g. tyler miller’s living in the environment 14 th edition chapter 20 air pollution

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G. Tyler Miller’s

Living in the Environment

14th Edition

Chapter 20

Air Pollution

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Figure 20-1Page 433

Case Study: When is a Lichen Like a Canary

Key ConceptsKey Concepts

Structure and composition of the atmosphere Structure and composition of the atmosphere

Types and sources of outdoor air pollution Types and sources of outdoor air pollution

Types, formation, and effects of smog Types, formation, and effects of smog

Sources and effects of acid deposition Sources and effects of acid deposition

Effects of air pollution Effects of air pollution

Prevention and control of air pollution Prevention and control of air pollution

44

Earth’s AtmosphereEarth’s AtmosphereEarth’s AtmosphereEarth’s Atmosphere

Compared to the size of the Earth (12000 km)

The atmosphere is very thin (120 km)or

(75 miles)

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www.gsfc.nasa.gov/gsfc/earth/pinatuboimages.htm

http://www.gsfc.nasa.gov/gsfc/earth/pinatuboimages.htm

http://www.gsfc.nasa.gov/gsfc/earth/pinatuboimages.htm

55

If theIf the EarthEarth is is compared to thiscompared to this

OrangeOrange

the Earth’s the Earth’s atmosphere atmosphere would be would be

thinner than the thinner than the layer of layer of

pesticide onpesticide on

this Orange’s this Orange’s surfacesurface

Two Atmosphere LayersTwo Atmosphere LayersTwo Atmosphere LayersTwo Atmosphere Layers• Stratosphere is above the TroposphereStratosphere is above the Troposphere

– Ozone Layer blocks UV radiationOzone Layer blocks UV radiation

• Troposphere is where we liveTroposphere is where we live– Weather occurs hereWeather occurs here– 78% Nitrogen, 21% Oxygen, 0.01%-4% water vapor, less 78% Nitrogen, 21% Oxygen, 0.01%-4% water vapor, less

than 1% Argon, 0.038% Carbon dioxide and trace amounts than 1% Argon, 0.038% Carbon dioxide and trace amounts of several other gasesof several other gases

– 72% of all air is below the cruising altitude of commercial 72% of all air is below the cruising altitude of commercial airliners (33000 ft)airliners (33000 ft)

Atmospheric pressure (millibars)0 200 400 600 800 1,000

120

110

100

90

80

70

60

50

40

30

20

10

0(Sea

Level)–80 –40 0 40 80 120

Pressure = 1,000millibars atground levelTemperature (˚C)

Alt

itu

de

(kilo

met

ers)

Alt

itu

de

(mile

s)

75

65

55

45

35

25

15

5

Thermosphere

Heating via ozone

Mesosphere50 mi.

Stratosphere31 mi.

Ozone “layer”Heating from the earth

Troposphere11 mi.

Temperature

Pressure

Mesopause

Stratopause

Tropopause

O3 -The Good, the Bad, and the Ugly

O3 -The Good

(15 - 40 km) blocks solar UV<290 nm

Beneficial Ozone that forms in the stratosphere protects life on earth by filtering out most of the incoming harmful UV radiation emitted by the sun

O3 -The Bad

6-10 km : greenhouse gas absorbs IR emitted by Earth

O3 →O3 (v=1)

Harmful or Photochemical ozone forms in the troposphere when various air pollutants undergo chemical reactions under the influence of sunlight. Ozone in this atmosphere near the earth’s surface damages plants, lung tissue, and some materials such as rubber.

O3 -The Ugly

part of smog (bad, too)

Alt

itu

de

(k

ilom

ete

rs)

Ozone concentration (ppm)

Alt

itu

de

(m

iles)Stratospheric ozone

Stratosphere

Troposphere

40

35

30

25

20

15

10

5

00 5 10 15 20

0

5

10

15

20

25

Photochemical ozone

20-2 Outdoor Air Pollution20-2 Outdoor Air Pollution

• Air pollution is the presence of chemicals in the atmosphere in concentrations high enough to affect climate and harm organisms and material.

• Outdoor air pollutants come mostly from – Natural sources (dust, VOC, decay of plants,

forest fires, volcanic eruption, and sea spray)– Burning fossil fuels

• Motor vehicles• Power and industrial plants

Table 20-1Page 436

Table 20-1 Major Classes of Air Pollutants

Class

Carbon oxides

Sulfur oxides

Nitrogen oxides

Volatile organic compounds (VOCs)

Suspended particulate matter (SPM)

Photochemical oxidants

Radioactive substances

Hazardous air pollutants (HAPs), which cause health effects such as cancer, birth defects, and nervous system problems

Examples

Carbon monoxide (CO) and carbon dioxide (CO2)

Sulfur dioxide (SO2) and sulfur trioxide (SO3)

Nitric oxide (NO), nitrogen dioxide (NO2), nitrous oxide (N2O) (NO and NO2 often are lumped together and labeled NOx)

Methane (CH4), propane (C3H8), chlorofluorocarbons (CFCs)

Solid particles (dust, soot, asbestos, lead, nitrate, and sulfate salts), liquid droplets (sulfuric acid, PCBs, dioxins, and pesticides)

