Lect 25 Air Pollution PP outline

Lect 25 Air Pollution PP outline - Air Pollution THE AIR...

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Air Pollution THE AIR AROUND US Approximately 147 million metric tons of air pollution are released annually into the atmosphere in the U.S. by human activities. Worldwide emissions total around 2 billion metric tons. Developed countries have been improving air quality, while air quality in developing world is getting worse. NATURAL SOURCES OF AIR POLLUTION Natural Fires - Smoke Volcanoes - Ash and acidic components Sea Spray - Sulfur Vegetation - Volatile organic compounds Bacterial Metabolism - Methane Dust Pollen Viruses and Bacteria HUMAN-CAUSED AIR POLLUTION Primary Pollutants - Released directly from the source. Secondary Pollutants - Modified to a hazardous form after entering the air and mixing with other environmental components. Fugitive Emissions - Do not go through smokestack. - Dust from human-activities. Conventional Pollutants U.S. Clean Air Act designated seven major (conventional or criteria) pollutants for which maximum ambient air levels are mandated. Sulfur Dioxide Nitrogen Oxides Carbon Monoxide Particulate Matter Hydrocarbons Photochemical Oxidants Lead Conventional Pollutants Sulfur Compounds Natural sources of sulfur in the atmosphere include evaporation from sea spray, volcanic fumes, and organic compounds. Predominant form of anthropogenic sulfur is sulfur-dioxide from fossil-fuel combustion. - Annual Emissions: 114 million metric tons Conventional Pollutants Nitrogen Compounds Nitrogen oxides are reactive gases formed when nitrogen is heated above 650 o C in the presence of oxygen, or when nitrogen compounds are oxidized. - Annual Emissions: 230 million metric tons Conventional Pollutants Carbon Oxides Predominant form of carbon in the air is carbon dioxide. -
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Lect 25 Air Pollution PP outline - Air Pollution THE AIR...

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