outdoor & indoor air pollution
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OUTDOOR & INDOOR
AIR POLLUTION
Outdoor Air Pollution
Primary PollutantsPrimary Pollutants
Secondary PollutantsSecondary Pollutants
SourcesSourcesNaturalNatural
StationaryStationary
COCO COCO22
SOSO22 NONO NONO22
Most hydrocarbonsMost hydrocarbons
Most suspendedMost suspendedparticlesparticles
SOSO33
HNOHNO33 HH22SOSO44
HH22OO22 OO33 PANsPANs
MostMost andand saltssaltsNONO33––
MobileMobile
SOSO4422 ––
Primary vs. Secondary Pollutants
• Primary- put directly into air from polluting source.
• Secondary- when primary combines with other substances in air and creates something more hazardous (acid rain, smog)
• Sun often provides energy for these rxns.
Major Sources of Primary Pollutants
Stationary 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 aerosols
Mobile Sources• Highway: cars, trucks, buses and motorcycles• Off-highway: aircraft, boats, locomotives, farm
equipment, RVs, construction machinery, and lawn mowers
Natural Sources
• Forest fires- ash, particulates, carbon dioxide• Volcanoes- ash, acid mist, hydrogen sulfide• Decaying vegetation- sulfur cmpds• Trees & bushes- Volatile Organic Cmpds (VOC’s) give
Blue Ridge Mtns. their blue hue• Pollen • Spores• Viruses• Bacteria• Dust- from storms in arid regions• Gut bacteria- methane gas
Anthropogenic Sources of Air Pollution
Criteria Air PollutantsEPA uses seven "criteria pollutants" as indicators
of air quality1. Sulfur Dioxide: SO2
2. Nitrogen Dioxide: NO2
3. Carbon monoxide: CO
4. Lead: Pb
5. Particulate Matter: PM10 (PM 2.5)
6. Volatile Organic Compounds: (VOCs)
7. Ozone: ground level O3
Sulfur Dioxide (SO2) • Properties: colorless gas with irritating odor• Effects: produces acid rain (H2SO4), breathing
difficulties, eutrophication due to sulfate formation, lichen and moss are indicators
• Sources: burning high sulfur coal or oil in power plants, smelting or metals, paper manufacture
• Class: sulfur oxides• EPA Standard: 0.3 ppm (annual mean)• 2nd largest cause of air pollution-related health
damage. (1st is smoking)• Sulfate particles reduce visibility in the U.S. as much
as 80%• Reflects sunlight so may have cooling effect
Sulfur Dioxide Emissions
See figure 18.5 on page 400
Nitrogen Dioxide (NO2)• Properties: reddish brown gas, formed as fuel
burned in car, strong oxidizing agent, forms Nitric acid (HNO3) in air
• Effects: acid rain, lung and heart problems, decreased visibility (yellow haze), suppresses plant growth
• Sources: fossil fuels combustion, power plants, forest fires, volcanoes, bacteria in soil, fertilizers
• Class: Nitrogen oxides (NOx) • EPA Standard: 0.053 ppm• Excess nitrogen is causing fertilization &
eutrophication of inland waters & seas
Mobile Source Emissions: Nitrogen Oxides
Carbon Monoxide (CO)• Properties: colorless, odorless, heavier than air,
0.0036% of atmosphere
• Effects: binds tighter to Hemoglobin (Hb) than O2, so organs do not get O2 needed, makes you sleepy, impairs mental functions and visual acuity, even at low levels
• Sources: incomplete combustion of fossil fuels 60 - 95% from auto exhaust
• Class: carbon oxides (CO2, CO)
• EPA Standard: 9 ppm • 1 billion tons enter atmosphere/year
Mobile Source Emissions – CO
Lead (Pb)• Properties: grayish metal• Effects: accumulates in tissue; affects kidneys, liver
and nervous system (children most susceptible); mental retardation; possible carcinogen; 20% of inner city kids have high levels
• Sources: particulates from fuel combustion, smelters, batteries
• Class: toxic or heavy metals• EPA Standard: 1.5 ug/m3
• 2 million tons enter atmosphere/year• Mercury- neurotoxin from coal power plants • Both mercury & lead travel on air currents and fall into
aquatic ecosystems causing bioaccumulation & biomagnification in food webs.
Suspended Particulate Matter (PM10) •Properties: particles suspended in air (<10 um)
•Effects: lung damage, mutagenic, carcinogenic, teratogenic
•Sources: burning coal or diesel, volcanoes, factories, unpaved roads, plowing, lint, pollen, spores, burning fields
•Class: SPM: dust, soot, asbestos, lead, PCBs, dioxins, pesticides
•EPA Standard: 50 ug/m3 (annual mean)• PM2.5 is worse b/c small enuf to be inhaled more deeply• Asbestos fibers & cigarette smoke are most dangerous
respirable particles b/c they are carcinogenic
Mobile Source Emissions: Fine Particulate Matter (PM2.5)
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, wetlands, rice paddies, bacteria, plants (Figure 18.8)
• Class: HAPs (Hazardous Air Pollutants- cause cancer, birth defects, mutation, neutroxins) – Methane– Benzene– Chlorofluorocarbons (CFCs), etc.