Ozone (O3), peroxyacyl nitrates (PANs), hydrogen peroxide(H2O2), aldehydes

Radon-222, iodine-131, strontium-90, plutonium-239 (Table 3-1, p. 49)

Carbon tetrachloride (CCl4), methyl chloride (CH3Cl), chloroform (CHCl3), benzene (C6H6), ethylene dibromide (C2H2Br2), formaldehyde (CH2O2)

Primary Pollutants

Secondary Pollutants

Sources NaturalStationary

CO CO2

SO2 NO NO2

Most hydrocarbons

Most suspendedparticles

SO3

HNO3 H2SO4

H2O2 O3 PANs

Most and saltsNO3–

Mobile

SO42 –

Major Sources of Primary PollutantsMajor Sources of Primary PollutantsStationary Sources• Combustion of fuels for power and heat –

Power Plants• Other burning such as Wood & crop burning

or forest fires• Industrial/ commercial processes• Solvents and aerosolsMobile Sources• Highway: cars, trucks, buses and motorcycles• Off-highway: aircraft, boats, locomotives,

farm equipment, RVs, construction machinery, and lawn mowers

54 million metric tons from mobile sources in 1990

Human Impact on AtmosphereHuman Impact on Atmosphere

• Burning Fossil Fuels

• Using Nitrogen fertilizers and burning fossil fuels

• Refining petroleum and burning fossil fuels

• Manufacturing

Adds CO2 and O3 to troposphere

Global Warming Altering Climates Produces Acid Rain Releases NO, NO2, N2O, and NH3 into

troposphere Produces acid rain Releases SO2 into troposphere

Releases toxic heavy metals (Pb, Cd, and As) into troposphere

www.dr4.cnrs.fr/gif-2000/ air/products.html

http://www.dr4.cnrs.fr/gif-2000/air/products.html

Criteria Air PollutantsCriteria Air PollutantsEPA uses six "criteria pollutants" as indicators of air quality

1. Nitrogen Dioxide: NO2

2. Ozone: ground level O3

3. Carbon monoxide: CO

4. Lead: Pb

5. Particulate Matter: PM10 (PM 2.5)

6. Sulfur Dioxide: SO2

• Volatile Organic Compounds: (VOCs)

EPA established for each concentrations above which adverse effects on health may occur

CARBON MONOXIDE (CO)

Description: Colorless, odorless gas that is poisonous to air-breathing animals; forms during the incomplete combustion of carbon-containing fuels (2 C + O2 2 CO).

Major human sources: Cigarette smoking (p. 409), incompleteburning of fossil fuels. About 77% (95% in cities)comes from motor vehicle exhaust.

Health effects: Reacts with hemoglobin in red blood cells and reduces the ability of blood to bring oxygen to body cells and tissues. This impairs perception and thinking; slows reflexes; causes headaches, drowsiness, dizziness, and nausea; can trigger heart attacks and angina; damages the development of fetuses and young children; and aggravates chronic bronchitis, emphysema, and anemia. At high levels it causes collapse, coma, irreversible brain cell damage, and death.

Table 20-2 Major Outdoor Air Pollutants

•EPA Standard: 9 ppm

Table 20-2Page 438Table 20-2Page 438Table 20-2 Major Outdoor Air Pollutants

NITROGEN DIOXIDE (NO2)

Description: Reddish-brown irritating gas that gives photochemical smog its brownish color; in the atmosphere can be converted to nitric acid (HNO3), a major component of acid deposition.

Major human sources: Fossil fuel burning in motor vehicles (49%) and power and industrial plants (49%).

Health effects: Lung irritation and damage; aggravates asthma and chronic bronchitis; increases susceptibility to respiratory infections such as theflu and common colds (especially in young children and older adults).

Environmental effects: Reduces visibility; acid deposition of HNO3 can damage trees, soils, and aquatic life in lakes.

Property damage: HNO3 can corrode metals and eat away stone on buildings, statues, and monuments; NO2 can damage fabrics.

•EPA Standard: 0.053 ppm


SULFUR DIOXIDE (SO2)

Description: Colorless, irritating; forms mostly from the combustion of sulfur containing fossil fuels such as coal and oil (S + O2 SO2); in the atmospherecan be converted to sulfuric acid (H2SO4), a major component of acid deposition.

Major human sources: Coal burning in power plants (88%) and industrial processes(10%).

Health effects: Breathing problems for healthy people; restriction of airways in people with asthma; chronic exposure can cause a permanent condition similar to bronchitis. According to the WHO, at least 625 million people are exposed to unsafe levels of sulfur dioxide from fossil fuel burning.

Environmental effects: Reduces visibility; acid deposition of H2SO4 can damage trees, soils, and aquatic life in lakes.

Property damage: SO2 and H2SO4 can corrode metals and eat away stone on buildings, statues, and monuments; SO2 can damage paint, paper, and leather.

•EPA Standard: 0.3 ppm (annual mean)


SUSPENDED PARTICULATE MATTER (SPM)

Description: Variety of particles and droplets (aerosols) small and light enough to remain suspended in atmosphere for short periods (large particles) to long periods(small particles; Figure 20-6, p. 441); cause smoke, dust, and haze.

