out

(British Colombia Clean Air Committee 2005). In addition, these compounds differ

substantially in their effective atmosphere half-lives (Herbarth et al. 1997). They also

play an important role as essential constituents of the photochemical oxidation

processes, and thus are precursors of smog (Herbarth et al. 1997, Davis 2001).

22

The health effects of VOC can vary greatly according to the compound, which

can range from being highly toxic to having no known health effects. The health effects

of VOC will depend on the nature of the VOC, the level of exposure, and length of

exposure (DEC 2008). VOC include a variety of chemicals that can cause eye, nose,

and throat irritation, headache, nausea, dizziness and skin problems (British Colombia

Clean Air Committee 2005). Higher concentrations may cause irritation of the lungs, as

well as damage to the liver, kidney and/or the central nervous system (British Colombia

Clean Air Committee 2005). VOCs primarily act in the body as both peripheral and

central nervous system neurotoxins (Crinnion 2000). When the central nervous system

is primarily affected the symptoms can include diminished cognition, memory, reaction

time, and hand-eye and foot-eye coordination, and balance and gait disturbances

(Crinnion 2000). Peripheral neurotoxicity usually results in paresthesias, tremors and

diminished fine and gross motor movements. VOCs have been associated with

immunological problems, including increased cancer rates and inmunotoxicity (Reiser

2002, Crinnion 2000). Some VOC are suspected to cause cancer in humans and have

been known to cause cancer in animals (Brickus et al. 1998). The health effects of VOC

depend on the level and length of exposure.

The US Environmental Protection Agency Total Exposure Assessment

Methodology (TEAM) studies have found indoor VOC levels that were two (2) to five (5)

times higher than outdoors (Minnesota Department of Health 2005). VOC have many

sources in the environment. Data on airborne VOC in urban and rural areas in the US

have been reviewed and VOC are found in the air of most urban areas (Sweet et al.

1992). Major anthropogenic sources of VOC in urban areas include the use of solvents,

and gas leakage from natural gas and liquefied petroleum gas (Na et al. 2001).

Unfortunately, they are difficult and expensive to measure. Their importance is related

to the remarkable increase in new materials and new processes (Grimsrud 2004).

23

Section 2.09. Total Volatile Organic Compounds

Identification of individual VOC are expensive and time consuming, and

invariably the total is underestimated because the VOC present at very low

concentrations are difficult to identify or measure (Ministry of National Health and

Welfare 1995). The difficulty in understanding the large numbers of VOC led

researchers to the concept of TVOC (Grimsrud 2004). Measurements of TVOC record

TVOC present without distinguishing different chemicals (Ministry of National Health and

Welfare 1995). In fact, a sample may be dominated by one, innocuous organic chemical

and have a very high value or may have one very toxic chemical along with few others at

low concentration resulting in a very low TVOC concentration (Levin 2004).

Regarding health, evaluating the effects of single compounds may not always be

adequate. The transport of chemicals via migration in environmental media occurs

frequently, sometimes with adverse environmental and human health consequences

(Moseley et al. 1992). Only two percent (2%) of at least 60,000 chemicals that are

widely used have been comprehensively studied for toxic effects and of these, they have

rarely been studied in combined exposure, which actually exists in the real world (Reiser

et al. 2002). Most studies to date have been conducted on single chemicals but less in

known about health effects of combined chemical exposure.

VOC measurement concept does not include the possibility for interactions

between the many compounds in indoor air and no toxicological arguments for exclusion

of some and inclusion of other toxicologically relevant organic vapors and gasses

(Mølhave 2003). In addition it must be remembered that different VOCs have different

toxicity and there is no true standardization procedure for TVOC measures (Mølhave

2003). The TVOC level in a building or home is a good indicator of whether or not there

are elevated levels of VOC. There are often dozens, and sometimes hundreds, of

individual compounds present at concentrations of 1µg/m3 or more (Michaels

24

Engineering 2004). The TVOC indicator can be used in relation to exposure

characterization and sources identification but for VOC only (Mølhave 2003).

One of the reasons TVOC is used is due to interpretation. One single parameter

is simpler and faster than the interpretation of the concentrations of several dozens of

VOC typically detected indoors (European Collaborative Action 1997). In addition,

editors of scientific journals tend to avoid printing long lists of compounds (European

Collaborative Action 1997).

Objections to the TVOC concept began to develop when people noted that many

organic compounds are strong irritants at very small concentrations while others are

quite benign at much larger concentrations. Two significant papers in 1997, Andersson

et al. (1997) and Mølhave et al. (1997), have caused the concept to change from

important guidance about VOC in a space to become, at most, a recommended

procedure for pre-screening a space to indicate a potential problem (Grimsrud 2004).

This concept has led to general guidance about TVOC that can be found in

several sources (Grimsrud 2004). Data in the published technical literature provide the

following guidance in the interpretation of VOC air sampling results. This guidance

includes the following:

a) TVOC concentrations in non-compliant buildings are typically in the range of 200-

500µg/m3 (AQS 1995).

b) Recently renovated spaces may have TVOC levels of up to 30,000µg/m3

(30mg/m3). With adequate ventilation, these levels can decrease to below

1000µg/m3 within a 30-day period (AQS 1995).

c) Based on an extensive literature review, analysis of health related data and a

survey of unpublished measurements, means concentration of individual VOC in

established buildings were generally found to be less than 50µg/m3, with most

below 5µg/m3 (Brown 1994).

25

d) Mean TVOC concentrations in established public buildings were found to be in

the range of 70-410µg/m3 (Brown 1997).

In the literature we can find that TVOC concentration typically range from 50-

1000 µg/m3 over long periods of time and can reach hundreds of mg/m3 for periods of

minutes and hours (European Collaborative Action 1997, Daisey et al. 2003). The low,

long-term concentrations result from the presence of a wide variety of synthetic and

natural products, and from people and their activities (Reiser et al. 2002). The high,

short-term concentrations are most commonly reached during building construction or

renovation, and when certain personal care products, hobby materials or cleaning

agents are used (Reiser et al. 2002). The Indoor Air Goal concentrations recommended

in 1992 by the National Health and Medical Research Council (Australia) were 500

µg/m3

for total VOCs and 250 µg/m3

for any single VOC, both defined by a one-hour

averaging period (Brown 1997).

Researchers have shown that there are signs of irritation and discomfort when

the concentration of TVOC exceeds 3 mg/m3 (Grimsrud 2004, AERIAS 2007) and no

effects when TVOC level is less than 0.2 mg/m3 (Bush et al. 2006, AERIAS 2007).

Significant discomfort and headaches are likely if concentrations fall in the range of 3

mg/m3 – 25 mg/m3; while above 25 mg/m3 exposures may cause significant neurotoxic

effects (Grimsrud 2004, AERIAS 2007). However, this measurement cannot be used as

an indicator of potential heath effects since the content and proportions of the mixture of

VOC can vary greatly from one sample to another (Levin 2004).

Section 2.10. Microbial Volatile Organic Compounds

Nevertheless, not just man-made materials produce VOCs. Some molds and

fungi can give off VOC gases known as microbial VOCs (MVOC) (Schleibinger et al.

2005, AERIAS 2007). These MVOCs are responsible for the characteristic odors

26

produced by molds characterized as "musty, earthy, and moldy" (Ministry of National

Health and Wealfare 1995, Abott 2002). Microbial VOCs are unique and include certain

aldehydes, alcohols, and ketones that are not typically found to emit from building

materials (Schleibinger et al. 2005, AERIAS 2007). Other MVOC are esters, carboxylic

acids, lactones, terpenes, sulfur and nitrogen compounds, and aliphatic and aromatic

hydrocarbons (Bush et al. 2006).

Toxic mold is a term that generally refers only to those molds capable of

producing mycotoxins (Davis 2001). Mycotoxins are natural organic compounds that are

capable of initiating a toxic response to vertebrates (Davis 2001). Over 100 species of

molds found indoors are capable of producing mycotoxins (Vasselli 2005). Mycotoxins

are low-molecular-weight chemicals produced by molds that are secondary metabolites

unnecessary for the primary growth and reproduction of the organisms (Bush et al.

2006). Mycotoxins are not cumulative toxins, having half-lives ranging from hours to

days depending on the specific mycotoxins (Bush et al. 2006). Molds know to potentially

produce mycotoxins and which have been isolated in infestations causing adverse

effects include certain species of Acremonium, Alternaria, Aspergillus, Chaetomium,

Cladosporium, Fusarium, Paecilomyces, Penicillium, Stachybotrys, and Trichoderma

(Bush et al. 2006). This list is not all –inclusive.

The conditions under which dangerous mycotoxins will be produced are not well

understood (Vasselli 2005). Most molds found in indoor air are saprotrophic, meaning

they gather their food from dead moist organic matter such as wood, paper, paint, fabric,

plant soil, dust and cooked or raw foods (Davis 2001). Molds have been found growing

in private homes, office buildings, schools, automobiles, and other locations where

organic matter and water are left unattended (Davis 2001). Floods, leaking pipes,

leaking windows, leaking roofs are all potential sources of moisture that can lead to mold

infestation (Davis 2001). Increased ambient humidity as a result of inadequate

27

ventilation or improper drying of flooded areas can also lead to mold growth (Davis

2001). The key to limiting mold exposure is to prevent the germination and growth of

mold (Davis 2001). Molds grow by gaining nutrients they need through the

decomposition of organic matter (Davis 2001). The introduction of mycotoxins into the

living space can be driven by “sporadic” events associated with: changes in environment

associated with elimination/reduction in moisture source; unplanned air path creation

due to indoor/outdoor pressure variations, mechanical disturbances, etc (Vasselli 2005).

By the inhalation path, mycotoxins have been shown to be 10 to 40 times more toxic

then by ingestion in both animals and humans (Vasselli 2005).

Molds are necessary to plant, animal and human life (Davis 2001). Molds are the

most typical form of fungus found on earth comprising approximately 25% of the earth

biomas (Davis 2001). There are also essential components of our planet’s ecosystem

providing decomposition of many organic substances (Davis 2001). However, it is also

the case that excessive exposure to molds has been a health issue for humans for

many, many years. Molds have been implicated as in a variety of health effects in

humans ranging from minor allergic reactions and exacerbation of asthma, to brain

damage.

Molds cause adverse human health effects through three (3) specific

mechanisms: generation of a harmful immune response (e.g., allergy or hypersensitivity

pneumonitis [HP]), direct infection by the organism and toxic-irritant effects from mold

byproducts (Bush et al. 2006). The Occupational Health and Safety Administration

defines an irritant as a material causing ‘‘a reversible inflammatory effect on living tissue

by chemical action at the site of contact” (Bush et al. 2006).

Section 2.11. Health Effects Of VOC’s

Human exposure to air toxics occurs when individuals breathe air containing

these constituents (Weisel 2002). The concentrations of air toxics vary with time and

28

location, and as people move from locations and activities, the resultant exposure

changes (Weisel 2002). Identification of sources of potentially harmful compounds in

different microenvironments provides the only mechanism of reducing levels of these

compounds in each microenvironment and ultimately leading to cost effective reduction

in population exposures (Edwards et al. 2001). More importantly it allows us to prioritize

those sources that contribute most significantly to exposures and target subpopulations

with elevated exposure levels.

