Chapter 10 (Air Pollution) Lecture Outline

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Introduction Clean air is something we take for granted when we have it, but once a regions air pollution becomes severe, removing those pollutants presents an enormous challenge. Pollution comes in many forms. Smoke, haze, dust, odors, corrosive gases, noise, and toxic compounds are among our most widespread pollutants. Some pollutants, such as sulfur dioxide, irritate our eyes and lungs; fine particulates penetrate deep into our lungs; airborne metals enter our blood stream when we breathe them, then damage nerves and brain function. Worldwide, these air pollution emissions add up to about 2 billion metric tons per year. Sometimes the health and environmental costs of air pollution are shocking, as in London in 1952. But most of the time the costs are more subtle. Chronic illness, resulting from low-level, ongoing exposure is likely to cause more deaths and higher health-care costs than serious but infrequent deadly smog events. The Organization for Economic Cooperation and Development has projected that by 2050, chronic exposure to ground-level ozone, fine particulate matter, sulfur dioxide, and other pollutants will cause 3.6 million premature deaths every year. Go to the next slide for six important learning outcomes. Clean air is something we take for granted when we have it, but once a regions air pollution becomes severe, removing those pollutants presents an enormous challenge. Pollution comes in many forms. Smoke, haze, dust, odors, corrosive gases, noise, and toxic compounds are among our most widespread pollutants. Some pollutants, such as sulfur dioxide, irritate our eyes and lungs; fine particulates penetrate deep into our lungs; airborne metals enter our blood stream when we breathe them, then damage nerves and brain function. Worldwide, these air pollution emissions add up to about 2 billion metric tons per year. Sometimes the health and environmental costs of air pollution are shocking, as in London in 1952. But most of the time the costs are more subtle. Chronic illness, resulting from low-level, ongoing exposure is likely to cause more deaths and higher health-care costs than serious but infrequent deadly smog events. The Organization for Economic Cooperation and Development has projected that by 2050, chronic exposure to ground-level ozone, fine particulate matter, sulfur dioxide, and other pollutants will cause 3.6 million premature deaths every year. Go to the next slide for six important learning outcomes. Enjoy the air pollution chapter. 10-2

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<p>Chapter 10 (Air Pollution) Lecture Outline<br> 2014 by McGraw-Hill Education. This is proprietary material solely for authorized instructor use. Not authorized for sale or distribution in any manner.This documentmay not be copied, scanned, duplicated, forwarded, distributed, or posted on a website, in whole or part. Introduction Clean air is something we take for granted when we have it, but once a regions air pollution becomes severe, removing those pollutants presents an enormous challenge. Pollution comes in many forms.Smoke, haze, dust, odors, corrosive gases, noise, and toxic compounds are among our most widespread pollutants. Some pollutants, such as sulfur dioxide, irritate our eyes and lungs; fine particulates penetrate deep into our lungs; airborne metals enter our blood stream when we breathe them, then damage nerves and brain function.Worldwide, these air pollution emissions add up to about 2 billion metric tons per year. Sometimes the health and environmental costs of air pollution are shocking, as in London in But most of the time the costs are more subtle. Chronic illness, resulting from low-level, ongoing exposure is likely to cause more deaths and higher health-care costs than serious but infrequent deadly smog events. The Organization for Economic Cooperation and Development has projected that by 2050, chronic exposure to ground-level ozone, fine particulate matter, sulfur dioxide, and other pollutants will cause 3.6 million premature deaths every year. Go to the next slide for six important learning outcomes. Clean air is something we take for granted when we have it, but once a regions air pollution becomes severe, removing those pollutants presents an enormous challenge. Pollution comes in many forms.Smoke, haze, dust, odors, corrosive gases, noise, and toxic compounds are among our most widespread pollutants. Some pollutants, such as sulfur dioxide, irritate our eyes and lungs; fine particulates penetrate deep into our lungs; airborne metals enter our blood stream when we breathe them, then damage nerves and brain function.Worldwide, these air pollution emissions add up to about 2 billion metric tons per year. Sometimes the health and environmental costs of air pollution are shocking, as in London in But most of the time the costs are more subtle. Chronic illness, resulting from low-level, ongoing exposure is likely to cause more deaths and higher health-care costs than serious but infrequent deadly smog events. The Organization for Economic Cooperation and Development has projected that by 2050, chronic exposure to ground-level ozone, fine particulate matter, sulfur dioxide, and other pollutants will cause 3.6 million premature deaths every year. Go to the next slide for six important learning outcomes. Enjoy the air pollution chapter. 