Major human sources: Burning coal in power and industrial plants (40%), burning diesel and other fuels in vehicles (17%), agriculture (plowing, burning off fields), unpaved roads, construction.

Health effects: Nose and throat irritation, lung damage, and bronchitis; aggravates bronchitis and asthma; shortens life; toxic particulates (such as lead, cadmium, PCBs, and dioxins) can cause mutations, reproductive problems, cancer.

Environmental effects: Reduces visibility; acid deposition of H2SO4 droplets candamage trees, soils, and aquatic life in lakes.

Property damage: Corrodes metal; soils and discolors buildings, clothes, fabrics, and paints.

EPA Standard: 50 ug/m3 (annual mean)


OZONE (O3)

Description: Highly reactive, irritating gas with an unpleasant odor that forms in the troposphere as a major component of photochemical smog (Figures 20-3 and 20-5).

Major human sources: Chemical reaction with volatile organic compounds (VOCs, emitted mostly by cars and industries) and nitrogen oxides to form photochemical smog (Figure 20-5).

Health effects: Breathing problems; coughing; eye, nose, and throat irritation; aggravates chronic diseases such as asthma, bronchitis, emphysema, and heart disease; reduces resistance to colds and pneumonia; may speed up lung tissue aging.

Environmental effects: Ozone can damage plants and trees; smog can reduce visibility.

Property damage: Damages rubber, fabrics, and paints.


LEAD

Description: Solid toxic metal and its compounds, emitted into the atmosphere as particulate matter.

Major human sources: Paint old houses), smelters (metal refineries), lead manufacture, storage batteries, leaded gasoline (being phased out in developed countries).

Health effects: Accumulates in the body; brain and other nervous system damage and mental retardation (especially in children); digestive and other health problems; some lead-containing chemicals cause cancer in test animals.

Environmental effects: Can harm wildlife.

•EPA Standard: 1.5 ug/m3

VOCs (Volatile Organic Compounds)VOCs (Volatile Organic Compounds)• Properties: organic compounds (hydrocarbons) that evaporate easily,

usually aromatic

• Effects: eye and respiratory irritants; carcinogenic; liver, CNS, or kidney damage; damages plants; lowered visibility due to brown haze; global warming

• Sources: vehicles (largest source), evaporation of solvents or fossil fuels, aerosols, paint thinners, dry cleaning

• Class: HAPs (Hazardous Air Pollutants) – Methane

– Benzene

– Chlorofluorocarbons (CFCs), etc.

• Concentrations indoors up to 1000x outdoors

• 600 million tons of CFCs

Other Air PollutantsOther Air Pollutants• Carbon dioxide Carbon dioxide

• CChlorohloroFFluoroluoroCCarbonsarbons

• FormaldehydeFormaldehyde

• BenzeneBenzene

• AsbestosAsbestos

• ManganeseManganese

• DioxinsDioxins

• CadmiumCadmium

• Others not yet fully characterizedOthers not yet fully characterized

Carbon dioxide Should it be classified as an Air Pollutant

Carbon dioxide Should it be classified as an Air Pollutant

• Most scientist would add it to the gang of six criteria air pollutants

• EPA, under pressure from most U.S. oil and coal companies, says its not

• April 2007 Supreme Court ruled that the EPA has the authority under the Clean Air Act to regulate global warming emissions

CO2 should be considered a pollutantCO2 should be considered a pollutant1. In high enough concentrations any chemical in the air can

be a pollutant.

2. We have been increasing the concentrations of CO2 in the troposphere by burning fossil fuels and clearing carbon dioxide –absorbing trees faster than they are growing back in many areas.

3. The troposphere is warming and there is considerable evidence that the additional CO2 added to the troposphere by human activities plays a role in this change.

4. Global warming can change how much precipitation falls, affects where we can grow food, and flood some areas of the world. Thus higher levels of CO2 can cause harm to some people, economies, and ecosystem.

MercuryMercury• Naturally released by volcanoes, weathering

of rocks, and evaporation of sea water. • Arises anthropogenically from coal

combustion, incineration, and smelting. • The acute effects of mercury toxicity are

difficultly walking, loss of coordination, difficulty swallowing, and tremors.

• Chronic effects include hallucinations, psychosis, and irreversible brain damage.

• Fetal exposure results in mental retardation, attention disorders, seizures, and blindness.

...when polluted air is stagnant (weather conditions, geographic location)Photochemical Smog is a mixture of air pollutants formed by the reaction of nitrogen oxides and volatile organic hydrocarbon compounds under the influence of light

Los Angeles, CA

Smog FormsSmog Forms

Photochemical SmogPhotochemical Smog

Primary Pollutants

NO2 + Hydrocarbons

Auto Emissions

UV radiation

H2O + O2


HNO3 O3

nitric acid ozone

Photochemical Smog

How can trees Contribute to Photochemical Smog? How can trees Contribute to Photochemical Smog?

• Trees certainly have environmental benefits– Emit oxygen, absorb CO2, provide shade, and help

absorb and remove various pollutants from the air.

• Some trees (some oak species, sweet gums, Poplars, and Kudzu) in and around urban areas play a large role in smog formation– They emit VOCs (like isoprene) that are ingredients in

the development of photochemical smog. – Plants in urban areas should be trees that emit low

levels of VOCs.