• Concentrations indoors up to 1000x outdoors• 600 million tons of CFCs
Ozone (O3)• Properties: colorless, unpleasant odor, major part
of photochemical smog• Effects: lung irritant, damages plants, rubber,
fabric, eyes • Sources: Created by sunlight acting on NOx and
VOC , photocopiers, cars, industry, gas vapors, chemical solvents, incomplete fuel combustion products
• Class: photochemical oxidants• Good ozone vs. bad ozone- good is in stratosphere
and bad is at ground level (from cars)• Figure 18.10 shows secondary production of urban
smog by photochemical rxns in atmosphere
Other Air Pollutants• Carbon dioxide- natural source from Carbon dioxide- natural source from
photosynthesis & respiration; human caused photosynthesis & respiration; human caused from fossil fuels & deforestationfrom fossil fuels & deforestation
• CChlorohloroFFluoroluoroCCarbons (CFC’s)- from arbons (CFC’s)- from refrigerants, aerosols, Styrofoamrefrigerants, aerosols, Styrofoam
• Formaldehyde- building materials & Formaldehyde- building materials & household productshousehold products
• Benzene- paintBenzene- paint• Asbestos- car brakes, building materialsAsbestos- car brakes, building materials• Dioxins- pesticidesDioxins- pesticides• Cadmium- smelting, batteries, plastics Cadmium- smelting, batteries, plastics
industryindustry
Formation & Intensity of Pollutant is influenced by…
• 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, Fuels used by population and industry for heating,
manufacturing, transportation, powermanufacturing, transportation, power• Weather: rain, snow,windWeather: rain, snow,wind• Buildings (slow wind speed)Buildings (slow wind speed)• Mass transit usedMass transit used
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 Inversion- occur in valleys
-pollutant effects are intensified when air cannot move upward due to cold upper air layer
...when polluted air is stagnant (weather conditions, geographic location)
Los Angeles, CA
Smog Forms
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
Urban Heat Islands
• Cities are generally 3-5ºC warmer than rural areas
• Caused by:– Lack of vegetation to absorb heat– Dark buildings & roads trap heat– Buildings create windbreaks
• Dust Dome- trapping of dirt & particulates over city
INDOOR AIR POLLUTION
What are some sources of indoor air pollution?
1. Cigarette smoke– Deadliest indoor air
pollutant– Contain formaldehyde,
carbon monoxide– Causes lung cancer,
emphysema– Second hand smoke may
be worse due to particulates that come from tip.
What are some sources of indoor air pollution?
2. Mold– Moisture in vents,
carpets– Allergy symptoms,
breathing problems, headache, fatigue
What are some sources of indoor air pollution?
3. Carbon monoxide– Malfunctioning
furnace, gas appliances, cars
– Blood cannot carry oxygen
– Feel sleepy, nausea, dizzy, cause death.
What are some sources of indoor air pollution?
4. Radon– Colorless, odorless,
radioactive gas– Comes from soil under
basements– Long term exposure can
cause lung cancer– Fix cracks in floor or walls
to prevent influx of radon– Install ventilation fan in
basement to blow radon out.
Zone 1 (purple) high levels of radon
Zone 3 (yellow) low levels of radon
What are some sources of indoor air pollution?
5. Asbestos– Roofing, flooring,
insulation, brakes– OK… unless
disturbed or deteriorates
– Can cause asbestosis (scarring of lungs) and mesothelioma (type of lung cancer)
Plaque build up (scarring) in lung w/asbestosis
What are some sources of indoor air pollution?
6. Lead– Old homes, toys,
lead crystal dishes– Causes behavior &
learning problems, slow growth, hearing problems, headaches
What are some sources of indoor air pollution?
7. Formaldehyde– Pressed wood,
paneling, particle board, glue, deodorizers
– Respiratory irritation, fatigue, skin rash, known to cause cancer
What are some sources of indoor air pollution?
8. VOC’s– Paradichlorobenzene-
mothballs, insecticides– PERC- dry cleaned
clothes– Benzene- paints,
cigarettes– Causes respiratory
problems, headaches, loss of coordination, nausea, organ damage, cancer
Effects of Air Pollution on…
1. Human Health
2. Plant Health
3. Acid Deposition
1. Human Health
• Depends on intensity & duration of exposure, age & prior health status
• At-risk groups: young, old, or already suffering from respiratory/cardiovascular disease. Also, more active & outside vs. sedentary inside lifestyle
• Most susceptible- LDC use smoky fires for cooking & heating
Exposure• Time spent in various environments in US and
less-developed countries
How is it introduced to body?
