Major Air Pollutants Clean Air Act – EPA Air Pollution During the 1950’s and 1960’s, most factories looked like this.
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Major Air Pollutants Clean Air Act – EPA Air Pollution During the 1950’s and 1960’s, most factories looked like this Air Pollution The term “Smog” (smoke and fog) was first used in 1905 to describe sulfur dioxide emission In 1952, severe pollution took the lives of 5000 people in London “It isn’t pollution that’s harming the environment. It’s the impurities in our air and water that are doing it.” Former U.S. Vice President Dan Quayle Air Pollution Natural sources of air pollution are often made worse by human activity. Land use policies ‘Slash and burn’ agriculture Build up of fuel wood from fire suppression in U.S. national forests Air Pollution Anthropogenic (human caused) air pollution Point sources 1. Coal-fired power plant’s smokestack Non-Point sources 2. Automobiles Air Pollution Primary air pollutants Come directly out of a smokestack or exhaust pipe Carbon monoxide Carbon dioxide Sulfur dioxide Nitrous oxides Most suspended particulate matter Secondary air pollutants Have undergone chemical change or transformation in the presence of sunlight with water or with oxygen in the atmosphere Sulfuric acid Ozone Where do the air pollutants come from? Major Sources of Primary Pollutants Stationary Sources Combustion of fuels for power and heat – Power Plants Other burning such as Wood & crop burning or forest fires Industrial/ commercial processes Solvents and aerosols Mobile Sources Highway: cars, trucks, buses and motorcycles Off-highway: aircraft, boats, locomotives, farm equipment, RVs, construction machinery, and lawn mowers Human Impact on Atmosphere Refining petroleum and burning fossil fuels and manufacturing Adds CO2 and O3 to troposphere Climate Change Produces Acid Rain Releases SO2 into troposphere Releases toxic heavy metals (Pb, Cd, and As) into troposphere Using Nitrogen fertilizers and burning fossil fuels Releases NO, NO2, N2O, and NH3 into troposphere Produces acid rain Where are we at today? There are six criteria air pollutants established by the EPA Carbon Oxides Nitrogen Oxides Particulate matter Lead Sulfur Oxides Tropospheric Ozone (ground) Major Air Pollutants Carbon oxides Properties colorless, odorless, heavier than air, 0.0036% of atmosphere highly toxic gas that forms during the incomplete combustion of carboncontaining materials. Sources incomplete combustion of fossil fuels 60 95% from auto exhaust Carbon monoxide (CO) is a 93% of carbon dioxide (CO2) in the troposphere occurs as a result of the carbon cycle. 7% of CO2 in the troposphere occurs as a result of human activities (mostly burning fossil fuels). Effects binds tighter to Hgb than O2 Impairs mental functions and visual acuity, even at low levels EPA Standard: 9 ppm 5.5 billion tons enter atmosphere/year Mobile Source Emissions - CO Major Air Pollutants Suspended particulate matter (SPM) Properties Consists of a variety of solid particles and liquid droplets small and light enough to remain suspended in the air. The most harmful forms of SPM are fine particles (PM-10, with an average diameter < 10 micrometers) and ultrafine particles (PM-2.5). Sources Burning coal or diesel Volcanoes Asbestos PCBs, dioxins, pesticides unpaved roads, plowing, burning fields lint, pollen, spores Effects lung damage, mutagenic, carcinogenic, teratogenic EPA Standard: 50 ug/m3 (annual mean) SPM is responsible for about 60,000 premature deaths a year in the U.S. Mobile Source Emissions: Fine Particulate Matter (PM2.5) Major Air Pollutants Nitrogen oxides • • • • Properties • Reddish brown gas • NO reacts with air to form NO2. • NO2 reacts with water vapor in the air to form nitric acid (HNO3) and nitrate salts (NO3-) which are components of acid deposition. Sources • lightening and certain soil bacteria. • fossil fuels combustion at high temperatures • power plants, forest fires, volcanoes, bacteria in soil Effects • acid rain • lung and heart problems • decreased visibility (yellow haze) • suppresses plant growth EPA Standard: 0.053 ppm Mobile Source Emissions: Nitrogen Oxides Major Air Pollutants Lead Properties Heavy metal Effects Is a powerful neurotoxin. accumulates in tissue affects kidneys, liver and nervous system (children most susceptible) mental retardation possible carcinogen; 20% of inner city kids have high levels Sources particulates, smelters, batteries Was removed from gasoline over three decades ago Concentrations in the air have declined precipitously Mercury from coal fired power plants is now of greater concern than lead EPA Standard 1.5 ug/m3 2 million tons enter atmosphere/year Major Air Pollutants Volatile organic compounds (VOCs) Properties Most are hydrocarbons emitted by the leaves of many plants and methane Organic compounds that evaporate easily, usually aromatic Benzene Chlorofluorocarbons (CFCs Sources Vehicles (largest source), evaporation of