Formation & IntensityFormation & Intensity

FactorsFactors

• Local climate (inversions, air pressure, temperature, humidity)Local climate (inversions, air pressure, temperature, humidity)

• Topography (hills and mountains)Topography (hills and mountains)

• Population densityPopulation density

• Amount of industryAmount of industry

• Fuels used by population and industry for heating, manufacturing, Fuels used by population and industry for heating, manufacturing, transportation, powertransportation, power

• Weather: rain, snow,windWeather: rain, snow,wind

• Buildings (slow wind speed)Buildings (slow wind speed)

• Mass transit usedMass transit used

• Economics Economics

Pollutants

warmair

cool air

• surface heated by sun• warm air rises (incl. pollutants)• cools off, mixes with air of equal density & disperses

cool air

warm air (inversion layer)

• surface cools rapidly (night)• a layer of warm air overlays surface• polluted surface air rises but cannot disperse remains trapped

Thermal InversionThermal Inversion

Solarradiation

Ultraviolet radiation

NONitric oxide

P h o t o c h e m i c a l S m o g

H2OWater

NO2

Nitrogendioxide

Hydrocarbons

O2

Molecularoxygen

HNO3

Nitric acid

PANsPeroxyacyl

nitrates

Aldehydes(e.g., formaldehyde)

O3

Ozone

OAtomicoxygen

Photochemical Smog

Industrial SmogIndustrial Smog

Gray-air smog- the tiny suspended particles such as salts and carbon (soot) give the resulting industrial smog a gray color.

Gray-air smog- the tiny suspended particles such as salts and carbon (soot) give the resulting industrial smog a gray color.

Industrial smog- mixture of SO2, droplets of sulfuric acid, and a variety of suspended solid particles emitted by burning coal

Industrial smog- mixture of SO2, droplets of sulfuric acid, and a variety of suspended solid particles emitted by burning coal

Acid DepositionAcid Deposition

Measuring Acid RainMeasuring Acid Rain• Acid rain is measured using a "pH" scale.

– The lower a substance's pH, the more acidic it is.

• Pure water has a pH of 7.0.

– Normal rain is slightly acidic and has a pH of about 5.6

• Any rainfall has a pH value less than 5.6 is defined as acid rain

• As of the year 2000, the most acidic rain falling in the US has a pH of about 4.3.

Two Forms…Two Forms…

• Wet

Refers to acid rain, fog, sleet, cloud vapor and snow.

• Dry

Refers to acidic gases and particles.

CompoundsCompounds

Two main contributors to acid deposition:

• Sulfur Dioxide (SO2)

• Nitrogen Oxides (NOx)

* 66% of all sulfur dioxides and 25% of all nitrogen oxides comes from electric power generation that produces energy by burning fossil fuels.

When gas pollutants e.g. carbon dioxide, sulfur dioxide, nitrogen

dioxide dissolve in rain water, various acids are formed.

CO2 + H2O H2CO3 (carbonic acid)SO2 + H2O H2SO3 (sulfurous acid)NO2 + H2O HNO2 (nitrous acid) +

HNO3 (nitric acid)

Causes of Acid RainCauses of Acid Rain

• Sulfur dioxide (SO2) and nitrogen oxides

(NOx) are the primary causes of acid rain.

• In the US, About 2/3 of all SO2

and 1/4 of all NOx comes from electric power

generation that relies on burning fossil fuels like coal.

Acidic PrecipitationAcidic Precipitation

Fossil fuelsPower plants

Industrial emissionsAuto emissions

Primary PollutantsSO2

NO2


H2SO4 HNO2

sulfuric acid nitric acid

soilsleaching of minerals

vegetationdirect toxicity

indirect health effects

water

sedimentsleaching aluminum

acidic precipitation

Emission

Aciddeposition

SO2

H2O2

PANs

NOX

O3

Others

Direct damageto leaves and bark

Reducedphotosynthesisand growth

IncreasedSusceptibilityto drought,extreme cold,insects, mosses,and diseaseorganisms

Soil acidification

Leaching ofSoil nutrients

AcidRelease oftoxicmetal icons

Rootdamage

Reduced nutrientand water uptake

Tree death

Groundwater

Wind

Transformation tosulfuric acid (H2SO4)and nitric acid (HNO3)

Nitric oxide (NO)

Acid fog

Ocean

Sulfur dioxide (SO2)and NO

Windborne ammonia gasand particles of cultivated soilpartially neutralize acids and

form dry sulfate and nitrate salts

Dry aciddeposition

(sulfur dioxidegas and particles

of sulfate andnitrate salts)

Farm

Lakes indeep soil

high in limestoneare buffered

Lakes in shallowsoil low inlimestonebecomeacidic

Wet acid deposition(droplets of H2SO4 andHNO3 dissolved in rain

and snow)

AcidicAcidicPrecipitationPrecipitation

Fig. 17.10, p. 428BIOL 349

Atmosphere

“Wet” Acid Rain“Wet” Acid Rain

• Acidic water flows over and through the ground, it affects a variety of plants and animals.

