Air and Air PollutionAir and Air Pollution

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

The AtmosphereThe Atmosphere

Troposphere: 75-80% of mass of the atmosphere

Troposphere: 75-80% of mass of the atmosphere

Stratosphere: much less H2O(v), and much more O3.

Stratosphere: much less H2O(v), and much more O3.

78% N, 21% O, 1-4% H2O(v), 1% Ar and .037%CO2

78% N, 21% O, 1-4% H2O(v), 1% Ar and .037%CO2

Ozone layer: Beneficial in the stratosphere damaging in the troposphere (smog).

Ozone layer: Beneficial in the stratosphere damaging in the troposphere (smog).

Greenhouse effect: necessary for life

Greenhouse effect: necessary for life

Fig. 17-2 p. 419/ see also fig. 17-3 p. 420Fig. 17-2 p. 419/ see also fig. 17-3 p. 420

8-17 km

Outdoor Air PollutionOutdoor Air Pollution Primary pollutants:

from both natural and human (anthropogenic) sources

Primary pollutants: from both natural and human (anthropogenic) sources

Secondary pollutants: from chemical reactions that occur in the atmosphere with the primary pollutants

Secondary pollutants: from chemical reactions that occur in the atmosphere with the primary pollutants

See Table 17-1 p. 420See Table 17-1 p. 420See Table 17-2 p. 422See Table 17-2 p. 422

Fig. 17-4 p. 421

Indoor Pollutants:Come from infiltration from outside polluted air and various chemicals used or produced inside buildings

Indoor Pollutants:Come from infiltration from outside polluted air and various chemicals used or produced inside buildings

Photochemical SmogPhotochemical Smog Brown-air smog

due to NO2

Brown-air smog due to NO2

Photochemicalreactions (see pg. 423-424)

Photochemicalreactions (see pg. 423-424)

Photochemicaloxidants (PAN’s, NO2, and O3 )

Oxidize compounds in air or lungs Irritate lungs, damage plants

Photochemicaloxidants (PAN’s, NO2, and O3 )

Oxidize compounds in air or lungs Irritate lungs, damage plants

Fig. 17-6 p. 424

Factors that influence: topography, population density, industry, fuels used, urbanization, high temperatures

Photochemical SmogPhotochemical Smog• At the high temperatures of the car's combustion chamber (cylinder), nitrogen and oxygen

from the air react to form nitric oxide (NO):

Step 1: N2 + O2 -----> 2NO

• Some of the nitric oxide (NO) reacts with oxygen to form nitrogen dioxide NO2):

Step 2: 2NO + O2 -----> 2NO2

• When the nitrogen dioxide (NO2) concentration is well above clean air levels and there is plenty of sunlight, then an oxygen atom splits off from the nitrogen dioxide molecule:

Step 3: NO2 ---------->NO + O (sunlight)

• This oxygen atom (O) can react with oxygen molecules (O2) in the air to form ozone (O3):

Step 4: O + O2 -----> O3 (ozone)

Industrial SmogIndustrial Smog

Gray-air smog: Suspended particles and soot

Gray-air smog: Suspended particles and soot

Industrial smog: largely due to burning of coal and release of sulfur impurities

Industrial smog: largely due to burning of coal and release of sulfur impurities

Sulfuric acidSulfuric acid

Sulfur dioxideSulfur dioxideParticulates: < 10

microns dangerous to health

Particulates: < 10

microns dangerous to health Fig. 17-8 p. 426Fig. 17-8 p. 426

See pg. 423

Temperature InversionsTemperature Inversions Subsidence inversion:

Warm air mass moves over a cold air mass and decreases vertical mixing

Subsidence inversion: Warm air mass moves over a cold air mass and decreases vertical mixing

Radiation inversion: occurs at night, air near ground cools faster than air above. Sun rise heats up the air and usually diminishes by noon

Radiation inversion: occurs at night, air near ground cools faster than air above. Sun rise heats up the air and usually diminishes by noon