It is generally assumed that indoor air pollution, one way or another, causes an

increase of indoor complaints, e.g. eye and airway irritation and odor annoyance

(Schleibinger et al. 2005, Reiser et al. 2002, British Colombia Clean Air Committee

2005). Air pollution can decrease lung function, increase emergency room visits for

asthma, increase hospitalizations for respiratory diseases, and increase mortality (Chen

et al. 2000). People with respiratory conditions are clearly are at an increased risk from

the adverse effects of air pollution (Leikauf 2000) and children’s health can also be

affected by air pollution (Chen et al. 2000). Poor indoor air quality can be a significant

health, environment and economic problem, and has become a public health issue and

liability from employers and building managers who fail to provide a ‘safe’ work

environment (Brown 2004). Indoor air levels of VOC are closely associated with

increased rates of asthma (Kheradmand et al. 2002, Pachter et al. 2002, Kimber 1998)

and chronic bronchitis, especially in children (Leikauf 2000).

Estimates of the average rates of asthma prevalence increased over time across

all age groups, and asthma mortality also increased (Ladrigan et al. 2004). Various

asthma studies arranged in the United States of America indicate that among Hispanic

cultures, Puerto Rican heritage had the highest rates of asthma and had the highest

asthma mortality rates among Hispanics (Perez-Perdomo et al. 2003, Homa et al. 2000,

29

Findley et al. 2003, Lara et al. 1999, Pachter et al. 2002, Smith et al. 2005, Rose et al.

2006, Ledogar et al. 2000).

The Behavioral Risk Factor Surveillance System (BRFSS) of Puerto Rico which

is an ongoing, state-based surveillance system that collects monthly information about

modifiable risk factors for chronic diseases and other leading causes of death, stated in

2002 that Puerto Rico had a substantially higher than the median asthma prevalence

compared with the United States and its territories (Perez-Perdomo et al. 2003) (see

Appendix 3). Indeed, PR also had the highest asthma prevalence reported during the

year 2000 (Perez-Perdomo et al. 2003). Nearly half of the asthmatic people reported

having children with asthma, and less than one third of non-asthmatics reported having

children with asthma (Perez-Perdomo et al. 2003). From 1980 to1996, the number of

Americans with asthma had doubled to almost 15 million, with children younger than five

(5) years of age, experiencing the highest rate of increase (Perez-Perdomo et al. 2003).

More than ten (10) million school days are lost because of asthma each year (Perez-

Perdomo et al. 2003) accounting for the leading cost of school absenteeism each year

(Air Quality Sciences 2007). Moreover, the disease kills more than 5,000 Americans

and results in half a million hospitalizations every year (Perez-Perdomo et al. 2003).

Section 2.12. TVOC and VOC Detection Methods

Direct-reading tubes

Direct-reading tubes contain chemicals that react with certain individual

VOCs to produce a color change. A fixed volume of air is drawn through the tube

by means of a hand pump. The length of stain observed is proportional to the

volume of air sampled and the concentration of VOCs. The method was

developed for the industrial environment and is only marginally suitable for use in

the office environment because of the much lower VOC concentrations usually

30

found there. The method may, however, be useful for screening purposes.

Sensitivities are in the parts per million range.

Passive badges

Passive organic vapour samplers are available with sensitivity levels in

the range of sub-parts per million. These samplers employ charcoal or another

medium as an adsorbent and use sampling periods of eight (8) hours to one (1)

week. The sampler is sent to a laboratory for analysis and provides average

concentration.

Canisters

A sampler consisting of a prefilter, pump, flow controller, and/or flow

restrictor, may be added advantage of container sampling over sorbent methods

which include: (1) whole-air sampling; (2) no breakthrough of target compounds;

(3) no thermal or solvent desorption necessary; (4) multiple aliquots for replicate

analysis, and; (5) time-integrated samples can be obtained by using controlled-

flow pumps with bags or metal containers. The principle disadvantages of using

canisters are the high initial cost and complex analytical techniques.

Active sorption/chemical analysis

Active sorption methods employ tubes packed with a sorbent that traps

the VOCs when air is pumped through the tubes. Sorbents include organic

polymer resins, such as Tenax, XAD, or activated charcoal. The analysis yields

information on the type and quantity of chemicals present.

A wide variety of organic and inorganic sorbents are available for the

collection of ambient VOCs. Inorganic sorbents are rapidly deactivated by water,

making them unsuitable for use in humid environments. Activated charcoal is

widely used by industrial hygienists. The microporous structure of activated

carbon leads to difficulty in recovering some nonpolar compounds. The

31

advantages over charcoal of the newer sorbent materials include higher

sensitivity, absence of a solvent peak and a reduced effect of humidity on

retention volumes

Flame ionization detectors

In the flame ionization detector (FID) method of measuring TVOC,

chemicals in air are burned to produce ionized products that generate a current

in proportion to the concentration. The ionization process is non-specific, and the

result is displayed in real time. Like photoionization detectors, FIDs are useful for

qualitative survey work, such as source location during a walkthrough and the

identification of sampling points. The variability in response is much less for the

FID than for the PID. Also, a greater number of VOCs are detected by the FID

method. Several instruments combine a FID for screening with a portable gas

chromatography (GC) unit for more detailed analysis and specific compound

quantization.

Infrared detectors

Infrared detectors are direct-reading instruments suitable for monitoring

individual VOCs. The variable-wavelength models can be adjusted to scan for

several different VOCs. The sensitivity is in the parts per million and sub-parts

per million range but is not as good as that of a GC, and there can be a problem

with interferences when several VOCs are present together. Direct-reading

instruments such as PID, FID, and infrared detectors can be operated over

several hours or several days with chart recorders and external or internal data

loggers to yield concentration profiles over time.

Photoionization detectors

Photoionization detectors (PIDs) are direct-reading instruments that

detect airborne chemicals by first breaking them into electrically charged

32

fragments by means of an ultraviolet (UV) lamp, then detecting the fragments

(ions) on a metal screen. The number of VOCs that can be detected increases

as the lamp’s UV energy increases. Note that identification of the individual

chemicals present is not possible.

In this chapter, the literature review of the study has been presented. Scientific

books, professional scientific published literature, and scientific electronic pages were

searched and consulted. In the next chapter, the methodology and the research

procedure for this investigation will be presented.

33

Chapter Three

Methodology

Section 3.01. Introduction

The purpose of this research was to investigate the TVOC concentration levels

from indoor and outdoor air in elementary public schools of Puerto Rico. The intention

from these exploratory findings was to determine if there were detectable limits of TVOC

and if these levels exceed the scientific literature guidelines resulting in poor air quality

that may cause health problems to students and school personnel. The aim of this

research is to serve as a base study for other investigations and monitoring programs

regarding the detection and the comparison of TVOC levels indoors and outdoors in

schools of Puerto Rico since these investigations have not been done before.

Section 3.02. Research design

The study design of this research was constructed with a quantitative focus. A

quantitative study uses data collection to test a hypothesis with numeric measurement

and a statistical analysis (Hernandez et al. 2006). This air quality lead study consists of

researching TVOC levels in the air indoors (regulated by Occupational Safety and Health

Administration (OSHA)) and outdoors (regulated by the Environmental Protection

Agency (EPA) and by the Environmental Quality Board (EQB) of Puerto Rico) of the

school, a topic which has not been studied in public schools of Puerto Rico and compare

them with the literature guidelines since neither OSHA, nor the EPA nor the EQB of

Puerto Rico do not have TVOC air guidelines.

The Municipality of Caguas was chosen for the study for various reasons. Firstly,

Caguas is one of the cities in Puerto Rico that has a high incidence of asthma and other

respiratory diseases (Ramo 2003). Also, this Municipality was chosen because the US

EPA Air Emission Source data indicates that in the year 2002, Caguas was among the

33

34

highest municipalities in Puerto Rico with high VOC air emissions (see Appendix 5).

Since the Municipality of Caguas is a valley it can be susceptible to a phenomenon

called thermal inversion. Thermal inversion occurs when a layer of warm air settles over

a layer of cooler air that lies near the ground. The warm air holds down the cool air and

prevents pollutants from rising and scattering (Cork Harbour Alliance for a Safe

Environment 2008). In other words, it is a weather condition in which cool air is trapped

close to the ground instead of rising (EPA 2002b). When atmospheric thermal inversion

occurs, gases and particles precipitate together with the humidity of air, reaching great

concentrations, therefore, what before could be a dispersed with the wind, will remain

deposited (Ruschi 2007).

Educational Public Schools were chosen for TVOC air determination because as

stated in chapter one, school provides a major environment for children away or apart

from their home and children are among the most vulnerable in terms of exposure to

pollutants in air. Children and adults breath the same amount of air (0.3 L/min), but

children face even greater environmental risks than adults due to the fact that their

immune systems are still developing, and because they have a lower body weight, thus

breathing a relative greater volume of air as compared with adults (AQS 2008). This

results in a higher body burden of air pollutants than that obtained by adults for the same

exposure concentration of pollutants. This is magnified to a larger degree for those

children who suffer from asthma and are spending a significant amount of time indoors

(AQS 2008).

Section 3.03. Population selection

The schools in this municipality are divided in two districts: Caguas I and Caguas

II, by the Department of Education of Puerto Rico. The district in this study was selected

at random resulting in the Caguas II District. This District has a total of eleven (11)

schools (see Appendix 8). Of Caguas II District, a total of six (6) are rural schools

35

representing a 54.5% of all Caguas II District, and five (5) are urban schools

representing a 45.5% of all Caguas II District. All urban and all rural schools in this

District have common surroundings. All rural schools in this district are situated in front

or next to a main road, they all have vegetation and they all are next to urbanizations.

All urban schools are situated in the inner-city next or closed to traffic areas and main

roads. A representative random sample of rural and urban schools was obtained to

conduct the study. The representative samples of urban and rural elementary public

schools constituted of 33% and 40% respectively of total schools of the District. Of

these schools, the first grade classroom was randomly selected for the study to uniform

school grade variables of the research in all the schools.

The inclusion compliance requirements to be able to participate in this research

were: the school had to be in the public school system of Puerto Rico, it had to be an

elementary public school of Caguas II District in the Municipality of Caguas Puerto Rico,

and the school had to have a first grade classroom.

Section 3.04. Instrumentation

Wind velocity was taken using a digital anemometer specifically a Mini Thermo-

Anemometer Model 45158 form Extech® Instruments (accuracy +/- 3%). The

temperature and relative humidity were taken using Q-Trak® Plus Model 8552 IAQ

Monitor. The temperature measurements were registered by the instrument with a

thermistor sensor with a range of 0 to 50°C (±0.6°C) with a resolution of 0.1°C. The

relative humidity measurements were registered by the instrument by a thin-film

capacitive sensor with a range of 5 to 95% (± 3%) with a resolution of 0.1%.

TVOC air measurements were taken using a photoionization detector which has

been used in other air quality investigations (Coel-Roaback 2004, Wilson et al. 2007,

U.S. Department of Health and Human Services 2005, Massachusetts Department of

Public Health 2005, Okoroanyanwu et al. 2004, Anderson et al. 2002, New Jersey State

36

Department of Environmental Protection 1999, The City of New York Department of

Health and Mental Hygiene 2003, The Minnesota Department of Health 2004). The

photoionization detector used (PID) was a PID Monitor model PGM-7240 MiniRae®

2000 from RAE Systems Inc (accuracy +/- 10% of reading) (see Appendix 9). Screening

for TVOC was conducted with a photoionization detector (10.6 eV lamp) which is the

lamp that most VOC ionize (see Appendix 10 and 11), which was calibrated (Isobutylene

Gas Calibration) each day prior to use. Peak and steady readings were recorded every

five seconds.

