Indoor Air Pollution

Indoor air pollution

It refers to the physical, chemical and biological

characteristics of air in the indoor environment within a home,

building, an institution or a commercial facility.

Is (Indoor air quality) IAQ Important?

• 30% of newly constructed or remodeled facilities have IAQproblems

• Indoor contaminants are responsible for half of all illnesses

• Liability issues

Why is There an Increase in IAQ problems?

• More time indoors

• More chemical pollutants in buildings

• Tighter buildings and reduced ventilation

• Deferred maintenance

Common Health Effects of Indoor Contaminants

• Eye, nose and throat irritation

• Coughing and sneezing

• Headaches

• Fatigue

• Irritability

• Allergies, sinus congestion

• Dizziness

• Difficulty in concentrating

Factors influencing IAQ

• Rate of exchange of air with outdoor air.

• Concentration of pollutants in outdoor air.

• Rate of emission of indoor sources.

• Rate of infiltration from soil gases

• Rate of removal in indoor environment

Sick Building Syndrome

• Symptoms include eye, nose and throat irritation, headache,allergies, fatigue

• 20% or more of occupants experience same symptoms

• No medically diagnosable symptoms

• Complaints persist for more than two weeks

• Symptoms often lessen after person leaves building

Building-Related Illness

• Clinically defined illness or disease

o E.g. Asthma, Legionaires’ Disease, Hypersensitivity Pneumonitis

• Symptoms depend on the disease

Regulations and Standards

• Outdoor airborne contaminant levels

o Environmental Protection Agency (EPA) o National Ambient Air Quality Standards (NAAQS)

• Indoor airborne contaminant levels in the workplace

o Occupational Safety and Health Administration (OSHA)

• ASHRAE Standards 62-1989, 62-2001, 62-2004, 62.1-2007

ASHRAE Ventilation Standards

• ASHRAE 62-1989 – Objective of ventilation is satisfaction of 80% of inhabitants

OSHA Permissible Exposure Levels (PELs)

• “Time-weighted average concentrations that must not beexceeded during any 8-hour work shift of a 40-hourworkweek”

• Legally enforceable

• Measured in parts per million (ppm) or milligrams per cubicmeter (mg/m3)

Threshold Limit Values (TLVs)

• “Time-weighted average concentration for a conventional 8-hour workday and a 40-hour workweek, to which it is believedthat nearly all workers can be repeatedly exposed, day afterday, without adverse effect”

• Guidelines

• Generally more conservative than PELs

Sources of Indoor air pollutionPollutant Source

Combustion gases – CO, NO Combustion- furnace, cooking stove etc.

VOCs Coatings, wall and floor coverings,furnishings

Formaldehyde Out-gassing of pressed wood, insulationfoam

Pesticides Household products

Particulate matter Combustion

Biological agents- moulds, spores Contaminated ventilation systems, pets

Environmental tobacco smoke Smoking in building

Radon Infiltration from soil beneath structure

Asbestos Construction coatings, tile, insulation

Source of Indoor air pollution• May be inside the building or they may be transported into the

interior space from the outside.

• Emission of organic gases are higher with high temperatureand humidity but decreases with age of the structure orfurnishings.

• Natural gas for cooking and kerosene space heaters releaseNO and CO2 even when operating properly.

• Moulds may grow in the ventilation duct and may spreadthroughout the building.

Problem - Causing Compounds

• Chemicals

• Combustion products

• Respirable particles and gases

• Biological aerosols

CHEMICALS

Volatile Organic Compounds (VOCs)

• Carbon-containing compounds that evaporate rapidly

• Exampleso Benzene

o Toluene

o Styrene

o Perchloroethylene

o Pesticides

Volatile Organic Compounds(Sources)

• Paints, stains, varnishes• Waxes• Polishes• Solvents• Pesticides• Adhesives• Wood preservatives• Cleansers

• Lubricants• Air fresheners• Fuels• Plastics• Copy machines, printers• Tobacco products • Perfumes• Dry cleaned clothing

PESTICIDES - Symptoms

• Headache• Dizziness• Lack of coordination• Nervousness• Irritability• Insomnia• Confusion• Loss of concentration• Speech difficulties

• Depression• Impaired judgment• Memory deficits• Visual disturbances• ECG changes• Weakness• Fatigue• Paralysis

Formaldehyde

• Used in plywood, paneling, particleboard, wallboard,fiberglass, adhesives

• Sometimes in ceiling tiles, wallpaper, furniture, draperies,clothing

• Even low levels can cause difficulties in breathing, burning ofeyes nose and throat, coughing; a human carcinogen

• PEL 0.75 ppm; TLV ceiling limit 0.3 ppm

Perchloroethylene

• Solvent used in dry cleaning, metal cleaning and degreasing

• Can cause irritation of eyes, nose, throat and skin, liver andkidney damage, CNS depression

