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Air_pollution_ppt.ppt
1.
2. A Brief History of Air Pollution
๏ฎ Air pollution not a new problem
๏ฎ Smoke problems:
โ Caves
โ 1273 King Edward I
โ 1661 London
โ 1873 700 killed in London
โ 1911 smog killed 1150 Londoners
14. Types and Sources of Air Pollutants
๏ฎ Ozone in the Troposphere
โ Photochemical smog or oxidants
โ Ground level ozone
โ Sunlight dissociates which eventually causes
oxygen to combine and form ozone
โ Bad ozone
๏ฎ Ozone in the Stratosphere
โ Stratospheric ozone absorbs UV radiation; one
reason for increase in temperature in sphere
โ Good ozone
16. Types and Sources of Air Pollutants
๏ฎ Ozone in the Stratosphere
โ Production-Destruction: ozone forms naturally
though combination of atomic oxygen with
molecular oxygen, absorbs UV radiation and
breaks down; creates balance
โ Upsetting the Balance: anthropogenic
chemicals nitrogen oxide and
chlorofluorocarbons destroy ozone, disrupt
balance and create ozone hole
17. Types and Sources of Air Pollutants
๏ฎ Air Pollution: Trends and Patterns
โ Clean Air Act 1970 has decreased air pollution
in the US, greatest reduction in lead
(unleaded gasoline)
โ Increase in number of autos negates impact
of Act is some areas
โ Air quality index
โ Primary and Secondary National Ambient Air
Quality Standards
22. Types and Sources of Air Pollutants
๏ฎ Environmental Issue: The Ozone Hole
โ The lowest concentration or ozone hole
covers most of Antarctica, but varies in
coverage and intensity from year to year.
23. Factors that Affect Air Pollution
๏ฎ The Role of Wind
โ Dilution of pollution dependent upon wind
speed
๏ฎ The Role of Stability and Inversions
โ Vertical mixing
โ Radiation inversion
โ Mixing layer
โ Mixing depth
31. Factors that Affect Air Pollution
๏ฎ Observation: Smoke stacks
โ Instability and wind impact pollution from
smoke stacks
๏ง Fanning
๏ง Fumigation
๏ง Looping
๏ง Coning
๏ง Lofting
32. Factors that Can Affect Air Pollution
๏ฎ The Role of Topography
โ Mountains, valleys, and coasts and the
orientation to prevailing winds can exacerbate
air pollution.
โ Denver, Los Angeles
36. Factors that Affect Air Pollution
๏ฎ Severe Air Pollution
โ Ingredients
๏ง Many sources of pollution
๏ง Stationary high pressure
๏ง Light surface winds
๏ง Subsidence inversion
๏ง Shallow mixing layer
๏ง Valley
๏ง Clear night
๏ง smog
37. Air Pollution and the Urban
Environment
๏ฎ Urban heat island
๏ฎ Country breeze
๏ฎ METROMEX
39. Acid Deposition
๏ฎ Rain combines with sulfur dioxide and
nitrogen oxides to create sulfuric and nitric
acid
๏ฎ Acidic deposition damages ecosystems,
particularly lakes, and buildings
๏ฎ Coal burning plants in Ohio Valley are
source, greatest damage in Adirondacks
43. Observation: Donora
๏ฎ Eastern Pennsylvania
๏ฎ Oct 26, 1948
๏ฎ Fog + anticyclone + temperature inversion
+ industrial plants
๏ฎ 22 deaths, 7000 illnesses
Editor's Notes
Figure 14.1: The fog and smoke were so dense in London during December, 1952, that visibilities were often restricted to less than 100 feet and streetlights had to be turned on during the middle of the day.
Figure 14.2: Strong northeasterly Santa Ana winds on October 28, 2003, blew the smoke from massive wildfires across southern California out over the Pacific Ocean.
Figure 14.3: (a) Estimates of emissions of the primary air pollutants in the United States on a per weight basis. (b) The primary sources for the pollutants. (Data courtesy of United States Environmental Protection Agency.)
Figure 14.3: (a) Estimates of emissions of the primary air pollutants in the United States on a per weight basis. (b) The primary sources for the pollutants. (Data courtesy of United States Environmental Protection Agency.)
Figure 14.3: (a) Estimates of emissions of the primary air pollutants in the United States on a per weight basis. (b) The primary sources for the pollutants. (Data courtesy of United States Environmental Protection Agency.)
