CE 326 Principles of Environmental Engineering Prof. Tim Ellis

Transcription

1 AIR POLLUTION CE 326 Principles of Environmental Engineering Prof. Tim Ellis January 23, 2009

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4 Seven Major Pollutants of Concern 1. P 2. S Oxides (SO X ) 3. O 4. N Oxides (NO X ) 5. Carbon M (CO and other hyrdrocarbons) 6. Volatile O Compounds (VOCs) 7. L (& others: mercury, other inorganic metals, radon, HCl) CE 326 Principles of Environmental Engineering, Copyright 2008 Tim Ellis, Iowa State University

5 Particulates released d into the air largely a result of s sources a nearly u urban pollutant. Although particulate levels in North America and Western Europe rarely exceed 50 micrograms of particulate matter per cubic meter (µg/m 3 ) of air, levels in many Central and Eastern European cities and in many developing nations are much higher, often exceeding 100 μg/m 3 ( en.epochtimes.com/news_images/ airpollution.jpg

6 Global distribution of urban PM 10 concentrations Sweden France Canada United States Venezuela Greece South Africa Kenya Argentina Egypt Italy Ecuador Brazil Nicaragua Colombia Costa Rica Panama Mexico Ghana Honduras Guatemala Chile Nepal Thailand Iran, Islamic Rep China India Indonesia Nigeria Pakistan Adapted from Reference Cumulative percentage of urban population 0 % 20 % 40 % 60 % 80 % 100 % Urban population Annual concentration Population-weight PM 10 concentrations g/m 3

7 Size of Particulates PM : 2.5 to 100 μ in diameter, usually comprise s and d from industrial processes, agriculture, c and road traffic, p p, and other natural sources. PM 2.5 : particles less than 2.5 μ in diameter generally come from combustion of f fuels. vehicle exhaust s, which is often coated with various chemical contaminants fine sulfate and nitrate a that form when SO 2 and nitrogen oxides condense in the atmosphere. largest source of fine particles is c -fired power plants, but auto and diesel e are also prime contributors, tib t especially along busy transportation t ti corridors. CE 326 Principles of Environmental Engineering, Copyright 2008 Tim Ellis, Iowa State University

8 Health Effects S particulates most damaging (PM 2.5 ) PM 2.5 aggravate existing h and lung diseases changes the body's defenses against i materials, and damages l tissue. E, children and those with chronic lung or heart disease are most sensitive lung impairment can persist for 2-3 weeks after e to high levels of PM 2.5 C carried by particulates can also be toxic

9 Science 307: , News Focus, March 2005

10 Sulfur Oxides Sulfur Oxides (SO X, mainly SO 2 ) emitted largely from burning c, high-sulfur o, and d fuel. usually found in association with p SO 2 is the p for fine sulfate particles (separating the health effects of these two pollutants is difficult) SO 2 and particulates make up a major portion of the pollutant l in many cities, acting both separately and in c to damage health. concentrations are higher by a factor of in a number of cities in Eastern Europe, Asia, and South America, where residential or industrial coal use is still prevalent and diesel traffic is heavy major component of a r

11 Health Effects SO 2 affects people q, usually within the first few minutes of e SO 2 exposure can lead to the kind of a health effects typical of particulate pollution. Exposure is linked to an increase in h and deaths from respiratory and cardiovascular causes, especially among a and those with preexisting respiratory diseases severity of these effects increases with rising SO 2 levels, and e enhances the severity by increasing the volume of SO 2 inhaled and allowing SO 2 to penetrate deeper into the respiratory tract Asthmatics may experience w and other symptoms at much lower SO 2 levels than those without asthma. When o is also present, asthmatics become even more sensitive to SO 2 indicating the potential ti for synergistic effects among pollutants

12 Ozone major component of p smog formed when from fuel combustion react with VOCs S and heat stimulate ozone formation, peak levels occur in the s. W in cities in Europe, North America, and Japan as auto and industrial emissions have increased. Many cities in developing countries also suffer from high ozone levels, although few monitoring data exist powerful o, can react with nearly any biological tissue.