solvents or fossil fuels, aerosols, paint thinners, dry cleaning About two thirds of global methane emissions comes from human sources. Other VOCs include industrial solvents such as trichlorethylene (TCE), benzene, gasoline, paint thinner, and vinyl chloride. Effects Long-term exposure to benzene can cause cancer, blood disorders, and immune system damage. eye and respiratory irritants Carcinogenic Liver, CNS, or kidney damage Damages plants Lowered visibility due to brown haze Global warming Major Air Pollutants Sulfur dioxide (SO2) Properties colorless gas with irritating odor Sources About one-third of SO2 in the troposphere occurs naturally through the sulfur cycle. Two-thirds come from human sources, mostly combustion (S+ O2 SO2) of sulfur-containing coal and from oil refining and smelting of sulfide ores, paper manufacture Effects produces acid rain (H2SO4), breathing difficulties, eutrophication due to sulfate formation (lichen and moss are indicators) EPA Standard: 0.3 ppm (annual mean) Ozone (O3) Major Air Pollutants Properties colorless, unpleasant odor highly reactive gas major component of photochemical smog Sources Created by sunlight acting on NOx and VOC Photocopiers, chemical solvents Cars Industry Incomplete fuel combustion products Effects Lung irritant Cause and aggravate respiratory illness Can aggravate heart disease Eyes Damage plants, rubber in tires, fabrics, and paints 0.1 ppm can lower PSN by 50% 10,000 to 15,000 people in US admitted to hospitals each year due to ozone-related illness Children more susceptible Airways narrower More time spent outdoors Mobile Source Emissions: Hydrocarbons – Precursors to Ozone Sunlight plus Cars Equals Photochemical Smog Mexico City is one of the many cities in sunny, warm, dry climates with many motor vehicles that suffer from photochemical smog. Sunlight plus Cars Equals Photochemical Smog Photochemical smog is a mixture of air pollutants formed by the reaction of nitrogen oxides and volatile organic hydrocarbons under the influence of sunlight. Clean Air Act of 1963 Congress found: Most people now live in urban areas Growth results in air pollution Air pollution endangers living things It decided: Prevention and control at the source was appropriate Such efforts are the responsibility of states and local authorities Federal funds and leadership are essential for the development of effective programs Clean Air Act Originally signed 1963 States controlled standards 1970 – Uniform Standards by Federal Govt. Standards were stricter Limits on emissions New funding Pollution control research Citizens could sue Criteria Pollutants Primary – Human health risk Secondary – Protect materials, crops, climate, visibility, personal comfort Clean Air Act 1990 version Strengthened regulations pertaining to air quality standards Set nation wide standards for emissions of the six “criteria pollutants” Left it up to the States to regulate and monitor Emissions trading program introduced (Cap and Trade) Total emissions have declined by 60% despite substantial increases in energy consumption, miles traveled by vehicles and gross domestic product Clean Air Act 1990 Policy changes and developments Catalytic converters - Required on all new U.S. autos since 1975 Scrubbers – use a combination of air and water that separates and removes particulates and SO2 before they are emitted from smokestacks Leaded gasoline – phase out caused U.S. lead emissions to plummet by 93% in the 1980’s alone Electrostatic precipitators – installed in smokestacks use an electrical charge to make particulates coalesce to that they can be physically removed Clean Air Act 1997 version Reduced ambient ozone levels Cost $15 billion/year > save 15,000 lives Reduce bronchitis cases by 60,000 per year Reduce hospital respiratory admission 9000/year Clean Air Act 2007 U.S. Supreme Court ruled that carbon dioxide should be considered an air pollutant under the Clean Air Act 2009 EPA proposed that it should be considered an air pollutant at some point in the future General Status of Global Air Quality Some pollutants are not declining, some new air pollutants are emerging and green house gas emissions continue to rise CO2 rose 44% from 1970 to 2008 Industrializing nations such a China and India are suffering increasing air pollution problems China has fueled its rapid industrial development with its abundant reserves of coal. Brown Cloud Rural issue – great deal of air pollution emanates from feedlots (dust, methane, hydrogen sulfide, ammonia South Asia’s Massive Brown Cloud A huge dark brown cloud of industrial smog, caused by coal-burning in countries such as China and India, stretches over much of southeastern Asia. In areas beneath the cloud, photosynthesis is reduced interfering with crop development. Fine particles and droplets in the cloud appear to be changing regional climates (including rainfall). May have contributed to floods in 2002 and 2005 which killed thousands of people. Hopefully Not The End