Figure 14.4: (a) Denver, Colorado, on a clear day, and (b) on a day when particulate matter and other pollutants greatly reduce visibility.
Figure 14.4: (a) Denver, Colorado, on a clear day, and (b) on a day when particulate matter and other pollutants greatly reduce visibility.
Figure 14.5: A thick haze about 200 km wide and about 600 km long covers a portion of the East China Sea on March 4, 1996. The haze is probably a mixture of industrial air pollution, dust, and smoke.
Figure 14.6: Cumulus clouds and a thunderstorm rise above the thick layer of haze that frequently covers the eastern half of the United States on humid summer days.
Figure 7.9: Average annual precipitation for Cherrapunji, India. Note the abundant rainfall during the summer monsoon (April through October) and the lack of rainfall during the winter monsoon (November through March).
Figure 14.10: Emission estimates of six pollutants in the United States from 1940 through 2003. (Data courtesy of United States Environmental Protection Agency.)
Figure 14.11: The number of unhealthful days (by county) across the United States for any one of the five pollutants (CO, SO2, NO2, O3, and particulate matter) during 2008. (Data courtesy of United States Environmental Protection Agency.)
Figure 14.12: The number of days ozone exceeded the 8-hour federal standard (0.08 ppm) and maximum 8-hour ozone concentration (ppm) for Los Angeles and surrounding areas in the South Coast air basin. (Courtesy of South Coast Air Pollution District.)
Figure 14.13: If each chimney emits a puff of smoke every second, then where the wind speed is low (a), the smoke puffs are closer together and more concentrated. Where the wind speed is greater (b), the smoke puffs are farther apart and more diluted as turbulent eddies mix the smoke with the surrounding air.
Figure 14.13: If each chimney emits a puff of smoke every second, then where the wind speed is low (a), the smoke puffs are closer together and more concentrated. Where the wind speed is greater (b), the smoke puffs are farther apart and more diluted as turbulent eddies mix the smoke with the surrounding air.
Figure 14.13: If each chimney emits a puff of smoke every second, then where the wind speed is low (a), the smoke puffs are closer together and more concentrated. Where the wind speed is greater (b), the smoke puffs are farther apart and more diluted as turbulent eddies mix the smoke with the surrounding air.
Figure 14.14: (a) During the afternoon, when the atmosphere is most unstable, pollutants rise, mix, and disperse downwind. (b) At night when a radiation inversion exists, pollutants from the shorter stacks are trapped within the inversion, while pollutants from the taller stack, above the inversion, are able to rise and disperse downwind.
Figure 14.14: (a) During the afternoon, when the atmosphere is most unstable, pollutants rise, mix, and disperse downwind. (b) At night when a radiation inversion exists, pollutants from the shorter stacks are trapped within the inversion, while pollutants from the taller stack, above the inversion, are able to rise and disperse downwind.
Figure 14.14: (a) During the afternoon, when the atmosphere is most unstable, pollutants rise, mix, and disperse downwind. (b) At night when a radiation inversion exists, pollutants from the shorter stacks are trapped within the inversion, while pollutants from the taller stack, above the inversion, are able to rise and disperse downwind.
Figure 14.15: A strong subsidence inversion along the coast of California. The base of the stable inversion acts as a cap or lid on the pollutants below by preventing them from escaping into the warmer air above. If the inversion lowers, the mixing depth decreases, and the pollutants are concentrated within a smaller volume.
Figure 14.16: A thick layer of polluted air is trapped in the valley. The top of the polluted air marks the base of a subsidence inversion and the top of the mixing layer.
Figure 14.18: At night, cold air and pollutants drain downhill and settle in low-lying valleys.
Figure 14.19: A thick layer of smog covers the city of Los Angeles.
Figure 14.20: On a clear, relatively calm night, a weak country breeze carries pollutants from the outskirts into the city, where they concentrate and rise due to the warmth of the cityโs urban heat island. This effect may produce a pollution (or dust) dome from the suburbs to the center of town.
Figure 14.21: The pH scale ranges from 0 to 14, with a value of 7 considered neutral. Values greater than 7 are alkaline and below 7 are acidic. The scale is logarithmic, which means that rain with pH 3 is 10 times more acidic than rain with pH 4 and 100 times more acidic than rain with pH 5.
Figure 14.22: Values of pH in precipitation over the United States during 2005. (National Atmospheric Deposition Program)
Figure 14.23: The effects of acid fog in the Great Smoky Mountains of Tennessee.