According to the manufacturer, the MiniRae® 2000 is a Photoionization Detector

with standard 10.6 eV or optional 9.8 or 11.7 eV UV lamp. The MiniRae® 2000 is a

durable, lightweight (19.5 oz., including the battery pack), handheld detector designed

for continuous monitoring of dangerous environments for VOCs at ppb levels. Alarm

levels can be preset for low, high, short-term exposure limit (STEL), and the time

weighed average (TWA) levels. There is an audible alarm as well as a visual flashing

red LED, along with the direct ppb display readout. The detector also has point data

logging capability for post event downloading to a personal computer.

The MiniRae® 2000 uses a dual channel PID and an electrodeless discharge

ultra-violet (UV) lamp as the high-energy photon source. The built-in sample pump

draws in the vapor sample at a nominal flow rate of 400 cc / min. The sample passes by

the UV lamp where it is photoionized enabling the electrons to be detected as current by

the photo-multiplier sensor. The instrument uses the sensor readings to calculate the

gas concentrations based on a known response factor derived from a referenced

calibration gas. The MiniRae® 2000 was evaluated in its “Hygiene” mode where the

monitor runs continuously and the LCD displays instantaneous readings. The

instrument can operate on four AA batteries or the rechargeable Nickel Metal Hydride

37

battery pack. The unit has a built-in battery-charging feature that can operate the

instrument and recharge the battery pack using 110V AC.

Calibration instructions were followed according to the MiniRae® 2000 Operation

and Maintenance Manual. Calibration allows the detector to display the detected sample

concentration in parts per billion (ppb) units equivalent to a 10,000 ppb isobutylene

calibration (span) gas. The startup procedure takes approximately five minutes and the

instrument was allowed to stabilize before the calibration. The calibration procedure

requires setting the detector baseline zero point by challenging the unit with either zero

air or the conditioned air of the agent generation system. Then the detector is

challenged with the calibration gas to set the sensitivity span of the instrument. This

means setting the instrument to read 10,000 ppb when challenged with the 10,000 ppb

isobutylene. Once this is set, the instrument is ready for use.

Section 3.05. Data collection procedure

In order to conduct this research in Caguas II District of the Municipality of

Caguas Puerto Rico, it was necessary to obtain authorization from the Department of

Education of Puerto Rico. This authorization was granted in January 28, 2008, by the

Secretary of Educational Planning and Development of Puerto Rico’s Department of

Education. As part of the compliance, an agreement was established with the

Department of Education, that the participating schools names will be kept anonymous

during the research.

As part of the requirement of the School of Science and Technology of the

Universidad del Turabo, the Institutional Review Board (IRB) and Health Insurance

Portability and Accountability Act (HIPAA) Certifications were obtained. The Compliance

Office of the Universidad del Turabo, after reviewing the research proposal, indicated

that it was not necessary to go through the approval from the Protection Board of Human

38

Beings in Research. After completing the research requirements it was proceeded to

initiate the data collection procedure.

Once the grade was selected at random as the first grade, the total of

representative first grade classroom was studied which constituted at one of the first

grade classrooms in each school studied (this represents a sample ≥ 33% of first grade

classrooms in each school studied). To be able to keep the schools anonymous as

requirement by the Department of Education of Puerto Rico, the schools were classified

as 001,002, 003 and 004.

3.05.1. Data Recollection Procedure Phase One

This research was conducted in two phases. The first phase of the study was

conducted in the month of February 2008. Each school was monitored for two days, one

day for each air sample (one day for indoor sample and one day for outdoor sample),

due to instrumentation availability. According with environmental engineers Nelson

Moreno and Israel Matos from the Environmental Quality Board (EQB) of Puerto Rico

and Francisco Claudio form the Environmental Protection Agency (EPA) of Puerto Rico,

if the research does not contemplate comparing the impact of a known emission source

in the school, it is not necessary to take indoor and outdoor samples at the same time

(personal communication March 24, 2008). Since the base of this research was to study

the environmental conditions inside and outside the classroom and not the impact of a

known emission source we can obtain the TVOC data from indoor and outdoor samples

in different days.

Indoor air samples were positioned at the back of the classroom as per stated by

the Department of Education of Puerto Rico to minimize student distraction. If the

school had more than one first grade classroom, the Director of each school had the

authority by the Department of Education of Puerto Rico to choose in which classroom

the measurements would take place. All of the outdoor air samples were taken near the

39

front of the schools in favor of wind direction. The position placement of the instrument

at the back of the classroom and in the outside was indicated by the Director of each

school as required by the Department of Education of Puerto Rico. Because of this

reason, the instrument height position varied from approximately 0.3 to 2 m. The TVOC

were measured for a period of approximately eight (8) hours monitoring to cover school

hours. For the duration of air measurements, indoor and outdoor temperature and

relative humidity were obtained. Wind velocity range was obtained at the initial and

finalization of TVOC measurements in each school at each sample collection. Also, the

quantity of total students and personnel and the quantity of total students and personnel

with respiratory conditions of the total of first grade level in each school was obtained

directly from each Director of the school studied. This data was collected to know how

many children and adults can have possible respiratory health problems in schools if

TVOC levels exceed the literature guidelines.

In any air pollution prediction procedure, local topography and meteorological

events, such as temperature, pressures, and wind velocity, play significant roles (Lee et

al. 2006). The air pollutant concentrations and meteorological variable measurements

provide basic data for air pollution modeling and prediction period. To be able to quantify

the interpretation of air quality observations, it is required to obtained information of the

atmospheric characteristics for the study site. With this purpose the general data for the

meteorological conditions throughout the month of February 2008 were obtained from

the Meteorological Assimilation Data Ingest System (MADIS) Caguas Station. MADIS is

dedicated toward making value-added data available from the National Oceanic and

Atmospheric Administration's (NOAA) Earth System Research Laboratory (ESRL) Global

Systems Division (GSD) (formerly the Forecast Systems Laboratory (FSL)). The

purpose of MADIS is to improve weather forecasting by providing support for data

40

assimilation, numerical weather prediction, and other hydro meteorological applications

(NOAA 2007a, NOAA 2007b, LeMone 2006).

3.05.2. Data collection procedure Phase Two

The second phase of this research was conducted in September of the same

year, 2008. This phase was performed taking in consideration the TVOC data obtained

in phase one. Because of the previous results in the second phase of this research, only

one school of all the schools studied in phase one was chosen. This 004 school based

on the data recollected in phase one seemed to have this distinctive trait. For that fact,

the school 004 was monitored for eight days, altering TVOC measurements for indoor

and outdoor air samples; this is, one day for indoor sample then one day for outdoor

sample, due to instrumentation availability.

As in phase one, the Director of the school had the authority by the Department

of Education of Puerto Rico to choose in which first grade classroom the measurements

would take place. The position placement of the instrument at the back of the classroom

and in the outside was indicated by the Director of the school as required by the

Department of Education of Puerto Rico. Because of this reason, the instrument height

position varied from approximately 0.3 to 2 m. All of the outdoor air samples were taken

near the front of the schools in favor of wind direction. The TVOC were measured for a

period of approximately eight (8) hours monitoring to cover school hours for a total of

eight (8) air samples (four (4) indoor air samples and four (4) outdoor air samples).

According with environmental engineers Nelson Moreno and Israel Matos from the

Environmental Quality Board (EQB) of Puerto Rico and Francisco Claudio form the

Environmental Protection Agency (EPA) of Puerto Rico, if the research does not

contemplate comparing the impact of a known emission source in the school, it is not

necessary to take indoor and outdoor samples at the same time (personal

communication March 24, 2008).

41

For the duration of air measurements, indoor and outdoor temperature, relative

humidity and pressure were obtained. Also, the quantity of total students and personnel

and the quantity of total students and personnel with respiratory conditions of the total of

first grade level in the school was obtained directly from the Director of the school

studied. This data was collected once again to know how many children and adults can

have possible respiratory health problems in school if TVOC levels exceed the literature

guidelines, since the environmental agencies that regulate indoor and outdoor air quality

in Puerto Rico do not have a TVOC guidelines.

Section 3.06. Data analysis

A descriptive statistical analysis was prepared using the statistical analysis

program Minitab®. The average of each school, the standard deviations, and

maximums and minimal TVOC levels were obtained and determined. To be able to

grasp a global analysis of all the schools, a descriptive statistical analysis was

performed; a normality test and a variance test were completed to obtain the p-value

which is a probability, with a value ranging from zero to one. Since these statistical

analysis tests were not normal (p-value<0.05) giving a p-value = 0.010 and did not have

homogeneity (p-value<0.05) giving a p-value = 0.000, non parametric tests were

prepared. Non parametric tests in its majority are based in data organization and do not

require population normality. A Mann-Whitney statistical test was done given that of

independent samples, which is used when two independent samples of populations want

to be compared; it is an alternative test to the t test. The hypotheses used for this test

were: Null Hypothesis (H0): medianIndoor = medianOutdoor; Null Hypothesis (H0): Indoor

(medianRural = medianUrban); Null Hypothesis (H0): Outdoor (medianRural = medianUrban).

Also a statistical Kruskal-Wallis test was used to compare more than two groups; this is

an alternative test to the F test. The hypotheses used for this test were: Null Hypothesis

(H0): Indoor (medianSchool001 = medianSchool002 = medianSchool003 = medianSchool004);

42

Alternative Hypothesis (H1): at least one school differs; Null Hypothesis (H0): Outdoor

(medianSchool001 = medianSchool002 = medianSchool003 = medianSchool004); Alternative

Hypothesis (H1): at least one school differs.

43

Chapter Four

Results

Section 4.01. Phase One of the Research

The schools of the Municipality of Caguas Puerto Rico are divided in two

Districts: Caguas I and Caguas II. Random analysis was prepared using the statistical

analysis program Minitab® to select the district of study resulting in Caguas II and a

representative sample of urban and rural schools were studied. There were a total of

four schools studied, two rural and two urban. These rural and urban schools

constituted a 33% and 40% respectively of the total schools of this District. The school

classification is given by the Department of Education of Puerto Rico, and as petitioned,

the names of the schools were kept anonymous.

As a brief description (see Appendix 13) school 001 is a rural school next to a

church and a baseball park. The school is situated in front of the main road. School 002

is an urban school next to a recreational - sports park and an emergency vehicle center.

This school is also undergoing construction of new facilities. This construction occurs

during school hours form approximately seven in the morning (7:00 am) to four in the

afternoon (4:00 pm). School 003 is also an urban school, situated in the city next to

main roads. Adjacent to this school is a funeral parlor and an automotive repair college.

School 004 is a rural school with roughly little vegetation around. It is located near a

highway in front of a main road and next to it is a food and animal center and a uniform

fabric industry.

Random analysis was prepared using the statistical analysis program Minitab® to

randomly select the school grade resulting in first grade and in order to standardize

research variables, all the samples were taken in the first floor of each school. The

43

44

quantity of students and personnel acquired in each school was given by each school

Director (see Table 4.01).

Table 4.01. Total of first grade students and first grade personnel in each school

studied.

School

Total of fist grade students Total of first grade personnel

001 42 4

002 85 13

003 38 4

004 30 2

Because VOC’s can cause respiratory irritation we obtained the percentage total

of all the students and personnel of the first grade that had respiratory conditions in the

schools (see Table 4.02). This data was given by the Director of each school studied.