13 Ozone concentrations of ppm can irritate the respiratory tract and impair l function, causing coughing, shortness of breath, and c pain. Exercise increases these effects, and heavy exercise can bring on symptoms even at low ozone levels ( ppm). ozone exposure l the body's defenses, increasing susceptibility to respiratory infections As ozone levels rise, hospital a and emergency room visits for respiratory illnesses such as asthma also increase. hospital admissions rise roughly 7 to 10 percent for a 0.05 ppm increase in ozone levels. in 13 cities where ozone levels e U.S. air standards, the American Lung Association estimated that high ozone levels were responsible for approximately 10,000 to 15,000 extra hospital admissions and 30, to 50, additional emergency room v during the ozone season

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15 Preventable health effects due to a 10% reduction of environmental levels of PM 10 and ozone between een 2000 and 2020 cases 10,000,000 1,000,000 Mexico City Sao Paulo Santiago New York 100,000 10,000 1, All ages Child Chronic Asthma Children: mortality bronchitis attacks Acute bronchitis Source: Cifuentes et al, 2001 Mortality Chronic morbidity Morbidity

16 Nitrogen Oxides principal i p component of photochemical smog component of a rain (NO X is oxidized to NO - 3 in the atmosphere, NO - 3 reacts with moisture to form nitric acid H 2 NO 4 ) formed i due to high temperature of combustion of atmospheric nitrogen CE 326 Principles of Environmental Engineering, Copyright 2007 Tim Ellis, Iowa State University

17 Carbon Monoxide H has an affinity for CO that is 200 to 250 times its affinity for oxygen this reduces its affinity for oxygen, disrupts release of oxygen. Blood level of 0.4% is maintained by CO produced by b. Blood is cleared of 50% of CO in 3-4 hours after e. Global emissions of CO are 350 million tons per year, 20% from mobile sources. CO concentration in c smoke is ~400 ppm. 24% of emergency room patients complaining of f -like symptoms in one study showed carbon monoxide poisoning CE 326 Principles of Environmental Engineering, Copyright 2008 Tim Ellis, Iowa State University

18 Carbon Monoxide health effects CO blocks the oxygen transport in your blood. CO is 100x better at binding in the oxygen site. CO poisoning is like suffocating.

19 Volatile Organic Compounds (VOCs) contribute tib t to o generation many are subject to NESHAPS (benzene from gasoline vapors) significant i emissions (e.g., perchloroethylene from dry cleaners) many are c or suspected carcinogens CE 326 Principles of Environmental Engineering, Copyright 2008 Tim Ellis, Iowa State University

20 Other Air Pollutants Lead Mercury other inorganic metals Indoor air pollution Second hand smoke Radon CE 326 Principles of Environmental Engineering, Copyright 2007 Tim Ellis, Iowa State University

21 Pyramid of Effects Death Hospital Admissions $ Doctor visits it Asthma attacks, medication use, symptoms $ lung function changes, immune cell responses, heart rate or heart rate variability responses 21

22 CE 326 Principles of Environmental Engineering, Copyright 2008 Tim Ellis, Iowa State University

23 What is acid rain? More accurate term may be acid d Occurs in two forms w deposition (acidic rain, fog, and snow) d deposition (acidic gases and particles) Principal c are SO X and NO X About of SO X and of NO X comes from power plants (most are coal burning) CE 326 Principles of Environmental Engineering, Copyright 2009 Tim Ellis, Iowa State University

24 How do we measure? ph of natural rain water is (pk a1 of carbonic acid is 6.35) m by two networks, both supported by EPA The National Atmospheric Deposition Program measures w deposition, and its Web site ( d /) features maps of rainfall ph The Clean Air Status and Trends Network (CASTNET) measures d deposition. Its features information about the data it collects, the measuring sites, and the kinds of equipment it uses - CE 326 Principles of Environmental Engineering, Copyright 2007 Tim Ellis, Iowa State University