“Dry” Acid Rain“Dry” Acid Rain• Dry deposition refers to acidic gases

and particles.

• About half of the acidity in theatmosphere falls back to earth through dry deposition.

• The wind blows these acidic particles and gases onto buildings, cars, homes, and trees.

http://svr1-pek.unep.net/soechina/images/acid.jpg

http://svr1-pek.unep.net/soechina/images/acid.jpg

Increased AcidityIncreased Acidity

• Dry deposited gases and particles can also be washed from trees and other surfaces by rainstorms.

• The runoff water adds those acids to the acid rain, making the combination more acidic than the falling rain alone.

Effects of Acid RainEffects of Acid Rain• Has a variety of effects, including damage to forests

and soils, fish and other living things, materials, and human health.

• Also reduces how far and how clearly we can see through the air, an effect called visibility reduction.

• Effects of acid rain are most clearly seen in the aquatic environments

• Most lakes and streams have a pH between 6 and 8

http://cica.indiana.edu/projects/Biology/movies.html

http://cica.indiana.edu/projects/Biology/movies.html

Buffering CapacityBuffering Capacity• Acid rain primarily affects sensitive bodies

of water, which are located in watersheds whose soils have a limited “buffering capacity”

• Lakes and streams become acidic when the water itself and its surrounding soil cannot buffer the acid rain enough to neutralize it.

• In areas where buffering capacity is low, acid rain also releases aluminum from soils into lakes and streams; aluminum is highly toxic to many species of aquatic organisms.

http://home.earthlink.net/~photofish/fish_photos/sw10_thumb.jpg

http://home.earthlink.net/~photofish/fish_photos/sw10_thumb.jpg

Effects on WildlifeEffects on Wildlife• Generally, the young of most species are

more sensitive to environmental conditions than adults.

• At pH 5, most fish eggs cannot hatch.

• At lower pH levels, some adult fish die.

• Some acid lakes have no fish.

Effects on WildlifeEffects on Wildlife• Both low pH and increased aluminum

levels are directly toxic to fish.

• In addition, low pH and increased aluminum levels cause chronic stress that may not kill individual fish, but leads to lower body weight and smaller size and makes fish less able to compete for food and habitat.

Acid Rain and ForestsAcid Rain and Forests

• Acid rain does not usually kill trees directly.

• Instead, it is more likely to weaken trees by damaging their leaves, limiting the nutrients available to them, or exposing them to toxic substances slowly released from the soil.

GermanyGermanyMongoliaMongolia

Effects of Acid Rain

Effects of Acid Rain

Great Smoky Mountains, NC

NutrientsNutrients• Acidic water dissolves the nutrients and

helpful minerals in the soil and then washes them away before trees and other plants can use them to grow.

• Acid rain also causes the release of substances that are toxic to trees and plants, such as aluminum, into the soil.

Potential problem areasbecause of sensitive soils

Potential problem areas because of air pollution: emissions leading to acid deposition

Current problem areas(including lakes and rivers)

Acid deposition Acid deposition

Reduce air pollution by improving energy efficiency

Reduce coal use

Increase natural gas use

Increase use of renewable resources

Burn low-sulfur coal

Remove SO2 particulates, and Nox from smokestack gases

Remove Nox from motor vehicular exhaust

Tax emissions of SO2

Add lime to neutralizeacidified lakes

Add phosphatefertilizer to neutralizeacidified lakes

Solutions

Acid Deposition

Prevention Cleanup

Indoor Air PollutionIndoor Air Pollution

ExposureExposure

• Time spent in various environments in US and less-developed countries

House of Commons Select Committee Enquiry on Indoor Air Pollution (1991)

• “[There is] evidence that 3 million people have asthma in the UK… and this is increasing by 5% per annum.”

• “Overall there appears to be a worryingly large number of health problems which could be connected with indoor pollution and which affect very large numbers of the population.”

• [The Committee recommends that the Government] “develop guidelines and codes of practice for indoor air quality in buildings which specifically identify exposure limits for an extended list of pollutants…”

Sources of Indoor Air Pollutants• Building materials

• Furniture

• Furnishings and fabrics

• Glues

• Cleaning products

• Other consumer products

• Combustion appliances (cookers and heaters)

• Open fires

• Tobacco smoking

• Cooking

• House dust mites, bacteria and moulds

• Outdoor air

Important Indoor Air pollutants• Nitrogen dioxide• Carbon monoxide• Formaldehyde• Volatile Organic Compounds (VOCs)• House dust mites (and other allergens, e.g. from

pets)• Environmental tobacco smoke• Fine particles• Chlorinated organic compounds (e.g. pesticides) • Asbestos and man-made mineral fibres • Radon

Health Effects

Nitrogen dioxide

• Respiratory irritant, headaches

• Elevated risk of respiratory illness in children, perhaps resulting from increased susceptibility to respiratory infection; inconsistent evidence for effects in adults

• Concentrations in kitchens can readily exceed WHO and EPA standards

Health Effects

Carbon monoxide• An asphyxiant and toxicant

• Hazard of acute intoxication, mostly from malfunctioning fuel-burning appliances and inadequate or blocked flues