Of all the schools studied school 004 had the highest percent of first grade students and

personnel with respiratory conditions.

45

Table 4.02. Percentage of first grade students and personnel with respiratory conditions.

School

% Total of first grade students and first grade personnel

with respiratory conditions

001 15.2

002

13.3

003

15.8

004

34.4

To be able to compare indoor and outdoor TVOC levels, we obtained the

meteorological data for Caguas, Puerto Rico from the Meteorological Assimilation Data

Ingest System (MADIS) Caguas Station. MADIS data indicate that outdoor

meteorological conditions in this municipality do not fluctuate much; daily or weekly

during the month of February 2008 (see Appendices 14 and 15). We can note that the

general meteorological conditions during the days of air quality measurements in the

schools studied are approximately the same. This information suggests that the

meteorological conditions at the schools and in the classrooms during the sample days

should not affect the TVOC levels because meteorological conditions do not vary

markedly daily or weekly. Because of this finding, indoor and outdoor levels of TVOC

can be compared even if there is no known VOC source.

During the sampling, the temperature and relative humidity were obtained and as

presented below (see Tables 4.03 and 4.04), we can observe that both the temperature

and relative humidity are higher outdoors than indoors.

46

Table 4.03. Temperature data obtained for each school for indoor and outdoor samples.

School Type of

School

Indoor Temperature (°C)

Outdoor Temperature (°C)

Mean*

(± SD)

Max

Min

Mean*

(± SD)

Max

Min

001 Rural 25 ± 1 27.1 22.8 26 ± 2 28.9 21.7

002 Urban 22.8 ± 0.8 25.9 22.4 27 ± 1 28.9 24.0

003 Urban 27 ± 1 28.9 24.9 32 ± 4 41.2 22.4

004 Rural 27 ± 2 30.1 23.6 30 ± 3 40.3 27.3

*n = 29

Table 4.04. Percentage of relative humidity data obtained for each school for indoor and

outdoor samples.

School Type of

School

Indoor Relative Humidity

(%)

Outdoor Relative Humidity

(%)

Mean*

(± SD)

Max

Min

Mean*

(± SD)

Max

Min

001 Rural 75 ± 5 85.3 66.1 64 ± 10 80.8 49.2

002 Urban 61 ± 3 67.9 56.9 63 ± 8 78.7 52.7

003 Urban 62 ± 8 81.1 51.8 51 ± 12 81.1 31.2

004 Rural 61 ± 12 82.3 42.9 47 ± 7 56.6 29.3

*n = 29

47

As for indoor ventilation in the schools (see Table 4.05), schools 001 and 003

have cross or natural window ventilation and schools 002 and 004 have artificial

ventilation (air conditioning system). Ironically, one of each urban and rural schools

studied had one school with natural window ventilation and one school with artificial

ventilation. The Director of each school had the authority (by the Department of

Education of Puerto Rico) of choosing which first grade classroom the investigation

would take place (if there was more than one first grade classroom), which meant that

there was no control over the indoor ventilation variable in this study. We can also

observe that wind velocity range is higher outdoor than indoors for all four schools.

Table 4.05. Wind velocity obtained for each school for indoor and outdoor samples.

School Type of

School Type of Ventilation

Indoor (m/s) Outdoor (m/s)

Max Min Max Min

001 Rural Natural Ventilation 0.0 0.0 2.6 0.0

002 Urban Artificial Ventilation/

Natural Ventilation 0.0 0.0 2.0 0.0

003 Urban Natural Ventilation 0.0 0.0 0.8 0.4

004 Rural Artificial Ventilation/

Natural Ventilation 0.5 0.0 1.1 0.3

*With a margin of error = ± 3%.

TVOC measurements are shown in Table 4.06. It can be seen that not all the

schools had detectable TVOC measurements and that TVOC maximum concentration

48

vary from school to school and indoor versus outdoor, which indicates that each school

is unique. When comparing types of indoor ventilation in the classrooms studied in each

school with indoor TVOC measurements (see Table 4.07), it can be observed that higher

peaks were found in classrooms that had artificial ventilation versus the classrooms that

had cross or natural ventilation.

Table 4.06. Summarized indoor and outdoor TVOC results measurements for the

schools studied.

School Type of School

Indoor TVOC (mg/m3) Outdoor TVOC (mg/m3)

Mean*

(±SD)

Max Min Mean*

(±SD)

Max Min

001 Rural 0 ± 0 0.0 0.0 0 ± 0 0.0 0.0

002 Urban 0.0 ± 0.6 47.20 0.0 0 ± 5 76.50 0.0

003 Urban 0.0 ± 0.3 22.07 0.0 0 ± 2 126.88 0.0

004 Rural 18 ± 31 468.91 0.0 5 ± 16 95.16 0.0

*n=5560

49

Table 4.07. Comparison of types of indoor ventilation and TVOC results measurements

for the schools studied.

Type of Ventilation School

Indoor TVOC (mg/m3)

Mean*

(±SD)

Max

Cross or Natural Ventilation 001 0 ± 0 0.0

003 0.0 ± 0.3 22.07

Artificial Ventilation /

Natural Ventilation

002 0.0 ± 0.6 47.20

004 18 ± 31 468.91

*n=5560

When graphing all the TVOC data measurements obtained at each school

individually, which were take every five (5) seconds, we found that no TVOC detection

levels were observed for rural school 001 at indoor and outdoor measurements. For

urban school 002, TVOC indoor measurements were also below the detection limit

except for one measurement early in the morning at 7:44 am before classes started with

a concentration of 47.20 mg/m3. For this school outdoor measurements were different.

Early in the morning from 8:10-8:25 am high measurements were observed with the

highest peak at a concentration of 76.50 mg/m3. In the afternoon it can be observe

some random TVOC measurements at around 13:00 - 14:20 pm. TVOC measurements

obtained for this urban school showed differences in the outdoor and indoor sample

measurements for this school (see Figure 4.01).

50

Figure 4.01. Concentration of TVOC versus time for school 002 for indoor and outdoor

TVOC data (n=5560).

For the majority of indoor and outdoor measurements for urban school 003 were

also below the detection limit except for some measurements late in the afternoon. For

the indoor sample there was a measurement at 15:34 pm after classes had concluded

that corresponds to a concentration of 22.07 mg/m3. For the outdoors measurements for

the same school, there were various measurements also in the late afternoon starting at

around 15:28 pm – 15:35 pm after classes had ended with the highest peak at a

concentration of 126.88 mg/m3. This is the highest TVOC concentration measurement

51

for an outdoor sample of all the schools studied. Figure 4.02 shows the chart of TVOC

measurements obtained for school 003 and the differences in the outdoor and indoor

sample measurements can be observed predominantly in the late afternoon for this

school.

Figure 4.02. Concentration of TVOC versus time for school 003 for indoor and outdoor

TVOC data (n=5560).

Of all the schools studied, rural school 004 showed the highest TVOC

concentration for indoor measurements with a peak of 468.71 mg/m3 at around 7:43 am.

For this school, a variety of measurements can be observed in the morning both for

indoor and outdoor samples. The highest concentration measured for the outdoor

sample of this school was 95.16 mg/m3 at around 8:00 am. Also in the late afternoon

there was a TVOC measurement of 9.65 mg/m3 at around 15:24 pm. Figure 4.03 shows

52

the chart of TVOC measurements obtained for school 004 and we can observe the

differences in the outdoor and indoor sample measurements predominantly in the

morning.

Figure 4.03. Concentration of TVOC versus time for school 004 for indoor and outdoor

TVOC data (n=5560).

Statistical analyses were done in the statistical computer program MiniTab®.

The statistical tests done were nonparametric because the data obtained for the

concentration of TVOC indoors and outdoors were not normal (“p-value” = 0.010) and

did not had variance homogeneity (“p-value” = 0.000). The Mann-Whitney test was done

to compare two populations using independent samples (“p-value” = 0.000). This is an

alternative test to the t test to be able to compare two averages using independent

samples. The hypotheses used for this test were: Null Hypothesis (H0): medianIndoor =

53

medianOutdoor; Null Hypothesis (H0): Indoor (medianRural = medianUrban); Null Hypothesis

(H0): Outdoor (medianRural = medianUrban). Also a statistical Kruskal-Wallis test was used

to compare more than two groups; this is an alternative test to the F test. The

hypotheses used for this test were: Null Hypothesis (H0): Indoor (medianSchool001 =

medianSchool002 = medianSchool003 = medianSchool004); Alternative Hypothesis (H1): at least

one school differs; Null Hypothesis (H0): Outdoor (medianSchool001 = medianSchool002 =

medianSchool003 = medianSchool004); Alternative Hypothesis (H1): at least one school differs.

Section 4.02. Phase Two of the Research

This phase was performed taking in consideration the TVOC data obtained in

phase one. TVOC levels obtained in phase one indicated that TVOC concentration

levels seem not to be an ongoing problem in all the elementary public schools studied in

Caguas District II although some levels are higher than the scientific guidelines for

TVOC in the air, due to the fact that most of the time there were no detectable levels of

TVOC that could cause any potential health problems in children or in school personnel

(>25 mg/m3). However, of all the schools studied school 004 in phase one was chosen

for a more extensive study because this school seemed to have this distinctive trait

compared to all the other schools studied having the highest TVOC concentration for

indoor and outdoor measurements. For that fact, the school 004 was monitored for total

of eight days altering TVOC measurements for indoor and outdoor air samples; this is,

one day for indoor sample then one day for outdoor sample, due to instrumentation

availability.

As a reminder, school 004 is a rural school with roughly little vegetation around.

It is located near a highway in front of a main road and next to it is a food and animal

center and a uniform fabric industry. Because VOC can cause respiratory irritation we

obtained the percentage total of all the students and personnel of first grade that had

54

respiratory conditions in the schools (see Table 4.08). The quantity of students and

personnel was obtained directly from the Director of the school to be able to know how

many of the first grade students and personnel suffered from respiratory conditions.

Table 4.08. Total of first grade students and first grade personnel and the total

percentage with respiratory conditions in the 004 school studied.

School

Total of fist

grade students

Total of first

grade personnel

% Total of first grade students and first

grade personnel with respiratory

conditions

004 25 1 19.23

This school had only one first grade classroom which uses artificial as well as

natural ventilation. The ventilation mechanism used in the classroom is at the discretion

of the school teacher. The first grade teacher indicated that she used the artificial

ventilation in the morning and natural ventilation in the afternoon during the eight (8)

days research study.

The position placement of the instrument at the back of the classroom and in the

outside was indicated by the Director of the school as required by the Department of

Education of Puerto Rico. Because of this reason, the instruments height position varied

from approximately 0.3 to 2 m. All air measurements (TVOC, relative humidity and

temperature) were measured for a period of approximately 8 hours monitoring to cover

school hours. All of the outdoor air samples were taken near the front of the schools in

favor of wind direction.

55

During the acquirement of TVOC measurements temperature and relative

humidity data was obtained every half hour in the school. It can be observed from Table

4.09 and Table 4.10 that the temperature and relative humidity did not vary much

comparing indoors and outdoors.

Table 4.09. Temperature data obtained for the school 004 for indoor and outdoor

samples.

