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Chemistry 173 Atmospheric Chemistry

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Chemistry 173 Atmospheric Chemistry Powered By Docstoc
					Ground-Level
Air Pollution
                           SMOG

• Smog: combination of smoke and fog
• Smoke + fog (London-type) Smog
  – results from the burning of coal and other raw materials
    in the presence of a fog


• Photochemical (Los Angeles-type) Smog
  – results from the emissions of hydrocarbons and oxides
    of nitrogen in the presence of sunlight
                 London-type smog
• Several deadly London-type smog events in the 19th
  and 20th centuries, such as the one on
  December 1952 (London): >4000 deaths!
              Photochemical (LA) smog
• “soup” of gases and aerosol particles
• some of the substances are emitted (primary
  pollutants) whereas others form chemically or
  physically in the air (secondary pollutants)
• involves hundreds of different reactions (“giant
  chemical reactor”)
• sunshine: vital ingredient
• relatively little movement of the air masses
• relatively high levels of ozone at ground level
  (“ozone in the wrong place”)
121
                 Source/Receptor Regions in




                           Volume mixing ratio (ppmv)
                        Los Angeles
0.3                                                              0.3
            Central Los Angeles                                        San Bernardino
             August 28, 1987                                           August 28, 1987      O (g)
                                                                                                3
0.2                                                              0.2
         NO(g)
                  NO (g)                                                       NO (g)
                     2                                                           2

0.1                                                O (g)         0.1
                                                        3



                                                                        NO(g)
 0                                                                0
     0       6      12      18                              24     0       6       12      18       24
                 Hour of day                                                     Hour of day
          Particulates in Air Pollution




Although most regulations of air pollution focus on gases,
aerosol particles cause more visibility degradation and possibly
more health problems than gases.
Aerosols: liquid and solid particles suspended in the air
- Natural and Anthropogenic Sources
Visibility Degradation
Health Effects of Air Pollutants
                Health Effects of Air Pollutants

•   Lung functions
•   Lung growth
•   Irregularities in heartbeats
•   Long-term [chronic] exposure
•   Respiratory illness
•   Asthmatic attacks
•   Angina pain
•   Hospital admissions
•   Emergency room visits
•   Pulmonary deaths
•   Cardiovascular deaths
Health Effects of Outdoor Air Pollutants
          Gaseous Pollutants
                    Regulation in the U.S.

•   Air Pollution Act of 1955
•   Clean Air Act of 1963
•   Motor Vehicle Air Pollution Control Act of 1965
•   Air Quality Act of 1967
•   Clean Air Act Amendments of 1970
•   Clean Air Act Amendments of 1977
•   Clean Air Act Amendments of 1990
•   Clean Air Act Revision of 1997
•   New Clean Air Act Regulations (2002/2003)
•   New Source Review (NSR) modification
            INDOOR AIR POLLUTION


Although epidemiological studies have found an
association between short-term exposure to outdoor
particulate air pollution and health problems,
people spend most of their times indoors, and
concentrations of aerosol particles are often greater
indoors than outdoors.
Sources of Major Indoor Air Pollutants

				
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posted:9/28/2012
language:English
pages:27