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Air pollution

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Che Che

on 25 September 2012

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Transcript of Air pollution

9.5AIR POLLUTION human activities can influence
global climate processes we discuss more direct and immediate health an environmental effects of air quality American release about 150 million metric tons of air pollution (not counting carbon dioxide or wind-blown soil) each year Worldwide emission of these pollutants are around 2 billion metric tons per year. Environmental Protection
Agency (EPA) The EPA estimates that,since 1990. when regulation of the most hazardous materials began, air toxics, emissions have been reduced more than 1 million tons per year. Pollution reductions have resulted mainly from greater efficiency and pollution-control technologies in factories, power plants and automobiles. 3 km (2mi) thick toxic cloud/year =
up to 2 million death toll. ash
photochemical reactants We describe pollutants according to sources Clean Air Act of 1970 A point source is a smokestack or some other concentrated pollution origin. Primary pollutants are released in harmful form Secondary
pollutants by contrast, become hazardous after reactions in the air. Photochemical oxidants (compounds created by reactions driven by solar energy) and atmospheric acids are are probably the most important secondary pollutants. Fugitive, or non-point-source,
emissions -are those that do not go through a smokestack. sulfur dioxide
carbon monoxide
volatile organic compounds
nitrogen oxides
lead Conventional or Criteria, pollutants : the most serious threat of all air pollutants to human health and welfare. Any visible or invisible particle or gas found in the air that is not part of the original, normal composition. unconventional pollutants: asbestos
polychlorinated biphenyls(PCBs)
vinyl chloride Conventional pollutants are
common and serious carbon monoxide (CO) Lead and other toxic elements particulate material nitrogen oxide (NO ) volatile organic compounds (VOC ) sulfur dioxide (SO ) (cc) image by nuonsolarteam on Flickr 2 -is a colorless, corrosive gas that damages both plants and animals. 2 -are highly reactive gases formed when combustion initiates reactions between atmospheric nitrogen and oxygen -is less common but more dangerous than the principal for atmospheric carbon, carbon dioxide (CO ) 2 -includes dust, ash, soot, lint, smoke, pollen, spores, algal cells, and many other suspended materials. -are organic (carbon containing) gases. s -toxic metal and halogens are chemical elements that are toxic when concentrated and released in the environment Indoor air can be more dangerous than outdoor air The U.S EPA has found that indoor concentra- tions of toxic air pollutants are often higher than outdoors Under some circumstances, compounds such as chloroform, benzene, carbon tetrachloride, formaldehyde, and styrene can be 70 times higher in indoor air than in outdoor air. Cigarette smoke is without doubt the most important air contaminant in developed countries in terms of human health. the US surgeon general has estimated that 400,000 people DIE each year in the United States from emphysema, heart attacks, strokes, lung cancer, or other diseases caused by.. SMOKE 9.6 Interactions Between Climate and Air Pollution Air pollutants can travel far Dust and fine aerosols can be carried great distances by the wind. - in one particularly severe dust storm in 1998, chemical analysis showed that 75 percent of the particulate pollution in Seattle, Washington, air came from China. Similarly, dust from North Africa regularly crosses the Atlantic and contaminates the air in Florida and the Caribbean islands.
-this dust can carry pathogens and is thought to be the source of diseases attacking Caribbean corals.
-Soil scientist estimate that 3 billion tons of sand ad dust are blown around the world every year. fig. 9.22 A massive dust storm extends more than 1,600 km (1,000 mi) from the coast of western Sahara and Morocco. Storms such as this can easily reach the Americas, and they have been linked both
to the decline of coral reefs in the Caribbean and to the frequency and intensity of hurricanes formed in the eastern Atlantic Ocean. Ozone in the stratosphere is harmed by CFCs Long range pollution transport and the chemical reactions of atmospheric gases and pollution produce by the phenomenon known as the ozone hole. CFC control has shown remarkable success
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