Day

Indoor Temperature (°C) Outdoor Temperature (°C)

Mean*

(± SD)

Max

Min

(°C)

Mean*

(± SD)

Max

Min

1 32 ± 1 34.1 29.3

2 29 ± 2 32.4 27.1

3 31 ± 4 35.3 30.1

4 29 ± 2 31.4 25.8

5 29 ± 2 31.7 25.9

6 33 ± 4 38.8 24.1

7 30 ± 2 32.7 25.4

8 34 ± 3 38.6 26.9

*n = 17

56

Table 4.10. Percentage of relative humidity data obtained for the school 004 for indoor

and outdoor samples.

Day

Indoor Relative Humidity (%) Outdoor Relative Humidity (%)

Mean*

(± SD)

Max

Min

(°C)

Mean*

(± SD)

Max

Min

1 55 ± 6 67.9 47.2

2 49 ± 2 51.7 43.8

3 65 ± 4 69.2 54.7

4 71 ± 9 86.6 57.8

5 70 ± 8 85.0 57.1

6 54 ± 15 81.5 44.1

7 65 ± 6 78.8 57.7

8 60 ± 2 91.7 49.4

*n = 17

The data obtained for eight days monitoring at this rural school showed basically

the same pattern of detectable levels of TVOC indoors and outdoors samples as in

phase one of this research (see Figures 4.04 and 4.05). For this school, a variety of

measurements can be observed in the morning both for indoor and outdoor samples.

Rural school 004 showed high TVOC air concentration for indoor measurements with a

maximum peaks that fluctuate in the high four hundreds mg/m3 in the morning.

Outdoors, this school showed TVOC air concentrations measurements with maximum

peaks that fluctuate in the high hundreds mg/m3 in the morning (see Table 4.11). When

57

calculating the averages and maximum peaks of the TVOC measurements obtained

from indoor and outdoor air samples it can be observed that both averages and

maximum peak measurements are higher indoors than outdoors (see Table 4.11) as

observed in phase one of this research.

Figure 4.04. Concentration of TVOC versus time for indoor air measurements of school

004 (n=5563).

58

Figure 4.05. Concentration of TVOC versus time for outdoor air measurements of

school 004 (n=5563).

59

Table 4.11. Summarized indoor and outdoor TVOC results measurements for the school

004.

Day

Indoor TVOC (mg/m3) Outdoor TVOC (mg/m3)

Mean*

(±SD)

Max Min Mean*

(±SD)

Max Min

1 18 ± 27 409.04 0.0

2 10 ± 20 183.13 0.0

3 13 ± 26 496.13 0.0

4 10 ± 20 191.56 0.0

5 16 ± 25 475.39 0.0

6 11 ± 21 152.28 0.0

7 16 ± 24 452.38 0.0

8 8 ± 20 179.00 0.0

*n=5563

In this chapter, the TVOC air measurements and the climatological and

meteorological data obtained in the schools studied have been presented. In the next

chapter, the results and findings are discussed. Also in the next chapters are mentioned

the conclusions of this research and recommendations for future air quality

investigations are offered.

60

Chapter Five

Discussion, Conclusions and Recommendations

Section 5.01. Introduction of Discussion

The purpose of this study was to investigate the TVOC concentration levels

indoors and outdoors in elementary public schools of Caguas II District in Puerto Rico

since these studies have never been done before. This environmental air quality

perspective is growing in importance to school systems around the nation, especially as

it is related to the health protection and educational performance of students and

teachers (Berry 2008). It is becoming increasingly recognized that the indoor

environments of schools are directly related to human health, image, self-esteem, and

attitude, all of which affect academic performance (Berry 2008). The idea of this

exploratory research was to serve as a base study for future investigations for the

determination of TVOC levels in the air, in view of the fact that air quality in schools can

have a substantial impact on children’s health.

This study was divided in two phases. Phase one of this research was done in

February of 2008. A representative randomly selected sample of rural and urban

elementary schools of Caguas II District of the Municipality of Caguas Puerto Rico were

studied. TVOC Samples of indoor and outdoor air were taken in a first grade classroom

selected by the Director of each school studied for a period of one day each sample (one

day indoors and one day outdoors). The second phase of this research was done in

September of 2008. Based on the TVOC results of each school from phase one, only

one school was studied for eight (8) days taking in alternation indoor and outdoor TVOC

measurements samples. As part of the limitation in the study, there were delays in

obtaining the information necessary to know the number of student and personnel with

respiratory conditions given by each Director of each school studied. Also, it was difficult

60

61

to obtain information if the students that were absent in the day of sampling was due to

respiratory sickness.

Section 5.02. Discussion of Phase One of the Research

Taking in consideration the surroundings around at the schools studied in

Caguas II District we can observe various air quality situations that can affect the air

quality in the school. Some of these situations are that the schools are located near

main roads, some have construction work going on during schools hours, some have

mold growing on the latches of the roof, and others are next to possible emission

sources such as sewers and auto repair colleges (see Appendix 16). These situations

are common air quality problems that are representative of both urban and rural

elementary public schools of Caguas II District. These sources can emit volatile organic

compound at high concentrations that could exacerbate respiratory conditions among

students and/or faculty members, as stated in the literature review.

When statistically comparing the total of indoor and outdoor TVOC

concentrations of all the schools studied using the Mann-Whitney statistical test, strong

evidence can be found that outdoor concentrations of TVOC are higher than indoors

because the p-value obtained was 0.00 which is less than 0.05. This also can be

observed in the mean TVOC concentrations and its standard deviations obtained in this

research (see Table 4.06). This finding is contrary to air quality investigations found in

the scientific literature were indoor samples are higher than outdoor samples due to

building construction materials (Minnesota Department of Health 2005, Sweet et al.

1992). This finding indicates that for elementary public schools in Caguas II District

indoor TVOC levels will depend on the activities arranged in the classroom or from a

near outdoor source if ventilation is inadequate. Contrary to indoor TVOC levels found

in the schools studied, outdoor TVOC levels will depend on the surroundings near the

school. Due to financial constraints, indoor and outdoor samples could not be obtained

62

the same day which could be considered as a limitation of this study. As for TVOC

determination, there was a characterization limitation in determinating and identifying

which types of VOC constituted the TVOC parameter. Even though limitations were

inevitable, the results obtained in this research are reliable to be able to establish

conclusions in respect to the objective and hypothesis of this research.

When statistically comparing rural and urban schools TVOC concentrations using

the Mann-Whitney statistical test a p-value of 0.00 was obtained which is less than 0.05

indicating that urban schools are more exposed to TVOC air quality problems than rural

schools. This is true for both indoor and outdoor measurement comparison for rural

schools versus urban schools, because all urban schools studied had detectable levels

of TVOC and not all rural schools studied had detectable TVOC levels. However,

consideration should be made when relating exposure with health effects due to type of

VOC characterization and concentration of each VOC that constitutes the TVOC

measurement obtained. With many pollution sources found in urban areas, it may be

difficult to single out which sources could be the possible source causing the problem. A

possible common source could be traffic proximity near the school. Because several

reactive hydrocarbons are formed during combustion and can accumulate in the

atmosphere (Leikauf 2000, Paliulis 2007). The Kruskal-Wallis statistical test for TVOC

indoor and outdoor concentration in schools results were “p-values” of 0.000 which

indicate that at least one school differs for indoor and outdoor sample comparison which

makes every schools studied unique.

The research data obtained for the schools studied indicate that the students are

exposed to air quality problems. As stated by Godwin et al. (2006), IAQ problems may

be exacerbated in schools due to inappropriate landscaping with minimal or poor

drainage, basic and minimal engineered ventilation and if any air conditioning system,

the lack of preventative maintenance, and crowded conditions.

63

Since there are no TVOC environmental agency guidelines for indoor and

outdoor in the US and in PR, a number of international scientific guidelines can be used

to provide some indication as to whether levels measured in the schools are above

desirable limits (Ajiboye et al. 2006, Raw et al. 2004). The indoor air goal

concentrations recommended in 1992 by the National Health and Medical Council

(NHMC) in Australia, is 500ug/m3 (0.5 mg/m3) for TVOC by one hour averaging period

(Brown 1997). A TVOC concentration > 500ug/m3 indicates significant present of

sources. Significant discomfort and headaches are likely if concentrations fall in the

range of 3mg/m3-25mg/m3 (Grimsrud 2004, AERIAS 2007). As for TVOC monitoring by

photoionization detection (PID) (calibrated with isobutylene), the recommended

guidelines are (RAE Systems Application Note AP-212, 2008):

<0.30 mg/m3 normal outdoor air

0.30-0.2 mg/m3 for normal indoor air

>1.15 mg/m3 indicates potential air quality contamination

Comparing TVOC mean concentrations obtained in the schools studied (see

Appendices 14 and 15) with these guidelines, it can be observed that the TVOC average

levels found in schools are between the TVOC limits found in the scientific literature with

the exception of school 004. The TVOC measurements obtained for this school in

particular may indicate potential air quality contamination. But even though the TVOC

mean concentrations levels found in the other schools studied, students and personnel

are still exposed to VOC concentrations because in the scientific literature TVOC

concentrations typically range from 50-1000 µg/m3 over long periods of time but TVOC

levels can reach hundreds of mg/m3 for periods of minutes and hours (European

Collaborative Action 1997, Daisey et al. 2003). A tendency of TVOC measurements

exceeding the scientific literature guidelines can be observed in Figure 5.01 and 5.02.

This VOC exposure could be harmful to human health depending on the type and

64

concentration of the VOC found in the air that constitutes the TVOC parameter detected

at each school. The exposure to TVOC can contribute to exacerbation of respiratory

conditions depending on the type of VOC’s that constitute the Total VOC. Also,

exacerbation of respiratory conditions can occur when the TVOC peaks exceed the

concentration guidelines for a period of time in the air and are inhaled.

Based on the guidelines mentioned above, when comparing indoor and outdoor

maximum TVOC peaks and means concentration measurements in each school studied,

it can be observed that the TVOC measurements tend to be higher outdoors compared

to indoor mean levels and peak value (see Figures 5.01 and 5.02; Appendix 17). These

findings are contradictory to those found in the literature were indoor TVOC

measurements exceed those found outdoors. Although, exception can be found in

school 004 data which demonstrates that there is either an indoor source or there is poor

ventilation exchange with the outdoors. These TVOC measurements in school 004 can

be due to classroom cleaning before classes start and poor ventilation exchange once

the air conditioning unit was turned on. Interestingly this school is the school which has

the highest percentage of respiratory conditions among students and personnel. It is

also the school with the highest TVOC measurement peak among the schools studied

which makes this school the most vulnerable of all the schools studied in terms of TVOC

exposure. As part of the limitations of this research wind direction could not be obtained

which is a constraint if source is wanted to be known.

65

Figure 5.01. Indoor TVOC mean concentrations and maximum peak observed at the

schools studied.

66

-20

0

20

40

60

80

100

120

140

001 002 003 004

Schools

Concentration (mg/m3)

Mean (n = 5560)

Max Peak

Figure 5.02. Outdoor TVOC mean concentration and maximum peak observed in the

schools studied.

Comparing indoor samples with the outdoor sample measurements, in Figures

5.03 and 5.04 we can notice that there is a source or an activity occurring either at the

school or near the school that produces VOC contamination. This can be seen in school

004 where there is a prominent source that is emitting emissions near the school, as

detected in the early morning hours. The TVOC outdoor sources could be a near by

textile industry (54 m distance), a pet shop and animal food center (20 m distance), a

closed propane gas storage facility (1.04 km distance) or even a gasoline station near

by. Indoor TVOC sources could come from outdoor sources when poor ventilation is in

place or from early classroom cleaning practices. Also school 002 has a source near the

school that causes sporadic VOC emissions as seen in the outdoor sample. This VOC

67

source could be the sewers in front of the school that when wind direction and velocity

change, TVOC can be detected. Another source could be a plastic basin close to the

classroom which is used in early morning cleaning process. More comprehensive

studies should be conducted to characterize the volatile organic compounds found in

these schools to further determine the source and potential health effects to the students

and school personnel.

