Aim15: Outdoor Air Pollution
Aim #15: Outdoor Air Pollution
1. Air pollution
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Aim15: Outdoor Air Pollution
A. Primary Pollutants
B. Secondary Pollutants
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Aim15: Outdoor Air Pollution
2. Common Air Pollutants
A. Carbon Based
Carbon monoxide (CO) is a highly toxic gas that forms during the incomplete combustion of carbon­containing materials.
93% of carbon dioxide (CO2) in the troposphere occurs as a result of the carbon cycle.
7% of CO2 in the troposphere occurs as a result of human activities (mostly burning fossil fuels).
It is not regulated as a pollutant under the U.S. Clean Air Act.
i. Carbon Cycle
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Aim15: Outdoor Air Pollution
2. Common Air Pollutants
B. Nitrogen Based
Nitrogen oxide (NO) forms when nitrogen and oxygen gas in air react at the high­combustion temperatures in automobile engines and coal­burning plants. NO can also form from lightening and certain soil bacteria.
NO reacts with air to form NO2.
NO2 reacts with water vapor in the air to form nitric acid (HNO3) and nitrate salts (NO3­) which are components of acid deposition.
i. Nitrogen Cycle
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Aim15: Outdoor Air Pollution
2. Common Air Pollutants
C. Sulfur Based
About one­third of sulfur dioxide, SO2 in the troposphere occurs naturally through the sulfur cycle.
Two­thirds come from human sources, mostly combustion (S+ O2 = SO2) of sulfur­containing coal and from oil refining and smelting of sulfide ores. SO2 in the atmosphere can be converted to sulfuric acid (H2SO4) and sulfate salts (SO42­ ) that return to earth as a component of acid deposition.
i. Sulfur Cycle
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Aim15: Outdoor Air Pollution
3. Other Air Pollutants
A. Suspended particulate matter
SPM
Consists of a variety of solid particles and liquid droplets small and light enough to remain suspended in the air.
The most harmful forms of SPM are fine particles (PM­10, with an average diameter < 10 micrometers) and ultrafine particles (PM­2.5).
3. Other Air Pollutants
B. Ozone
Is a highly reactive gas that is a major component of photochemical smog.
It can cause and aggravate respiratory illness.
Can aggravate heart disease.
Damage plants, rubber in tires, fabrics, and paints
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Aim15: Outdoor Air Pollution
3. Other Air Pollutants
C. Volatile Organic Compounds
Most are hydorcarbons emitted by the leaves of many plants and methane.
About two thirds of global methane emissions comes from human sources.
Other VOCs include industrial solvents such as trichlorethylene (TCE), benzene, and vinyl chloride.
Long­term exposure to benzene can cause cancer, blood disorders, and immune system damage
3. Other Air Pollutants
D. Radon
Is a naturally occurring radioactive gas found in some types of soil and rock.
It can seep into homes and buildings sitting above such deposits.
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Aim15: Outdoor Air Pollution
3. Other Air Pollutants
E. Lead
Indestructible and potent Neurotoxin
Can cause: partial paralysis, blindness, mental retardation or death
Mostly affects children
4. SMOG
A. Industrial smog is a mixture of sulfur dioxide, droplets of sulfuric acid, and a variety of suspended solid particles emitted mostly by burning coal.
In most developed countries where coal and heavy oil is burned, industrial smog is not a problem due to reasonably good pollution control or with tall smokestacks that transfer the pollutant to rural areas.
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Aim15: Outdoor Air Pollution
B. Photochemical smog is a mixture of air pollutants formed by the reaction of nitrogen oxides and volatile organic hydrocarbons under the influence of sunlight.
5. Factors that affect outdoor air pollution
A. Increased by
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Aim15: Outdoor Air Pollution
5. Factors that affect outdoor air pollution
B. Decreased by
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Aim15: Outdoor Air Pollution
6. Acid Deposition
A. Definition
Acid deposition consists of rain, snow, dust, or gas with a pH lower than 5.6
Apr 16­9:07 PM
B. Effects
Acid deposition contributes to chronic respiratory disease and can leach toxic metals (such as lead and mercury) from soils and rocks into acidic lakes used as sources for drinking water.
Apr 16­9:09 PM
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Aim15: Outdoor Air Pollution
C. Impact on the US
Apr 16­9:09 PM
D. Treatment vs. Prevention
Apr 16­9:10 PM
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Aim15: Outdoor Air Pollution
7. The Clean Air Acts
A. Years
7. The Clean Air Acts
B. What they do
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Aim15: Outdoor Air Pollution
7. The Clean Air Acts
C. Effects
7. The Clean Air Acts
D. Major Criticisms
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