25 Effects of acid rain damage to forests and soils, fish and other living things, materials, and human health. acidification of l and s In a National Surface Water Survey (NSWS) effects of acidic deposition in over 1,000 lakes larger than 10 acres and in thousands of miles of streams believed to be sensitive to a acid rain caused acidity in percent of the acidic lakes acid rain caused acidity in about percent of fthe acidic streams CE 326 Principles of Environmental Engineering, Copyright 2007 Tim Ellis, Iowa State University

26 Effects of acid rain regions in the U.S. identified as containing many of the s w sensitive to acidification include: the Adirondacks and Catskill Mountains in New York state, the mid-appalachian highlands along the e c, the upper M, and mountainous areas of the Western United States. In areas like the Northeastern United States, where s buffering capacity is poor, some lakes now have a ph value of less than. One of the most acidic lakes reported is Little Echo Pond in Franklin, New York. Little Echo Pond has a ph of. also a problem in lakes smaller than 10 acres that were not included in the NSWS (may increase the number up to f -fold). CE 326 Principles of Environmental Engineering, Copyright 2007 Tim Ellis, Iowa State University

27 Effects of acid rain approximately percent of sensitive lakes in the Adirondacks are at risk of e acidification (brief periods of low ph) low b streams: of the streams in the Mid-Atlantic Coastal Plain are acidic, in the New Jersey Pine Barrens, over percent of the streams are acidic (highest rate of acidic streams in the nation), and over of the streams in the Mid-Atlantic Highlands (mid-appalachia) are acidic, primarily due to acidic deposition. Canadian government has estimated that lakes in eastern Canada are acidic. CE 326 Principles of Environmental Engineering, Copyright 2007 Tim Ellis, Iowa State University

28 Affects Fish and Aquatic Species acid rain causes a c of effects that t harm or k individual fish, reduce fish population p numbers, completely eliminate fish species from a waterbody, and decrease b. increased a levels cause chronic stress that may not kill individual fish, but leads to lower body weight and smaller size and makes fish less able to compete for food and habitat. generally, the y of most species are more sensitive to environmental conditions than adults. At ph 5, most fish eggs cannot hatch. At lower ph levels, some adult fish die. CE 326 Principles of Environmental Engineering, Copyright 2008 Tim Ellis, Iowa State University

29 %20Environmental%20Issues_files/image018.gif CE 326 Principles of Environmental Engineering, Copyright 2007 Tim Ellis, Iowa State University

30 Tree and Forest Damage damage of trees at high e (for example, red spruce trees above 2,000 feet) and many sensitive forest soils. CE 326 Principles of Environmental Engineering, Copyright 2007 Tim Ellis, Iowa State University

31 Water Quality Impacts N impacts on water quality due to eutrophication (o depletion, a blooms, declines in the health of fish and shellfish, loss of seagrass beds and coral reefs, and ecological changes in food webs): percent of the nitrogen produced by various human activities that reaches e and coastal e is transported and deposited via the atmosphere. For example, about percent of the nitrogen in the Chesapeake Bay comes from atmospheric deposition. CE 326 Principles of Environmental Engineering, Copyright 2007 Tim Ellis, Iowa State University

32 Materials and Building Decay a the decay of building materials and paints, including irreplaceable buildings, statues, and sculptures that are part of our nation's cultural heritage. acid rain can s automotive coatings Acid rain and the dry deposition of acidic particles c to the corrosion of metals (such as bronze) and the deterioration of paint and s (such as marble and limestone). some manufacturers use acid-resistant paints, at an average cost of $ for each new vehicle (or a total of $ million per year for all new cars and trucks sold in the U.S.) CE 326 Principles of Environmental Engineering, Copyright 2007 Tim Ellis, Iowa State University

33 A marble column at the Merchants' Exchange in Philadelphia shows loss of material where the stone is exposed to rain and blackening of the stone surface where the stone is sheltered from rain. CE 326 Principles of Environmental Engineering, Copyright 2007 Tim Ellis, Iowa State University