Figure 5.03. Comparison chart for indoor and outdoor TVOC maximum peak

measurements for each school studied.

68

Figure 5.04. Comparison chart for indoor and outdoor TVOC averages for each school

studied (n Indoor and Outdoor = 5560).

Section 5.03. Discussion of Phase Two of the Research

This research was conducted in September of 2008. This phase was performed

taking in consideration the TVOC data obtained in phase one. TVOC levels obtained in

phase one indicated that TVOC concentration levels seem not to be an ongoing

problems in the elementary public schools studied due to the fact that most of the time

there were no consecutive detectable levels of TVOC that could cause any potential

health problems in children or in school personnel (>25 mg/m3). However, there were

still detectable levels in which depending on the source of emission near or at the school

could cause health concerns in the long run if this was a constant emitting source. This

school, school 004, based on the data recollected in phase one seemed to have this

distinctive trait. For that fact, the school was monitored for a total of eight (8) days

69

altering TVOC measurements for indoor and outdoor air samples; this is, one day for

indoor sample then one day for outdoor sample, due to instrumentation availability.

Results indicate that there was not a considerable change observed of the TVOC

air levels detected indoors and outdoors in the school compared to those obtained in

phase one in the month of February, even though there is a seven month difference in

the detection of TVOC air levels. In the figures 5.05 and 5.06, a comparison of indoor

and outdoor maximum TVOC peaks and means concentrations can be observed. The

TVOC air measurements are higher indoors (13mg/m3-18mg/m3) than outdoors

(8mg/m3-11mg/m3). These findings are consistent to those found in the literature were

indoor VOC’s are found in levels in order of magnitude higher than those outdoors.

These results indicate that there is in fact a source next or close to the school that can

become a health concern to students and personnel if and when the TVOC levels

exceed those from the literature guideline (3mg/m3 – 25mg/m3). A more detailed

characteristic study needs to be done in this school in particularly to be able to identify

the source.

70

Figure 5.05. Outdoor TVOC mean concentration and maximum peak observed in the

school 004 for the days studied.

71

Figure 5.06. Indoor TVOC mean concentration and maximum peak observed in the

school 004 for the days studied.

Higher peaks of TVOC indoor air measurements can be attributed to early

cleaning practices in the classroom and poor air exchange ventilation since in the

morning the air conditioning was turned on as soon as class started. However, this

statement should be confirmed with a more detailed characterization research due to the

fact that outdoor TVOC air levels are also observed in the morning but in less

concentration. This can be observed comparing indoor samples with the outdoor

72

sample average measurements and maximum concentration measurements (see

Figures 5.07 and 5.08).

Figure 5.07. Comparison chart for indoor and outdoor TVOC averages for school 004

(n Indoor and Outdoor = 5563).

73

Figure 5.08. Comparison chart for indoor and outdoor TVOC maximum measurements

for school 004 (n Indoor and Outdoor = 5563).

Section 5.04. Conclusion

The objective of this study was to investigate the total volatile organic

compounds (TVOC) levels upon indoor and outdoor air quality in a representative

sample of elementary public schools of the Caguas II District Municipality of Caguas,

Puerto Rico. Since TVOC levels detected in scientific literature research are attributed

to building material construction such as wood and gypsum board, we would expect no

TVOC levels to exceed in building schools in Puerto Rico because they are made of

concrete. However, baseline measurements of this research compared to TVOC

74

guidelines from the scientific literature show that total volatile organic compounds do not

seem to be an on-going problem in elementary public schools of Caguas II District

because for most of the time of sampling measurements, there were no detectable

levels of TVOC that could cause any potential health problems in children or in school

personnel (>25 mg/m3). Nevertheless, there were still detectable levels in which

depending on the source of emission near or at the school and its emission or off

gassing of TVOC could cause health concerns in the long run if this was a constant

emitting source or if a student or school personnel has an existing respiratory problem.

These TVOC air measurements were compared to those from the scientific literature

guidelines because there are no TVOC indoor or/and outdoor guidelines from

environmental agencies in the United States nor in Puerto Rico.

For rural school 004 of this research seem to have this distinctive trait since there

was a continuous TVOC air detection during every air sample taken at this school.

Every outdoor and indoor TVOC air measurement sample seems to have the same

pattern of high TVOC peaks early in the morning decaying close to midday. Indoor

emission source could come from cleaning products due to early cleaning practices in

the classroom and outdoor emission sources could come from nearby industries or

transportation emissions. As it can be seen, the characteristics of VOC concentrations

in ambient air depend on the strength of each emission source close to the schools

studied. However, continuous measurements should be made integrated with a risk

assessment study, to determine any health related effects, so this conclusion may be

premature.

A more detailed environmental research with the characterization of VOC in air

would provide first hand information needed to define a correlation between respiratory

diseases and air quality in schools. The study’s limited explanatory power suggest that

variables omitted from the study due to data constrains (e.g. characterization

75

measurements because of lack of instrumentation) are likely to be better predictors of

severe incidents of respiratory diseases among students.

Section 5.03. Recommendations

An organized management plan or cleaning program will contribute to a significant

improvement. This should include:

1. Facility planning – establishing procedures and guidelines for building

maintenance, appropriate scheduling of these activities and use of low

emitting cleaning products. Cleaning is the most fundamental management

strategy. Classroom cleaning should be arranged late in the afternoon after

classes have ended, so VOC cleaning products emissions could dissipate

overnight

2. Baseline monitoring – two (2) times a year; example prior to opening school

each semester.

3. Good communication plan between school personnel.

As identified in this research a more detailed identification of VOC study should

be conducted especially in school 004, to be able to characterize if the concentrations of

VOCs detected can cause health problems. The availability of such data will allow the

research community to better quantify the human health risk associated with some of the

most dangerous indoor environmental contaminants. Protection of human health

against disease and injury caused by toxic chemicals in the environment is the ultimate

goal of risk assessment and management. The protection of children against toxic

chemicals in the environment will require fundamental and far-reaching revisions of

current approaches to surveillance, toxicity testing, and risk assessment.

From a public health’s stand point, because low levels of ambient air pollution

appear to have exerted a modest impact in terms of prediction, this finding underscore

the importance of delineating the VOC contribution of air quality. Future investigations

76

will be valued not merely as academic but as means for resolving and improving air

quality. Given that the General Accounting Office of the United States concluded that

one in five schools has IAQ problems, and given that thousands of schools are slated for

construction or renovation within the next five (5) years, the need to identify simple,

effective, energy-efficient ways of resolving these IAQ problems is both obvious and

significant (Bayer et al. 2007).

For VOC monitoring, as should be any air quality data, the instrumentation or

method response should be timely, continuous, should have high sensitivity and

accuracy, and the instrument should be field operable or should be accompanied or

coupled by different methods or instrumentation that are field operable for

complementation. The best strategy for improving air quality is through the identification

and control of pollutants at their source. The ideal circumstances would be the

identification of the contaminants, and so, an environmentally friendly solution.

77

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Appendices

90

91

Appendix One

Caguas, Puerto Rico

Figure A1. Map location of the Municipality of Caguas in Puerto Rico.

Source: Puerto Rico Planning Board 2007.

92

Appendix Two

Secondary production of urban smog oxidants by photochemical reactions in the

atmosphere

Atmospheric oxidant production:

1. NO + VOC → NO2 (nitrogen oxide)

2. NO2 + UV→NO + O (nitric dioxide + atomic oxygen)

3. O + O2 → O3 (ozone)

4. NO + VOC → PAN, etc. (peroxyacetyl nitrate)

Net results:

NO + VOC + O2 + UV→ O3, PAN and other oxidants

Source: Cunningham et al. 2003.

93

Appendix Three

Asthma prevalence in the year 2000

Figure A3. Map of weighted prevalence of asthma in the continental USA and its

territories during 2000.

Source: Perez-Perdomo et al. 2003.

94

Appendix Four

Volatile organic compound sources

Table A4. Typical sources of air pollutants

Outside Sources

Polluted Outdoor Air: Pollen, dust, fungal, industrial and vehicle

emissions.

Nearby Sources: loading vehicle parking or loading, odours

from dumpsters, unsanitary debris or building exhaust

near outdoor air intakes.

Underground sources: soil gases, pesticides, leakage from

underground storage.

Building Equipment: Emission from office equipment, cleaning

processes, atria planters and other wet areas.

Component/

Furnishings

Components: microorganisms growing on soiled or water-

damaged materials, materials containing volatile

organic compounds, inorganic compounds, or damaged

asbestos, materials that produce particles or fibers.

Other

Indoor

Sources

Copy/print areas, food preparation/eating areas, cleaning

materials, emission form trash, pesticides, odours and

volatile organic compounds from paint, sealants or

adhesives; markable felt pens, pests, renovation

activities.

Source: Ministry of National Health and Wealfare 1995.

95

Appendix Five

Volatile organic compounds emission by source sector in 2002

The chart below shows the national summary of volatile organic compounds (VOCs)

emissions by source sector in the year 2002.

Figure A5.01. National volatile organic compounds emission by source sector in 2002.

Source: EPA 2002.

96

The map below shows relative emission density (tons per square mile) by

dividing counties into three groups, with the darker-shaded counties having higher

relative emission density.

Figure A5.02. Volatile organic compounds emission by municipalities of Puerto Rico in

2002.

Source: EPA 2002.

97

The graph below shows state-level emissions in Puerto Rico grouped by major

source sectors. The same information is also available for the individual counties below.

Figure A5.03. Volatile organic compounds emission by source sector in Puerto Rico in

2002.

Source: EPA 2002.

98

The graph below show’s relative VOC emission density (tons per square mile) in

Caguas, Puerto Rico.

Figure A5.04. Volatile organic compounds emission by source sector in Caguas, Puerto

Rico in 2002.

Source: EPA 2002.

99

Appendix Six

Hazardous air pollutants of greatest concern

Table A6. Hazardous air pollutants of greatest concern for exposure and health effects.

aCompounds suspected of inducing or exacerbating asthma.

Source: EPA 2000

Acetaldehydea Formaldehydea

Acreolina Hexachlorobenzene

Acrylonitrile Hydrazinea

Arsenic compounds Lead compounds

Benzenea Manganese compoundsa

Berylium compounds Mercury compounds

1,3-Butadiene Methylene chloride

Cadmium compoundsa Nickel compoundsa

Carbon tetrachloride Perchloroethylene

Chloroform Polychlorinated biphenyls

Chromium compoundsa Polycyclic organic matter

Coke oven emissionsa Propylene dichloride

1,3-Dichloropropene Quinoline

Dioxin 1,1,2,2-Tetrachloroethane

Ethylene dibromide Trichloroethylene

Ethylene dichoride Vinyl chloride

Ethylene oxidea

100

Appendix Seven

Volatile organic compounds emission sources

Table A7. Volatile Organic compounds emitted from building

materials and interior furnishings.

Source: Crinnion 2000.