• Possibility of chronic effects of long-term exposure to non- lethal concentrations, particularly amongst susceptible groups

• Can be problem for houses w/ wood-burning stoves

• Source: wood-burning stoves, fireplace, tobacco smoke, motor vehicles, kerosene, natural gas, fuel oil appliances

• Method of Prevention/ cleanup: Improved ventilation, maintenance of appliances, alternative heating method

Health EffectsFormaldehyde• Sensory and respiratory irritant and sensitizer

• Possible increased risk of asthma and chronic bronchitis in children at higher exposure levels

• Individual differences in sensory and other transient responses

• Caution over rising indoor concentrations

• Can be a problem w/ newer building

• Source: Furniture stuffing, paneling, fiberboard, foam insulation, ceiling tile, new furniture, plywood, carpeting

• Method of Prevention or cleanup: Improved ventilation, alternative building materials,

Health EffectsVolatile Organic Compounds (VOCs)• Occur in complex and variable mixtures

• Main health effects relate to comfort and well-being, but benzene (and other VOCs) are carcinogenic

• Concern about possible role of VOCs in the aetiology of multiple chemical sensitivity; also implicated in sick building syndrome

• Can be a problem w/ new buildings

• Source: Tobacco combustion, burned food products, paints, solvents, cleaning products

• Method of Cleanup/Prevention: alternative products, air filtering system

Health Effects

House dust mites• House dust mites produce Der p1 allergen, a potent sensitizer

• Good evidence of increased risk of sensitization with increasing allergen exposure, but this does not necessarily lead to asthma

• Small reductions in exposure will not necessarily lead to reduced incidence and/or symptoms

• Indoor humidity is important

Health Effects

Fungi and bacteria• Dampness and mould-growth linked to self-reported

respiratory conditions, but little convincing evidence for association between measured airborne fungi and respiratory disease

• Insufficient data to relate exposure to (non-pathogenic) bacteria to health effects in the indoor environment

• Source: Air-handling systems, damp building material, and furnishings

• Prevention/cleanup: Increase ventilation, humidity control,

Health Effects

Environmental tobacco smoke (ETS)• Sudden infant death syndrome • Lower respiratory tract illness • Middle ear disease • Asthma • Leading cause of lung cancer• Second hand smoke is the third leading cause of lung

cancer

12 million children exposed to secondhand 12 million children exposed to secondhand smoke in homessmoke in homes

Health Effects

Fine particles• Consistent evidence that exposure to small

airborne particles (e.g. PM10) in ambient air can impact on human health; mechanisms uncertain

• Chronic Obstructive Pulmonary Disease and Cardiovascular Disease patients and asthmatics probably at extra risk

• Relative importance of indoor sources is unknown• Sources: Tobacco combustion, wood burning,

dust, agriculture, unpaved roads, pet dander

Health effectsHealth effects

• is a naturally occurring fiber used because of its fire-retardant nature.

• It was used in insulation, ceiling tiles, roofing, and brake lining in automobiles.

• 1997 is was phased out because it was realized that it induced the chronic lung disease asbestosis, lung cancer, and mesothellioma ( a rare, fatal cancer)

• Removing it was more dangerous than leaving it in placed. • Can be a problem w/ “older houses”• Source: Insulation, floor and ceiling tile, spray on fire

retardant, roof shingles

Asbestos

Health EffectsHealth EffectsRadon• Can cause lung cancer• Estimated that 7,000 to 30,000 Americans die each year

from radon-induced lung cancer• Only smoking causes more lung cancer deaths• Smokers more at risk than non-smokers• Sources: radioactive soil, rock foundations and building

material, Uranium deposits. Radioactive well water.• Cleanup/ Prevention: Improved ventilation, sealing

cracks

RadonRadon

Radioactive radon-222 Radioactive radon-222

Lung cancer threat Lung cancer threat

Occurs in certain areas based on geology

Occurs in certain areas based on geology

Associated with uranium and organic material in rock

Associated with uranium and organic material in rock Fig. 20-14

p. 451

Radon Risk: Non-SmokerRadon Risk: Non-SmokerRadon Level

(pCI/L)

If 1000 people who did not smoke were exposed to this level over a lifetime..

About X would get lung cancer

This risk of cancer from radon exposure compares to

…What to do:

20 8 Being killed in a violent crime

Fix your home

10 4 Fix your home

8 3 10x risk of dying in a plane crash

Fix your home

4 2 Risk of drowning Fix your home

2 <1 Risk of dying in a home fire Fix your home

1.3 <1 Average indoor radon level Fix your home

.4 <1 Average indoor radon level Fix your home

If you are a former smoker, your risk may be higherIf you are a former smoker, your risk may be higher

Radon Risk: SmokerRadon Risk: SmokerRadon Level

(pCI/L)

If 1000 people who smoke were exposed to this level over a lifetime.. About X would

get lung cancer

This risk of cancer from radon exposure compares to

…

What to do:

Stop smoking and …

20 135 100x risk of drowning Fix your home

10 71 100x risk of dying in a home fire

Fix your home

8 57 Fix your home

4 29 100x risk of dying in a plane crash

Fix your home

2 15 2x the risk of dying in a car crash

Fix your home

1.3 9 Average indoor radon level Fix your home

.4 3 Average indoor radon level Fix your home

If you are a former smoker, your risk may be lowerIf you are a former smoker, your risk may be lower