• Considered an animal carcinogen and probable humancarcinogen

• PEL 100 ppm; TLV 25 ppm

COMBUSTION PRODUCTS

Combustion Products

• Carbon monoxide (CO)

• Oxides of nitrogen (NOx)

• Oxides of sulfur (SOx)

• Carbon dioxide (CO2)

• Polycyclic Aromatic Hydrocarbons (PAH)

• Tobacco Smoke components

Carbon Monoxide (CO)

• Colorless, odorless, tasteless poisonous gas

• Produced as a by-product of combustion

• Deprives the body of oxygen by binding to blood hemoglobinand displacing oxygen molecules

Carbon Monoxide (CO)

• Symptoms are headache, dizziness, drowsiness and nausea

• Severe exposure results in vomiting, collapse, coma anddeath

• PEL 50 ppm; TLV 25 ppm

• Body systems most affected are the brain, the heart, and thedeveloping fetus

Carbon Monoxide (CO)

• Low levels of exposure - more frequent attacks of angina,reduced athletic performance, heart attacks

• Moderate exposures - loss of attentiveness, decreased visualperception, manual dexterity, learning ability and driving ability

• Smoking – cause of the greatest human exposure

Carbon Dioxide (CO2)

• Colorless, odorless, tasteless gas at room temperature

• Present in exhaled human breath

• Combustion by-product

• Naturally present in an unpolluted environment at about 300ppm

Carbon Dioxide (CO2)

• CO2 levels above 800 ppm may indicate inadequateventilation

• ASHRAE recommended indoor air quality limit for CO2 is1000 ppm

• PEL 5000 ppm; TLV 5000 ppm

Tobacco Smoke

• Respirable particles and gases, including benzene, carbonmonoxide, formaldehyde, hydrogen cyanide, ammonia andVOCs

• Side stream smoke from cigarette contains higherconcentrations of some toxic and carcinogenic substancesthan mainstream smoke inhaled by smoker

Tobacco Smoke

• Causes lung cancer in nonsmokers as well as smokers

• Increased respiratory infections in children

• Irritation of upper respiratory tract, coughing, wheezing,sneezing, headache, sinus problems, asthma, increasedcardiovascular risk

RESPIRABLE PARTICLES & GASES

Respirable Particles & Gases

• Asbestos• Fiberglass• Silica• Metal dust• Tobacco smoke components• Organic dust

o Polleno Mold sporeso Paper dust

• Radon

Asbestos

• Group of indestructable highly fibrous minerals

• Separated fibers are long, thin, flexible, heat resistant, able tobe spun and woven

• Health effects: lung cancer, mesothelioma, asbestosis, pleuralplaques

• Airborne concentration in homes and schools 30 to 6,000fibers/m3

• PEL 0.1 fiber/cc; TLV 0.1 fiber/cc

Lead

• Indestructable, non-biodegradable, adaptable metal

• Romans used lead to line aqueducts, as mortar, in plumbingand to sweeten wine

• Was used in gasoline, batteries, paints, ceramic glazes,ammunition, fishing sinkers, metal toys

Lead

• Three quarters of the nation’s housing contains lead-basedpaint

• Children are at greater risk for lead poisoning than adults

o Hand to mouth activity

o Developing body systems more easily affected

o Action level is 10 micrograms per deciliter (μg/dl)

Lead – Chronic Exposure Health Effects

• Loss of appetite• Metallic taste in mouth• Anxiety• Constipation• Nausea• Palor• Excessive tiredness• Weakness• Insomnia

• Headache• Nervous irritability• Muscle and joint pain or

soreness• Fine tremors• Numbness• Dizziness• Hyperactivity• Colic, with severe

abdominal pain

Chronic Effects of Lead Poisoning in Children

• Fetal development abnormalities

• Decreased intelligence

• Slowed neurological development

• Reading and learning problems

• Reduced attention span

Chronic Effects of Lead Poisoning in Children (cont.)

• Hearing loss

• Behavioral problems such as hyperactivity

• Stunted growth

• Permanent damage to the brain, nervous system and kidneys

Sources of Potential Exposure to Lead

• Lead-based paint

• Lead-contaminated dust

• Lead-contaminated soil

• Candle wicks

• Pewter and silver products

• Lead crystal

• Some lead-glazed pottery and porcelain

• Some imported mini-blinds

Radon

• Naturally occurring radioactive gas

• Colorless, odorless, tasteless

• Causes no symptoms of irritation or discomfort

• No early signs of exposure

• Testing a building is the only way to evaluate exposure

• Action level is 4 picocuries per liter (pCi/L)