Source Pollutant Emitted

Adhesives Alcohols

Amines

Benzene

Formaldehyde

Terpenes

Caulking Compounds Xylenes

Alcohols

Alkanes

Amines

Fomaldehyde

Methylketone

Xylenes

Benzene

Carpeting Alcohols

Alkanes

Formaldehyde

4-Methylbenzene

Styrene

Particle Board Alcohols

Alkanes

Amines

Benzene

3-Carene

Formaldehyde

Terpenes

Toluene

Tile and linoleum

Floor coverings

Wall coverings

Acetates

Alcohols

Alkanes

Amines

Benzene

Formaldehyde

Methyl styrene

Xylenes

Paints, stains,

varnishes

Acetates

Acrylates

Alcohols

Alkanes

Amines

Benzenes

Formaldehyde

101

Appendix Eight

List of elementary public schools in Caguas II District

Table A8. Total number of elementary public schools of Caguas II District, Puerto Rico.

Schools Zone Physical Address

(Caguas, PR 00725)

SU Mercedes Palma Rural Bo. San Salvador

SU Sandalio Marcano Rural Bo. Tomas De Castro 1

Bunker Rural Bo. Cañaboncito

Cipriano Manrique Rural Bo. Borinquen

Ramón Brugeras Rural Bda. Villa Esperanza

Cornelio Ayala Rural Bo. Borinquen

Concepción Méndez Cano (Conchita) Urban Urb. Turabo Gardens

José Mercado Urban Urb. Mariolga

Ave. Luis Muñoz Marin

Luis Munoz Rivera Urban Final Calle Muñoz Rivera

Paula Mojica Urban Urb. Villa Turabo

Rosa C. Benítez Urban Primera Sección

Urb. Villa del Rey

102

Appendix Nine

Instrumentation used

Figure A9. MiniRae® PID 2000 Instrumentation used for TVOC measurements.

Source: RAE Systems 2001.

103

Appendix Ten

Volatile Organic Compounds Detected By PID with a 10.6 eV Lamp

(Source: RAE Systems Inc.)

Acetaldehydea (ethanal); C2H4O

Acetic Anhydride (Acetic Acid)

Acetone

Acroleina (2-propenal); C3H4O

Acrylamidea; C3H5NO

Acrylonitrilea (2-propenenitrile); C3H3N

Allyl Alcohol

Allyl Chloride

Allyl Glycidyl Ether

Aminopyridine

Amyl Acetate

Amyl Alcohol

Anilinea (aminobenzene); C6H7N

Anisidine

Anisole

Benzenea; C6H6

Benzyl Alcohol

Benzyl Chloridea (a-chlorotoluene);

C7H7Cl

Bromoforma (tribromomethane); CHBr3

n-Bromopropane

Butadienea; C4H6

Butoxyethanol

Butyl Acetate

Butyle Acrylate

Butyl Alcohol

Butylamine

Butyl Cellosolve

Butyl Glycidyl Ether

Butyl Mercaptan

Camphor Vapor

Carbon Disulfidea; CS2

Cellosolve

Chloroacetaldehyde

Chloroacetophenone

Chlorobenzenea; C6H5Cl

Chloroprenea (2-chloro-1,3-butadiene);

C4H5Cl

Cresola; C7H8O

Crotonaldehyde

Cumenea (isopropylbenzene); C9Hl2

Cyclohexane

(aCompounds regulated by the US Environmental Protection Agency)

104

Continuation of Volatile Organic Compounds Detected By PID 10.6 eV Lamp

Cyclohexanol

Cyclohexanone

Cyclohexene

Cyclopentadiene

Diacetone Alcohol

Decane

Diazomethanea; CH2N2

Dichlorobenzenea; C6H4Cl2

Dichloroethyl Ether

Dichloroethylenea; C2H2Cl2

Dichlorvos

Diesel Fuel

Diethylaminoethanol

Diethylamine

Diglycidyl Ether

Diisobutyl Ketone

Diisopropylamine

N,N-Dimethylacetamide

Dimethylaminea; C2H6N2O

Dimethylanilinea; C8H11N

Dimethylformamidea; C3H7NO

Dimethylhydrazinea; C2H8N2

Dimethyl Methyl Phosphonate

Dimethylphthalate

Dimethyl Sulfoxide

Dioxane a (Diethylene oxide); C4H8O2

Diphenyl

Epichlorohydrina (l-chloro-2,3-epoxy

propane); C3H5ClO

Ethane

Ethanola; CH4O

Ethanolamine

Ethoxyethyl Acetate

Ethyl Acetate

Ethyl Acrylatea; C5H8O2

Ethyl Amyl Ketone

Ethyl Benzene

Ethyl Bromidea (bromomethane); CH3Br

Ethyl Butyl Ketone

Ethylamine

Ethylene Dibromidea (1,2-

dibromoethane); C2H4Br2

Ethylenediamine

Ethyleneiminea (aziridine); C2H5N

Ethyl Ether

Ethyl Hexyl Acrylate

Ethyl Lactate

Ethyl Mercaptan

(aCompounds regulated by the US Environmental Protection Agency)

105

Continuation of Volatile Organic Compounds Detected By PID 10.6 eV Lamp

Ethyl Silicate

Ethyl Sulfide

Furfural

Furfuyl Alcohol

Gasoline

Glycidol

Heptane

Hexanea; C6H14

Hexanone

Hexyl Acetate

Hydrogen Sulfide

Hydroquinone

Iodine

Isoamyl Acetate

Isobutyl Acetate

Isobutyl Alcohol

Isopar

Isophoronea; C9H14O

Isopropyl Acetate

Isopropyl Alcohol

Isopropyl Ether

Isopropylamine

Isopropyl Glycidyl Ether

JP-4, -5, -8

Kerosene

Ketene

Limonene

Mesityl Oxide

Methyl Acetate

Methyl Acetylene

Methyl Acrylate

Methyl Amyl Ketone

Methyl Bromidea (bromomethane);

CH3Br

Methyl Cellosolve

Methyl Ethyl Ketonea (2-butanone);

C4H8O

Methyl Ether

Methyl Hydrazine

Methyl Iodidea (iodomethane); CH3I

Methyl Isocyanatea; C2H3NO

Methyl Mercaptan

Methyl Methacrylatea; C5H8O2

N-Methyl Pyrrolidone

Methyl Styrene

Methylamine

Methylcyclohexane

Methylcyclohexanone

(aCompounds regulated by the US Environmental Protection Agency)

106

Continuation of Volatile Organic Compounds Detected By PID 10.6 eV Lamp

Methylcyclohexanol

Mineral Spirits

Monomethylaniline

Morpholine

Naphtha

Naphthalene Nitroaniline

Nitrobenzenea; C6H5NO2

Nitrochlorobenzene

Nitromethane

Nitrotoluene

Nonane

Norpar Octane

Pentane

Pentanone

Perchloroethylene

PGMEA

Phenola; C6H6O

Phenyl Ether

Phenylene Diamine

Phenylhydrazine

Phosphine

Phthalic Anhydride

Pinene

Propyl Acetate

Propyl Alcohol

Propylene Dichloridea (1,2-

dichloropropane); C3H6Cl2

Propylene Imine

Propylene Oxidea; C3H6O

Pyridine

Quinone

Stibine

Stoddard Solvent

Styrenea; C8H8

Tetrachloroethylenea; C2Cl4

Tetrahydrofuran

Toluenea; C7H8

Toluene diisocyanate

Toluidine

Toner Fluid

Trichloroethylenea; C2HCl3

Triethylaminea; C6H15N

Triethyl Borate

Triethyl Phosphate

Turpentine

Vinyl Bromidea (bromoethene); C2H3Br

Vinyl Chloridea (chloroethene); C2H3Cl

(aCompounds regulated by the US Environmental Protection Agency)

98

Continuation of Volatile Organic Compounds Detected By PID 10.6 eV Lamp

Vinylidene Chloridea (1,1-dichloroethylene); C2H2Cl2

Vinyl Cyclohexene

Vinylpyrrolidinone

Vinyl Toluene

White Spirit

Xylenea (isomer & mixtures); C8H10

(aCompounds regulated by the US Environmental Protection Agency)

108

Appendix Eleven

Volatile Organic Compounds Not Detected by PID

(Source: RAE Systems Inc.)

Acetonitrile

Carbon Dioxide

Carbon Monoxide

Freons

Hydrogen

Hydrogen Bromide

Hydrogen Chloride

Hydrogen Cyanide

Hydrogen Fluoride

Hydrogen Peroxide

Methane

Nitric Acid

Nitrogen

Oxygen

Ozone

Sulfur Dioxide

Sulfuric Acid

Vikane (Sulfuryl Fluoride)

Water

109

Appendix Twelve

Aerial photographs of the school studied

Below can be found aerial photographs of the schools studied with a simple

outline of what is around the school.

Figure A10.01. Aerial photograph of the rural School 001.

Source: Google Earth 2007.

110

Figure A10.02. Aerial photograph of the urban School 002.

Source: Google Earth 2007.

111

Figure A10.03. Aerial photograph of the urban School 003.

Source: Google Earth 2007.

112

Figure A10.04. Aerial photograph of the rural School 004.

Source: Google Earth 2007.

113

Appendix Thirteen

Meteorological data of Caguas, Puerto Rico

These are the meteorological data for the days of the TVOC measurement study

from the Caguas station that is part of the MADIS Project in Puerto Rico. In the tables

below are the daily averages and weakly averages for the month of February 2008.

Table A14.01. Meteorological data for the days of indoor and outdoor sampling in

schools.

School Type of

Sampling

Temperature

(°C)

Humidity

(%)

Pressure

(mmHg)

Wind Velocity

(km/h)

001

Indoor 24.8 79 760.48 3.7

Outdoor 24.6 71 759.46 3.3

002 Indoor 24.5 74 759.97 4.6

Outdoor 23.6 78 759.97 4.4

003 Indoor 26.6 74 761.24 6.1

Outdoor 26.0 66 760.48 4.1

004 Indoor 23.6 79 760.98 4.0

Outdoor 23.1 80 762.25 2.9

114

Table A14.02. Weekly meteorological data for the month of February 2008.

Day Temperature

(°C)

Humidity

(%)

Pressure

(in.)

Wind Velocity

(km/h)

1 22.3 77 29.85 5.2

2 21.3 85 29.90 1.4

3 23.4 76 29.95 3.3

4 24.1 74 29.96 3.2

5 24.0 73 29.98 3.0

6 23.4 80 29.97 2.1

7 24.0 78 29.94 4.6

8 24.8 79 29.94 3.7

9 24.5 76 29.92 4.6

10 24.9 75 29.90 4.3

11 24.6 71 29.90 3.3

12 24.5 74 29.92 4.6

13 23.6 78 29.92 4.4

14 26.6 74 29.97 6.1

15 26.0 66 29.94 4.1

16 24.3 72 29.88 4.1

17 21.4 85 29.63 2.1

18 23.6 79 29.96 4.0

19 23.1 80 30.01 2.9

20 24.3 72 29.97 3.3

115

Continuation of TableA14.02. Weekly meteorological data for the month of February

2008.

Day

Temperature

(°C)

Humidity

(%)

Pressure

(in.)

Wind Velocity

(km/h)

21 24.8 72 29.97 3.3

22 24.6 72 29.97 4.1

23 24.2 76 29.99 3.6

24 24.2 74 29.96 3.4

25 25.4 73 29.91 3.8

26 24.8 75 29.91 4.1

27 22.3 82 29.90 2.2

Total Average

24.0

76

29.93

3.6

Table A14.03. Meteorological data averages for each week in February 2008.

