www.aqmd.gov/pubinfo/ 97annual.html
G. Tyler Miller’s
Living in the Environment
14th Edition
Chapter 20
Air Pollution
Slide 1Slide 1Slide 1Slide 1Slide 1Slide 1Slide 1Slide 1Slide 1Slide 1Slide 1Slide 1Slide 1Slide 1Slide 1Slide 1Slide 1Slide 1
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)
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
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
Table 20-2Page 438Table 20-2Page 438Table 20-2 Major Outdoor Air Pollutants
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)
Table 20-2Page 438Table 20-2Page 438Table 20-2 Major Outdoor Air Pollutants
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)
Table 20-2Page 438Table 20-2Page 438Table 20-2 Major Outdoor Air Pollutants
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.
Table 20-2Page 438Table 20-2Page 438Table 20-2 Major Outdoor Air Pollutants
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
Secondary Pollutants
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
Secondary Pollutants
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
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
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
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
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
Movement of Air Into / Out of HomesMovement of Air Into / Out of Homes
• 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
Movement of Air Into / Out of HomesMovement of Air Into / Out of Homes
• 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
Clean Air ActClean Air Act
• 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
Clean Air ActClean Air Act
• 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
Clean Air ActClean Air Act
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.