• Inhalation
• Absorption thru skin
• Contamination of food & water
How does air pollution affect people?
• Chronic bronchitis- coughing, trouble breathing
• Asthma- not caused by air pollution, but aggravated by it.
• Emphysema- lungs lose elasticity, hard to breathe
• Lung Cancer- caused by cigarettes, car exhaust, particulates, asbestos, arsenic, radon
How does air pollution affect people? Sick building syndrome-
– Buildings closed up to save energy- no circulation
– Effects of fumes intensified
– Symptoms: headache, eye or throat irritation, cough, itchy skin, dizziness, nausea, fatigue
– Feel better when you get fresh air outside.
– ≥20% of workers must be afflicted to be classified as SBS
2. Plant Health• Two Methods of Damage
– Directly toxic• Irritate cell membranes• First few days- discoloration due to
chlorosis (bleaching) of leaf• Later- necrotic (dead) lesions develop
leading to death– Disruption of plant hormones
• Ethylene from fossil fuels, chemical plants is a major culprit
• Synergistic effects (when combined two are worse than each individually) unpredictable
– White pine seedlings exposed to low levels of O3 & SO2 individually are fine. When combined cause death
– In alfalfa, O3 and SO2 together are less harmful than individually.
• Air pollutant effects on plants are sometimes confused with insect damage or other diseases.
Necrotic lesions on lower surface of potato leaves
Chlorosis and necrosis of white pine needles
Necrosis of watermelon leaf
3. Acid Deposition
Measuring Acid Rain• Normal rain is slightly
acidic and has a pH of about 5.0-5.6
• Any rainfall with a pH value less than 5.0 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…
• Wet
Refers to acid rain, fog, sleet, cloud vapor and snow.
• Dry
Refers to acidic gases and particles.
Increased 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.
Compounds
Two main contributers to acid deposition:• Sulfur Dioxide (SO2)• Nitrogen Oxides (NOx)
– NO- nitric oxide (or nitrogen monoxide)– NO2- nitrogen dioxide– N2O- nitrous oxide
• 66% of all sulfur dioxides and 25% of all nitrogen oxides comes from coal or oil electric power plants. Most nitrogen oxides come from cars
When gas pollutants e.g. sulfur dioxide, nitrogen dioxide dissolve
in rain water, various acids are formed.
CO2 + H2O H2CO3 (carbonic acid)SO2 + H2O H2SO3 (sulfuric acid)NO2 + H2O HNO2 (nitrous acid) +
HNO3 (nitric acid)
Acidic 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
sedimentsleaching aluminum
acidic precipitation
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
Effects of Acid Rain• The strength of the effects depend on many
factors– How acidic the water is
– The types of fish, trees, and other living things that rely on the water
– The chemistry and buffering capacity of the soils involved
• limestone & basalt have high buffering capacity• have high ANC (Acid Neutralizing Capacity)
Effects 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 Capacity• Acid rain primarily affects sensitive
bodies of water, which are located in watersheds whose soils have a limited “buffering capacity” (places that have granite bedrock or soil for example)
• 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.– Can attach to fish gills causing suffocation– Can release from soil particles & enter solutions taken up by
plants causing death
http://home.earthlink.net/~photofish/fish_photos/sw10_thumb.jpg
Effects on Wildlife
• Some birds have left areas- no fish, forests destroyed- less nesting space
• 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.
• Both low pH and increased aluminum levels are directly toxic to fish. – Can also stress fish resulting in low
body weight, small size, less able to compete for food, habitats, reduced reproduction, increased susceptibility to disease
Salmon populations have decreased in Norway since 1950 due to acid rain. Red areas show where populations have declined.
Loons no longer nesting in Adirondack Mtn lakes- too acidic for fish which they eat
Acid Rain and Forests
• Acid rain does not usually kill trees directly.
• Instead, it is more likely to – weaken trees by damaging their leaves– limit the nutrients available to them– expose them to toxic substances slowly
released from the soil.
Acid Rain & Forests
• Trees at higher elevations can be more effected because of increased exposure to acid fog or acid cloud vapor
• As water evaporates from leaf, acid becomes more concentrated, burning the leaf tissue.
• Adirondack Mtns
Effects of Acid Rain
Great Smoky Mountains, NC
Effects on Plant Nutrients• 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.
Effects on Property
• Many statues, monuments, etc. made from limestone (CaCO3), marble or metal
• Acid rain can dissolve rock or tarnish metal
• Expensive to restore, refurbish, maintain
• Car manufacturers now use acid-resistant paint at a cost of $5.00 per new vehicle
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