RadonRadon

• 55% of our exposure to radiation comes from radon

• colorless, tasteless, odorless gas

• formed from the decay of uranium

• found in nearly all soils

• levels vary

(From: http://www.epa.gov/iaq/radon/zonemap.html)

Zone pCi/L 1 >4 2 2 - 4 3 <2

Radon: How it Enters BuildingsRadon: How it Enters Buildings

• Cracks in solid floors• Construction joints• Cracks in walls• Gaps in suspended floors• Gaps around service pipes• Cavities inside walls• The water supply

http://www.epa.gov/iaq/radon/pubs/citguide.html#howdoes

Radon: Reducing the RisksRadon: Reducing the Risks• Sealing cracks in floors and walls

• Simple systems using pipes and fans

• More information:

http://www.epa.gov/iaq/radon/pubs/consguid.html#reductiontech

Sick Building Syndrome (SBS)Sick Building Syndrome (SBS)

vsvs

Building Related Illness (BRI)Building Related Illness (BRI)

Sick Building Syndrome

• A persistent set of symptoms in > 20% population

• Causes(s) not known or recognizable• Complaints/Symptoms relieved after

exiting building • Linked to inadequate ventilation, new buildings

that contain chemicals such as formaldehyde from building products, or biological contaminants like mold or pollen.

Complaints/Symptoms

• Headaches• Fatigue• Reduced Mentation• Irritability • Eye, nose or throat

irritation

• Dry Skin• Nasal Congestion• Difficulty Breathing• Nose Bleeds• Nausea

Building Related Illness

• Clinically Recognized Disease

• Exposure to indoor air pollutants

• Recognizable Causes

Clinically Recognized Diseases

– Pontiac Fever – Legionella spp.– Legionnaire's Disease– Hypersensitivity Pneumonitis– Humidifier Fever– Asthma– Allergy– Respiratory Disease

• Chronic Obstructive Pulmonary Disease

Ventilation

Movement of Air Into / Out of HomesMovement of Air Into / Out of Homes

• Amount of air available to dilute pollutants– important indicator of the likely contaminant

concentration

• Indoor air can mix with outside air by three mechanisms– infiltration– natural ventilation– forced ventilation

Movement of Air Into / Out of HomesMovement of Air Into / Out of Homes• Infiltration

– natural air exchange that occurs between a building and its environment when the doors and windows are closed

– leakage through holes or openings in the building envelope

– pressure induced• due to pressure differentials inside and outside of the building

• especially important with cracks and other openings in wall


• Infiltration– Temperature induced (stack effect)

• driven by air movement through holes in floors, ceilings

• in winter, warm air in a building wants to rise, exits through cracks in ceiling and draws in

Movement of Air Into / Out of HomesMovement of Air Into / Out of Homes• Natural ventilation

– air exchange that occurs when windows or doors are opened to increase air circulation

• Forced ventilation– mechanical air handling systems used to induce air exchange

using fans and blowers

• Trade-offs– cut infiltration to decrease heating and cooling costs vs. indoor

air quality problems


• Infiltration rates– Influenced by

• how fast wind is blowing, pressure differentials• temperature differential between inside and outside of

house• location of leaks in building envelope

Solutions: Preventing and Reducing Air PollutionSolutions: Preventing and Reducing Air Pollution

Clean Air ActClean Air Act

National Ambient Air Quality Standards (NAAQS)

National Ambient Air Quality Standards (NAAQS)

Primary and secondary standardsPrimary and secondary standards

Emissions tradingEmissions trading

TheCleanAirAct

Congress found:

• Most people now live in urban areas

• Growth results in air pollution

• Air pollution endangers living things

It decided:

• Prevention and control at the source was appropriate

• Such efforts are the responsibility of states and local authorities

• Federal funds and leadership are essential for the development of effective programs


• Originally signed 1963– States controlled standards

• 1970 – Uniform Standards by Federal Govt.– Criteria Pollutants

• Primary – Human health risk• Secondary – Protect materials, crops,

climate, visibility, personal comfort


• 1990 version – Acid rain, urban smog, toxic air pollutants, ozone

depletion, marketing pollution rights, VOC’s

• 1997 version– Reduced ambient ozone levels– Cost $15 billion/year -> save 15,000 lives – Reduce bronchitis cases by 60,000 per year– Reduce hospital respiratory admission 9000/year


President George W. Bush signed rules amending Clean Air Act that allowed power plants and other

industries to increase pollution significantly without adopting control measures

WASHINGTON (AP) -- A federal appeals court on Wednesday blocked new Bush administration changes to the Clean Air Act from going into effect the next day, in a challenge from state attorneys general and cities that argued they would harm the environment and public health.