Fig. 17-9 p. 427Fig. 17-9 p. 427

Slide 12Slide 12Slide 12Slide 12Slide 12Slide 12Slide 12Slide 12Slide 12Slide 12Slide 12Slide 12Slide 12Slide 12Slide 12Slide 12

Inversion layer

Mountainrange

Sea breeze

Descending warm air mass

Decreasing temperature

Inc

reas

ing

alt

itu

de

Figure 17-9 (2)Page 427

Regional Outdoor Air Pollution from Acid DepositionRegional Outdoor Air Pollution from Acid DepositionAcid deposition: due to tall smokestacks pollution is

decreased locally and increased regionally and transformed in the atmosphere as it is spread downwind and deposited as acid deposition

Acid deposition: due to tall smokestacks pollution is decreased locally and increased regionally and transformed in the atmosphere as it is spread downwind and deposited as acid deposition

Wet deposition: acid rain snow fog and cloud vapor

Wet deposition: acid rain snow fog and cloud vapor

Dry deposition: acidic particles

Dry deposition: acidic particles

Fig. 17-10 p. 428

Acid Deposition in the USAcid Deposition in the US

Fig. 17-11 p. 429

Acid Deposition and HumansAcid Deposition and Humans

Respiratory diseases Respiratory diseases

Toxic metal leaching Toxic metal leaching

Decreased visibility Decreased visibility

Damage to structures, especially containing limestone

Damage to structures, especially containing limestone

Decreased productivity and profitability of fisheries, forests, and farms

Decreased productivity and profitability of fisheries, forests, and farms

Acid Deposition and Aquatic SystemsAcid Deposition and Aquatic Systems

Fish declines Fish declines

Undesirable species

Undesirable species

Aluminum toxicity

Aluminum toxicity

Fig. 17-14 p. 431Fig. 17-14 p. 431

Acid Deposition, Plants, and SoilAcid Deposition, Plants, and Soil

Nutrient leaching

Nutrient leaching

Heavy metal release

Heavy metal release

Weakens trees Weakens trees

Fig. 17-15 p. 432Fig. 17-15 p. 432

Prevention Cleanup

Reduce air pollutionby improving energyefficiency

Reduce coal use

Increase natural gasuse

Increase use of renewable resources

Burn low-sulfur coal

Remove SO2 particulates, and NOx

from smokestack gases

Remove Nox frommotor vehicular exhaust

Tax emissions of SO2

Add lime to neutralizeacidified lakes

Add phosphatefertilizer to neutralizeacidified lakes

Figure 17-16Page 433

Indoor Air Pollution/Sick Building SyndromeIndoor Air Pollution/Sick Building Syndrome

Fig. 17-17p. 434

RadonRadon

Radon-222 Radon-222

4 picocurie level 4 picocurie level

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. 17-18

p. 436

Effects of Air Pollution on Living Organisms and MaterialsEffects of Air Pollution on Living Organisms and Materials

Damage to mucous membranesDamage to mucous membranes

Respiratory diseases (see Fig. 17-19 p. 438)Respiratory diseases (see Fig. 17-19 p. 438)

Damage to plant leaves and rootsDamage to plant leaves and roots

Reduction in primary productivityReduction in primary productivity

Deterioration of materials (See Table 17-3 p. 440)

Deterioration of materials (See Table 17-3 p. 440)

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

Clean Air Act: passed 1970, 1977, and 1990Clean Air Act: passed 1970, 1977, and 1990

National Ambient Air Quality Standards (NAAQS)

National Ambient Air Quality Standards (NAAQS)Primary and secondary

standards: primary set to protect human health; secondary set to prevent environmental and property damage

Primary and secondary standards: primary set to protect human health; secondary set to prevent environmental and property damage

Emission ReductionEmission Reduction

Fig. 17-22 p. 441Fig. 17-22 p. 441

Fig. 17-23a p. 442Fig. 17-23a p. 442