Week

Temperature

(°C)

Humidity

(%)

Pressure

(in.)

Wind Velocity

(km/h)

1 21.8 81 29.87 3.3 2 24.0 76 29.95 3.5 3 24.9 73 29.92 4.4 4 23.7 76 29.93 3.3 5

24.1

76

29.92

3.4

116

Appendix Fourteen

Wind Resources of Puerto Rico

Figure A15.01. Wind Resources for Puerto Rico.

Source: AWS Truewind 2007.

117

Appendix Fifteen

Potential air quality problems in schools

Some problems that can cause decreased air quality are seen in the

photographs below. These photographs were taken in the schools studied and all of the

schools showed some degree of the same problems.

Sample one

Figure A11.01. Storage problem in classrooms.

118

Sample two

Figure A11.02. Electronic accumulation storage in classrooms.

119

Sample three

Figure A11.03. Mold growth outdoors problem in the school area.

120

Sample four

Figure A11.04. Sewers in front of the schools which can give off gases that affect air

quality.

121

Sample five

Figure A11.05. Construction of new school facilities during school hours.

122

Appendix Sixteen

Summarized climatologic day data sample

Table A12.01. Climatologic data results for school 001 from day of sample.

Parameters Indoor Outdoor

Temperature (°C) Mean 25 ± 1 26 ± 2

Max 27.1 28.9

Min 22.8 21.7

% Relative Humidity Mean 75 ± 5 64 ± 10

Max 85.3 80.8

Min 66.1 49.2

Wind Velocity Range

(m/s)

0.0 0.0-2.6

Observations Sunny day. There are cats

and dogs in the school

establishment.

Cloudy and sunny

day. There are

cats and dogs in

the school

establishment.

There was a

school bus picking

up students in the

afternoon.

123

Table A12.02. Climatologic data results for school 002 from day of sample.

Parameters Indoor Outdoor

Temperature (°C) Mean 22.8 ± 0.8 27 ± 1

Max 25.9 28.9

Min 22.4 24.0

%Relative Humidity Mean 61 ± 3 63 ± 7

Max 67.9 78.7

Min 56.9 52.7

Wind Velocity Range (m/s) 0.0 0.0-2.0

Observations Sunny day. The

classroom has air

conditioning and

collides with the

school parking and

with a cleaning area.

There is a lot of

storage. The air

conditioning was on

when the equipment

was started and the

air conditioning was

off when the

equipment was

acquired.

Cloudy day. Close

to the sample area

is a water hose and

a plastic basin

which they use to

clean. Also outside

the parameters of

the school are two

sewers with foul

odor.

124

Table A12.03. Climatologic data results for school 003 from day of sample.

Parameters Indoor Outdoor

Temperature (°C) Mean 27 ± 12 32 ± 4

Max 28.9 41.2

Min 24.9 22.4

% Relative Humidity Mean 62 ± 8 51 ± 12

Max 81.1 81.1

Min 51.8 31.2

Wind Velocity Range

(m/s)

0.0 0.4-0.8

Observations Cloudy day. The sample

classroom has marker

boards and chalk boards.

Also there are computers

which are not in use.

There was a little get

together party in the

afternoon.

Rainy day. The

sample was

taken close to

the school’s

parking lot

which collides

with a

mechanical

college. The

day of sampling

there were no

college classes.

125

Table A12.04. Climatologic data results for school 004 from day of sample.

Parameters Indoor Outdoor

Temperature (°C) Mean 27 ± 2 30 ± 3

Max 30.1 40.3

Min 23.6 27.3

% Relative Humidity Mean 61 ± 12 47 ± 7

Max 82.3 56.6

Min 42.9 29.3

Wind Velocity Range

(m/s)

0.0-0.5 0.3-1.1

Observations It was a rainy morning and

a cloudy afternoon. In the

morning there were

starting to clean the

classroom and when the

class started, the air

conditioning was turned

on.

It was a sunny

and cloudy day.

There doesn’t

seem to be any

traffic. We can

perceive a shift

of wind

direction during

the day.

126

Appendix Seventeen

Summarized TVOC measurement results data

Table A13.01. Summarized indoor and outdoor TVOC results measurements for the

schools studied (n=5560).

School Indoor (mg/m3) Outdoor (mg/m3) Mean

Ratio (I/O) Mean Max Min Mean Max Min

001 0 ± 0 0.0 0.0 0 ± 0 0.0 0.0 0.0

002 0.0 ± 0.6 47.20 0.0 0 ± 5 76.50 0.0 0

003 0.0 ± 0.3 22.07 0.0 0 ± 2 126.88 0.0 0

004 18 ± 31 468.91 0.0 5 ± 16 95.16 0.0 3.6

Table A13.02. Summarized indoor and outdoor TVOC comparison measurements for

urban schools studied.

School Indoor (mg/m3) Outdoor (mg/m3) Mean

Ratio (I/O) Mean Max Min Mean Max Min

001 0 ± 0 0.0 0.0 0 ± 0 0.0 0.0 0.0

004 18 ± 31 468.91 0.0 5 ± 16 95.16 0.0 3.6

127

Table A13.03. Summarized indoor and outdoor TVOC comparison measurements for

rural schools studied.

School Indoor (mg/m3) Outdoor (mg/m3) Mean

Ratio (I/O) Mean Max Min Mean Max Min

002 0.0 ± 0.6 47.20 0.0 0 ± 5 76.50 0.0 0

003 0.0 ± 0.3 22.07 0.0 0 ± 2 126.88 0.0 0

128

Appendix Eighteen

Glossary terms

Ambient air – the air immediately around us.

Anthropogenic emissions - emissions of particles or substances resulting from human

activities, such as industry and agriculture.

Asthma – a distressing disease characterized by shortness of breath, wheezing and

bronchial muscle spasm.

CAA - Clean Air Act. Federal law mandating and enforcing toxic emissions standards for

stationary and mobile sources.

Cancer – is an invasive, out of control cell growth that results in malignant tumors.

Carcinogen – substance that causes cancer.

CDC - Center of Disease Control

CFCs - Chlorofluorocarbons, compounds containing chlorine and fluorine bonds that

have been used as refrigerants. These compounds have been shown to deplete

stratospheric ozone and can also act as greenhouse gases.

Chronic effects – long-lasting results of exposure to a toxin; can be a single, acute

exposure or a continuous low level exposure.

Chronic Exposure - exposure to a substance over a long period of time.

Climate - the long term average condition of the weather in a given area.

Climate change: the slow variations of climatic characteristics over time at a given

place. Usually refers to the change of climate which is attributed directly or

indirectly to human activity that alters the composition of the global atmosphere

and which is, in addition to natural climate variability, observed over comparable

periods.

129

Climate system: the totality of the atmosphere, hydrosphere, biosphere, and geosphere

and their interactions that characterize the average and extreme conditions of the

atmosphere over a long period of time at any one place or region of the earth's

surface.

Compound – a molecule made up of two or more kinds of atoms held together by

chemical bonds.

Contaminant: any biological, chemical, physical or radiological substance that has an

negative effect on air, soil or water.

Disease – a deleterious change in the body’s condition in response to destabilizing

factors.

Emissions - the release of gaseous substances into the atmosphere.

Emission standards – regulations for restricting the amounts of air pollutants that ca be

released from specific point sources.

Environment – the circumstances or conditions that surround an organism or group of

organisms.

EPA - Environmental Protection Agency U.S.. Primary federal agency responsible for

enforcement of federal laws protecting the environment.

Global warming - the warming of the earth's surface, driven by either natural or

anthropogenic forces.

Greenhouse gases - gases that absorb atmospheric and solar infrared radiation and

reflect it back to earth to increase global warming, causing climate change.

Ground-level ozone (tropospheric ozone): Ozone (O3) that occurs near the surface of

the Earth. In pollution it causes concern because of its toxic effects.

Hazardous – describes chemicals that are dangerous including flammables, explosives,

irritants, sensitizers, acids and caustics; may be relative harmless in diluted

concentrations.

130

Hazardous Air Pollutant - a pollutant to which no ambient quality standard is applicable

and that may cause or contribute to an increase in mortality or in serious illness.

Half-life - also referred to as decay constant; the term is used to quantify a first-order

exponential decay process.

Health – a state of physical and emotional well-being the absence of diseases or

ailment.

Inhalation - the breathing of airborne contaminants in the form of vapors, gases, mists,

or particulates may produce harmful effects.

Kyoto Protocol – is an international agreement to reduce greenhouse gas emission.

MADIS - Meteorological Assimilation Data Ingest System is dedicated toward making

value-added data available from the National Oceanic and Atmospheric

Administration's.

Monitoring - the process of measuring certain environmental parameters on a real-time

basis for spatial and time variations. For example, air monitoring may be

conducted with direct-reading instruments to indicate relative changes in air

contaminant concentrations at various times.

Morbidity – illness or disease.

Mortality – death rate in a population; the probability of dying.

Mutagens – agent such as chemicals or radiation that damages or alters genetic

materials in cells.

Mutation – a change either spontaneous or by external factors, in the genetic materials

for a cell.

NAAQS – National Ambient Air Quality Standard; federal standards specifying the

maximum allowable levels for regulated pollutants in ambient air.

Neurotoxins – toxic substances that specifically poison nerve cells.

NIOSH - National Institute of Occupational Safety and Health

131

Nitrogen oxides – is a highly reactive gas from when nitrogen-containing compounds

are oxidized.

NOAA - National Oceanic and Atmospheric Administration

OSHA - Occupational Safety and Health. Act of 1970, oversees and regulates work

place health and safety.

Ozone: a gas composed of three atoms of oxygen (03). Ozone partially filters certain

wavelengths of ultraviolet light from the Earth. Ozone is a desirable gas in the

stratosphere, but in high concentrations at ground level, it is toxic to living

organisms.

Ozone layer (stratospheric ozone): ozone that is formed in the stratosphere from the

conversion of oxygen molecules by solar radiation. Ozone absorbs much

ultraviolet radiation and prevents it from reaching the Earth.

Photochemical oxidants – products of secondary atmosphere reactions.

PID – Photo Ionization Detector

Pollutant - legally, any dredged spoil, solid waste, incinerator residue, filter backwash,

sewage, garbage sewage sludge, munitions, chemical wastes, biological

materials, radioactive materials (except those regulated under the Atomic Energy

Act, heat, wrecked or discharged into water. From a practical perspective, any

substance or mixture which after release into the environment and upon

exposure to any organism will or may reasonable be anticipated to cause

adverse effects in such organisms or their offspring.

Pollution – activities that alter the environment in undesirable ways.

PR – Puerto Rico

Relative humidity – at any given temperature, a comparison of the actual water content

of the air with the amount of water that could be held at saturation.

Smog – term used to describe photochemical pollution products.

132

Source - any process, activity or mechanism which releases contaminants in the

atmosphere.

Temperature – a measurement of the speed of motion of a typical atom or molecule in a

substance.

Toxic - harmful to living organisms.

TVL – Threshold Value Limit

TVOC – Total Volatile Organic Compounds.

Vapor - an air dispersion of molecules of a substance that is liquid or solid in its normal

physical state, at standard temperature and pressure.

VOC – Volatile Organic Compounds; organic compounds that evaporate readily and

exists as gasses in the air.

Weather – description of the physical conditions at the atmosphere.