Radon Health Effects

• Damage by alpha radiation to tissue of lungs and respiratorytract

• 20,000 lung cancer deaths per year

• Non-smokers risk of lung cancer at 4 pCi/L is 2 in 1000

• Smokers risk of lung cancer at 4 pCi/L is 20 in 1000

Testing for Radon

• Test in lowest livable area in building

• Close all doors and windows 12 hours before testing

• Do not test in kitchen or bathroom

• Place monitor at least 20 inches above floor

• Test during coldest months of the year

Radon Control Measures

• Increasing the ventilation in the building

• Sealing the foundation

• Sub-slab depressurization

Sub-Slab Depressurization

BIOAEROSOLS

Bioaerosols

• Substances that are living or were released from a livingorganism

• Exampleso Bacteriao Fungio Polleno Viruseso Dust mites

Dust Mites

Dust Mites

• Microscopic relatives of spiders

• Feed on dead skin scales and other organic debris

• 2,000,000 in an average bed

• Dust mite feces - a common allergen

• Prefer relative humidity level above 55%

Viruses

• Smallest and simplest of all life forms

• Depend completely on their hosts for reproduction

• Continually undergo evolutionary change

• Exampleso Influenzao HIVo Rhinovirus

Bacteria

• Single-celled prokaryotic organisms

• Most are very small spheres, rods or filaments

• Reproduce by simple cell division

• Some produce endospores, which are extremely resistant toharsh conditions

• A few require living hosts

Bacteria in Indoor Environments

• Higher concentrations indoors than outdoors

• Majority of bacteria in air are shed from human skin andrespiratory tracts

• Examples of infectious bacteriao Legionella spp.o Staphlococcus aureuso Mycobacterium tuberculosis

Mold

Mold? Where??

Mold on ceiling and walls

Mold in a closet

Mold in air duct

Fungi as Food• Mushrooms• Soy sauce• Yeast• Bread• Cheese• Wine• Beer

Mucor species

Penicillium species

Aspergillus niger

Aspergillus fumigatus

Growing Conditions

• Optimum water activity o Above 0.90 in substrate, for most species

• Optimum temperature range o 56°F to 86°F, for most species

• Light o Inhibits growth of some types of moldso Stimulates spore production in many species

General Health Effects

• Sinus congestion

• Sneezing

• Coughing

• Eye irritation

• Asthma

• Bronchitis

• Hypersensitivity pneumonitis

• Infectious diseases, e.g. ringworm, athletes foot, nailinfections, Histoplasmosis, Valley Fever

Exchange methods of air

Air is exchanged by several ways.

Natural ventilation: movement of air through doors, windows andvents.

Mechanical ventilation : fans, heating and air conditioningsystem.

Infiltration and Exfiltration: undesirable movement of air in andout of the structure.

Analysis of IAQ

• Techniques for analyzing IAQ include collection of airsamples, collection of samples on building surfaces andcomputer modelling of flow inside buildings.

• The resulting samples can be analysed for mould, bacteria ,chemicals or other stressors.

• These investigations can lead to understanding of the sourcesand help in designing the reduction strategies.

How to improve IAQ• Understand the role of Green Cleaning: Citrus based solvents

and pine-based solvents react with ozone to form aldehydesand acidic aerosols. Do not use ‘green’ cleaning products ifoutdoor ozone concentration is . 50 ppb. Ozone can beremoved from outdoor air by filtration with carbon.

• Install an air purifier but ozone-based air cleaners are notadvised.

• Introducing plants to reduce thee levels of indoor air pollutionis only minimally effective.

• Use natural household cleaning products and reduceexposure to potentially toxic airborne substances.

How to improve IAQ (contd..)

• Use natural pest control techniques indoors wheneverpossible. Banish pesticides from your garden.

• Keep your plumbing traps filled with water to help preventsewer gas from entering the building.

• Regularly clean the vents in your kitchen, bathroom and dryer.

• Avoid smoking in indoor areas.

• Avoid or reduce biological contaminants by maintaininghumidifiers, dehumidifiers and air conditioners; emptyingwater trays in dehumidifiers, AC’s, and refrigeratorsfrequently; routinely clean bedding and pet items.

How to improve IAQ (contd..)

• Prevent CO exposure by keeping gas appliances properlyserviced, having your central heating system inspected andcleaned yearly, and never idling your car inside an attachedgarage.

• Change filters on central cooling and heating systems and aircleaners according to manufacturer’s association.

• Test your home for radon. Radon can seep from contaminatedearth and rock under the home, or from well water andbuilding materials. Easy, do-it-yourself kits can be purchasedat hardware outlets.

• Ensure good ventilation

How to improve IAQ (contd..)

• Have any air-conditioning systems inspected regularly toverify that there is no internal contamination build upcontributing to poor indoor air quality.

• Keep crawl spaces, basements, and soil immediately aroundthe house clean and dry.