Chapter 18-19 Air Pollution There is no place on Earth that
isnt affected by air pollution
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Air pollution: presence of chemicals in the atmosphere in
concentrations high enough to harm organisms, ecosystems,
human-made materials or to alter climate Ranges from annoying to
lethal Refers to pollution in the troposphere Natural sources Dust,
wildfires, volcanic eruptions Human sources Industrialized and
urban areas fossil fuel burning
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Primary Pollutants: chemicals or substances emitted directly
into the air from natural sources and human activities Carbon
monoxide, carbon dioxide, sulfur dioxide and nitric oxides;
particulate matter; VOCs (natural sourcesterpenes, plant fragrance)
Secondary Pollutants: primary pollutants react with one another and
natural components to form harmful chemicals, often in the presence
of sunlight and water Ozone, acid deposition (sulfates and
nitrates) To determine and monitor Air Quality, the EPA actively
monitors carbon monoxide ozone lead nitrogen dioxide particulate
matter (also known as particle pollution) sulfur dioxide
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Major Air Pollutants Carbon Oxides Carbon Dioxide: from fossil
fuel burning (major pollutant); is a greenhouse gas that impacts
climate; required for photosynthesis; colorless and odorless Carbon
Monoxide: from combustion of carbon (exhaust, forest burning,
fossil fuels, tobacco smoke); Limits oxygen binding in hemoglobin
which can result in heart attack, asthma, emphysema, nausea and
death; colorless and odorless dangerous indoor air pollutant
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Nitrogen Oxides (NOx) and Nitric Acid Nitric Oxide (NO):
combustion in cars, coal burning, lightning, part of soil and water
(nitrogen cycle); colorless and odorless Nitrogen Dioxide (NO 2 ):
nitrogen monoxide reacts with oxygen (NO 2 ); reacts with water to
form nitric acid and nitrate salts (acid deposition); forms
photochemical smog (with sunlight); helps in the formation of
tropospheric ozone; stinky, reddish-brown gas Nitrous Oxide (N 2
O): greenhouse gas from fertilizers and animal wastes, also fossil
fuel burning ** all are irritants to eyes, nose and throat,
aggravate asthma and bronchitis; suppress plant growth and harm
aquatic life
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Sulfur Dioxide and Sulfuric Acid Sulfur Dioxide (SO 2 ): 1/3
comes from natural sources (sulfur cycle), the rest is
anthropogenic (coal burning, oil refining, smelting); corrosive gas
Sulfuric Acid: forms when SO 2 reacts with water in the atmosphere,
then falls as acid deposition (acid rain). **Aggravate breathing
problems (respiratory irritant), decrease plant growth,
corrosive
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Particulates Suspended particulate matter (solid particles and
liquid droplets); particles smaller than 10 micrometers are
regulated by the EPA as air pollution (not filtered by nose/throat)
Outdoor: dust, wildfires, sea salt, coal/oil burning, cars
(especially diesel), construction; road dust, rock crushing;
volcanic activity Indoor: cigarettes, burning inside (developing
countries) **Aggravate eyes, nose, and throat, damage lungs,
asthma/bronchitis, genetic mutations, and cancer (premature death)
**Reduces the amount of incoming solar radiation (weather)
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Ozone (O 3 ) Secondary pollutant that contributes to
photochemical smog Tropospheric ozone bad. Stratospheric ozone
good. Ozone thinning is the stratospherewhich increases the amount
of UV radiation that reaches us Damages living tissue Results from
release of CFCs and other Freonsfrom coolants and aerosols Montreal
ProtocolLimit these chemicals in manufactured products **Coughing
and breathing problems (asthma and emphysema), lung/heart disease,
irritant; damaging to rubber and plastic
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Volatile Organic Compounds (VOCs) Organic compounds
(hydrocarbons) that exist as gases in the atmosphere Give off
strong aroma (paint, perfume, gasoline, flatulence) Help in
formation of smog, not all hazardousbut some have the potential to
be harmful Ex. Methanegreenhouse gas from landfills, cows,
decomposition, oil and gas burning/refining Others include benzene,
industrial solvents, gas and plastics
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Mercury: found in coal and oil, released from fossil fuel
burning, can settle out into water. Seeing bioaccumulation into
food chains. Toxin for central nervous system Lead: occurs
naturally in rocks and soils, also present in fuels and paints.
Toxic to central nervous system (children), affects learning,
concentration, and intelligence
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Factors Affecting Air Pollution Increase air pollution
Buildings break up wind Hills/mountains decrease air flow High
temperature increases reactions Emissions of VOCs increase smog
formation Temperature inversions (warm air over cool) Decrease air
pollution Heavy particles settle out of air Rain/snow cleanse air
Salty sea spray washes air Winds mix air Pollutants removed by
reactions
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Acid Deposition Air pollutants mix with water in air to form
acidic precipitation (acid rain) Nitrogen and sulfur oxidesform
nitric and sulfuric acid (pH ~5) Has been occurring since the
Industrial Revolution Usually a regional problemdownwind of coal
burning facilities Pollutants are moved by winds Damages statues,
buildings; causes respiratory diseases, leach toxic metals into the
environment from rocks; harmful to aquatic ecosystems, hurts
agriculture, and weakens forests and plants Reduced by limiting
emissions of pollutants (alternative energy sources)
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Smog Industrial Unhealthy mix of sulfur dioxide and sulfuric
acid and solid particles Comes from coal burning in large
quantities Rarely a problem in developed countriesbig problem in
developing (China) Sulfur dioxide and sulfates mostly; grey smog
Photochemical Mixture of primary and secondary pollutants formed
under the influence of UV radiation brown smogmade up mostly of
ozone
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Indoor vs. Outdoor Air Pollution Indoor Air Pollution from
burning wood, charcoal in open fires or poorly designed stoves;
cigarette smoke Carbon monoxide and particulates Impacts high
poverty/poor countries Sources include: Tobacco smoke formaldehyde
Radon gas Fine particulates Pesticide residues Lead Organic
solvents Living organisms (mites, roaches) Mold and fungal
spores
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Radon Gas Colorless, odorless radioactive gas that is produced
by the radioactive decay of uranium-238 (from underground rock)
Only problematic in certain areas of the country Can seep through
cracks in the foundation and build up to harmful levels in air, or
seep into groundwater Damages lung tissue and lead to cancer
(second leading cause of lung cancer) Radon-222 decays to
Polonium-210 (harmful/carcinogen)
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Dealing with Air Pollution Clean Air Act: set aside air
pollution regulations EPA monitors pollutants and sets standards
for emissions EPA's mission is to protect human health and the
environment. To achieve this mission, EPA implements a variety of
programs under the Clean Air Act that focus on: reducing outdoor,
or ambient, concentrations of air pollutants that cause smog, haze,
acid rain, and other problems; reducing emissions of toxic air
pollutants that are known to, or are suspected of, causing cancer
or other serious health effects; and phasing out production and use
of chemicals that destroy stratospheric ozone. These pollutants
come from stationary sources (like chemical plants, gas stations,
and powerplants) and mobile sources (like cars, trucks, and
planes). Buy and sell pollution allotments Prevention in best
solution! Improve fuel efficiency standards Alternative energy
sources Educate public about pollution
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Air Quality Index National Ambient Air Quality Standards EPA
sets standards for pollutants harmful to humans or the environment
(clean air act) Primary standards protect public health Secondary
standards protect public welfare Carbon Monoxide, Lead,
Particulates, Ozone, Nitrogen Dioxide and Sulfur Dioxide