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35 Affects visibility visibility affected from photochemical smog resulting from SO X,VOC s and NO X Sulfate particles account for percent of the visibility reduction in the eastern part of the United States html CE 326 Principles of Environmental Engineering, Copyright 2007 Tim Ellis, Iowa State University

36 Acid Rain Reductions EPA's Acid Rain Program caps SO 2 emissions from power plants at million tons/yr 1990 Acid Rain Program under the Clean Air Act set goal to achieve reductions of million tons of sulfur dioxide (SO 2 ) and million tons of nitrogen oxides (NO X ). When fully implemented by the year 2010, the public health benefits of the Acid Rain Program are estimated to be valued at $ billion annually, due to decreased m, h admissions, and emergency room visits. for more details see: CE 326 Principles of Environmental Engineering, Copyright 2007 Tim Ellis, Iowa State University

37 Ozone Depletion % of the planet's ozone is in the ozone layer in the statosphere (10-50 kilometers above the Earth's surface) Stratospheric ozone is a naturally-occurring g that filters the sun's ultraviolet (UV) radiation d ozone layer allows more radiation to reach the Earth's surface. CE 326 Principles of Environmental Engineering, Copyright 2007 Tim Ellis, Iowa State University

38 Ozone Depletion overexposure to UV rays can lead to s cancer, c, and weakened i systems. Increased UV can also lead to reduced d c yield and disruptions in the m food chain. ozone destruction occurs when the release of c (CFCs) and other ozonedepleting substances (ODS), widely used as refrigerants, insulating foams, and solvents. CFCs are heavier than air, can take as long as years to reach the stratosphere Measurements of CFCs in the stratosphere are made from b, aircraft, and satellites. CE 326 Principles of Environmental Engineering, Copyright 2007 Tim Ellis, Iowa State University

39 Ozone Depletion When CFCs reach the stratosphere, the u radiation from the sun causes them to break apart and release c atoms which react with ozone, starting chemical cycles of ozone destruction that deplete the ozone layer. One chlorine atom can break apart more than ozone molecules. l Other chemicals that damage the ozone layer include: m bromide (used as a pesticide) h (used in fire extinguishers), and m chloroform (used as a solvent in industrial processes). CE 326 Principles of Environmental Engineering, Copyright 2007 Tim Ellis, Iowa State University

40 Ozone Depletion As methyl bromide and halons are broken apart, they release bromine atoms, which are 40 times more destructive to ozone molecules than chlorine atoms. Halon-1301 has times depleting potential as CFC-11 total chlorine is d, while bromine from industrial halons is increasing volcanoes and oceans release large amounts of chlorine, the chlorine from these sources is easily dissolved in water and washes out of the atmosphere in rain. CFCs are not broken down in the lower atmosphere and do not dissolve in water. CE 326 Principles of Environmental Engineering, Copyright 2007 Tim Ellis, Iowa State University7

41 Ozone Depletion the increase in stratospheric c since 1985 matches the amount released from CFCs and other ozone-depleting substances produced and released by human activities. In 1978, the use of CFC p in spray cans was banned in the U.S. In the 1980s, the Antarctic "o hole" appeared and an international science assessment more strongly linked the release of CFCs and ozone depletion. CE 326 Principles of Environmental Engineering, Copyright 2007 Tim Ellis, Iowa State University7

42 Ozone Depletion 1987, the Montreal Protocol was signed and the signatory nations committed themselves to a r in the use of CFCs and other ozone-depleting substances. Since that time, the treaty has been amended to ban CFC production after 1995 in the d countries, and later in developing countries.

43 Ozone Depletion Today, over 160 countries have signed the treaty. Since January 1, 1996, only r and stockpiled CFCs are available for use in developed countries like the US. This production phaseout is possible because of efforts to ensure that there will be s chemicals for all CFC uses. but provided that we stop producing ozone-depleting substances, n ozone production reactions should return the ozone layer to normal levels by about 2050.