Appeals court blocks Bush clean air changesWednesday, December 24, 2003 Posted: 2:10 PM EST (1910 GMT)

http://www.cnn.com/2003/LAW/12/24/bush.clean.air.ap/index.html

Clean Air Act http://www.epa.gov/air/oaq_caa.html Clean Air Act http://www.epa.gov/air/oaq_caa.html

• Title I - Air Pollution Prevention and Control– Part A - Air Quality and Emission Limitations

– Part B - Ozone Protection (replaced by Title VI)

– Part C - Prevention of Significant Deterioration of Air Quality

– Part D - Plan Requirements for Nonattainment Areas

• Title II - Emission Standards for Moving Sources– Part A - Motor Vehicle Emission and Fuel Standards

– Part B - Aircraft Emission Standards

– Part C - Clean Fuel Vehicles

• Title III - General

• Title IV - Acid Deposition Control

• Title V - Permits

• Title VI - Stratospheric Ozone Protection

Emission ReductionEmission Reduction

Solutions

Stationery Source Air Pollution

Prevention Dispersion or Cleanup

Burn low-sulfurcoal

Remove sulfurfrom coal

Convert coalto a liquid orgaseous fuel

Shift to lesspolluting fuels

Disperseemissions abovethermal inversionlayer with tallsmokestacks

Removepollutants aftercombustion

Tax each unitof pollutionproduced

Prevention of Air pollution Prevention of Air pollution

• Using a higher grade of coal (anthracite)

• Washing the coal to remove excess sulfur.

• Coal may be converted into gas or oil, which removes the sulfur

Precombustion methods

Prevention of Air pollutionPrevention of Air pollution

• Fluidized bed combustion is carried out by burning the crushed coal w/ crushed limestone.

• The sulfur in the coal combines w/ the calcium to form calcium sulfate, or gypsum.

• The bottom ash then can be disposed of

Combustion method

Prevention of Air pollutionPrevention of Air pollution

• Catalytic converter to oxidize the sulfur to yield sulfur compounds.

• A lime scrubber in a smokestack may be used• In a wet scrubber, a slurry of lime mixed w/ water

is sprayed across the exiting gases. The sulfur mixes w/ the calcium, forming the calcium sulfate, which falls to the bottom of the smokestack as bottom ash.

• Most particulates are removed post combustion

Post combustion method

Electrostatic Precipitator

Dirty gas

Dust discharge

ElectrodesCleaned gas

Cleaned gas

Dirty gas

Baghouse Filter Dust discharge

Bags

Cyclone Separator

Dirty gas

Dust discharge

Cleaned gas

Dirty gas

Dirty water

Cleanwater

Wet Scrubber

Wetgas

Cleaned gas

Reducing Motor Vehicle Air PollutionReducing Motor Vehicle Air Pollution

Fig. 20-19 p. 458 Slide 32Slide 32Slide 32Slide 32Slide 32Slide 32Slide 32Slide 32Slide 32Slide 32Slide 32Slide 32Slide 32Slide 32Slide 32Slide 32Slide 32Slide 32

Solutions

Motor Vehicle Pollutions

Prevention Cleanup

Mass transit

Bicycles and walking

Less polluting engines

Less polluting fuels

Improve fuel efficiency

Get older, pollutingcars off the road

Give buyers tax write-offs for buying low-polluting, energy-efficient vehicles

Restrict driving inpolluted areas

Emission controldevices

Car exhaustInspectionstwice a year

Stricter emissionstandards

Figure 20-19Page 458

Solutions

Indoor Air Pollution

Prevention Cleanup

Cover ceiling tiles and lining of AC ducts to prevent release of mineral fibers

Ban smoking or limit it to well-ventilated areas

Set stricter formaldehyde emissions standards for carpet, furniture, and building materials

Prevent radon infiltration

Use office machines in well-ventilated areas

Use less polluting substitutes for harmful cleaning agents, paints, and other products

Use adjustable fresh air vents for work spaces

Increase intake of outside air

Change air more frequently

Circulate building’s air through rooftop greenhouses

Use exhaust hoods for stoves and appliances burning natural gas

Install efficient chimneys for wood-burning stoves

Solutions

Air Pollution

Prevention Cleanup

Improve energy efficiencyto reduce fossil fuel use

Rely more on lower-polluting natural gas

Rely more on renewable energy (especially solar cells, wind, and solar-produced hydrogen)

Transfer technologies for latest energy efficiency, renewable energy, and pollution prevention to developing countries.

Reduce poverty

Distribute cheap and efficient cookstoves to poor families in developing countries

Reduce or ban indoor smoking

Develop simple and cheap test for indoor pollutants such as particulates, radon, and formaldehyde

What Can You Do?

Indoor Air Pollution

• Test for radon and formaldehyde inside your home and take corrective measures as needed.• Do not buy furniture and other products containing formaldehyde.• Remove your shoes before entering your house to reduce inputs of dust, lead, and pesticides.• Test your house or workplace for asbestos fiber levels and for any crumbling asbestos materials if it was built before 1980.• Don't live in a pre-1980 house without having its indoor air tested for asbestos and lead.• Do not store gasoline, solvents, or other volatile hazardous chemicals inside a home or attached garage.• If you smoke, do it outside or in a closed room vented to the outside.• Make sure that wood-burning stoves, fireplaces, and kerosene- and gas- burning heaters are properly installed, vented, and maintained.• Install carbon monoxide detectors in all sleeping areas.

g. tyler miller’s living in the environment 14 th edition chapter 20 air pollution

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