10-2 Learning Outcomes After studying this chapter, you should be able to:<br>Generalize the main types and sources of conventional or criteria pollutants. Describe several hazardous air pollutants and their effects. Discover how air pollutants affect the climate and stratospheric ozone. Assess ways that air pollution can affect human health. Identify policies and strategies for reducing air pollution. Discover if world air quality has been getting better or worse. Why? 10-3 International Energy Agency, 2010<br>The next decade is critical. If emissions do not peak by around 2020, the needed 50% reduction by 2050 will become much more costly. In fact, the opportunity may be lost completely. International Energy Agency, 2010 09/22/10 10-4 CASE STUDY: The Great London Smog<br>London was once legendary for its pea-soup fogs. In the days of Charles Dickens and Sherlock Holmes, darkened skies and blackened buildings, saturated with soot from hundreds of thousands of coal-burning fireplaces, were a fact of life. Londoners had been accustomed to filthy air since the beginning of the industrial revolution, but over a period of four days in 1952, days just 60 years ago, they experienced the worst air pollution disaster on record. Smoke, soot, and acidic droplets of fog made the air opaque. Thousands died, thousands more became ill, and our view of air pollution changed forever. In early December 1952, a dense blanket of coal smoke and fog settled on the city. Under normal conditions, winds keep polluted air moving, away from the city and out over the countryside.These winds occur, broadly speaking, because air near the earths surface is usually warmed by the sun-heated ground, while air aloft is cool. Turbulence develops as the warmed air rises and cool air sinks, and the turbulence tends to circulate pollutants away from their sources. But from time to time an inversion develops. As the name implies, an inversion occurs when layers of air are out of order: Still, cold air settles near the ground, trapped by warmer layers above. The killer smog of 1952 came on suddenly, on Friday, December 5. Home heaters and industrial furnaces were working in full force, pumping out smoke on the cold winter day. During the afternoon, visibility plummeted, and traffic came to a halt as drivers were blinded by the smoke and fog. Hundreds of cattle at a cattle market were the first to go. With lungs blackened by soot, they suffocated while standing in their pens. People could cover their faces and go indoors, but the soot soon reached inside buildings, as well. Concerts were cancelled because of blackened air in the halls, and books in the British Museum were tainted with soot. Visibility fell to a foot in some places by the third day of the inversion.The ill and elderly, especially those with lung or heart ailments and heavy smokers, were the next to go. Hospitals filled with victims of bronchitis, pneumonia, lung inflammations, and heart failure. Like the cattle in the market, victims lungs were clogged by smoke and microscopic soot particles, their lips turned blue, and they asphyxiated due to lack of oxygen. Healthy people tried to stay indoors and keep quiet, and children were kept home from schoolso they would not get lost in the dark, as much as because of the air quality.Four days later, a change in the weather brought fresh winds into London, and the inversion dissipated. Studies showed that at least 4,700 deaths were attributable to this air pollution.These alarming death counts caught the attention of politicians and the public alike, and gradually led to changes in expectations and practices. While air quality in cities (and often in the countryside) is frequently worse than we would like, extreme conditions like the killer smog are mainly historical curiosities today. We now have higher expectations for air pollution control, and we no longer find it acceptableat least in principlefor private citizens or industries to emit pollutants that cause illness or death. But things today are nowhere near as bad as they were in London in In this chapter well examine major types and sources of air pollutants. Well also consider policies and technology that help ensure that events like the smog of London doesnt happen in your town. 09/22/10 10-5 10.1 Air Pollution and Health<br>Pollution comes in many forms.Smoke, haze, dust,odors, corrosive gases, noise, and toxic compoundsare among our most widespread pollutants. Pollutants may irritate our eyes and lungs, enter ourblood stream when we breathe them, then damagenerves and brain function. The Organization for Economic Cooperation andDevelopment has projected that by 2050, chronicexposure to pollutants will cause 3.6 millionpremature deaths every year. See the Introduction slide above for additional information. 10-6 6 Pollution Controls are Absent in Many Megacities<br>While air quality is improving in many industrialized countries, newly developing countries have growing pollution problems.Xian, China, often has particulate levels above 300 g/m3. Of the 20 smoggiest cities in the world, 16 are in China. Chinas city dwellers are four to six times more likely than rural people to die of lung cancer. 09/22/10 10-7 The Clean Air Act Regulates Major Pollutants<br>In 1970, The Clean Air Act designated new air quality standards, to be applied equally across the country, for six major pollutants. These six are referred to as conventional or criteria pollutants, and they include sulfur dioxide, nitrogen oxides, carbon monoxide, ozone (and its precursor volatile organic compounds), lead, and particulate matter. Transportation and power plants are the dominant sources of most criteria pollutants. Amendments to The Clean Air Act in 1970 designated new standards, to be applied equally across the country, for six major pollutants: sulfur dioxide, nitrogen oxides, carbon monoxide, ozone (and its precursor volatile organic compounds), lead, and particulate matter. These six are referred to as conventional or criteria pollutants, and they were addressed first because they contributed the largest volume of air quality degradation and also are considered the most serious threat to human health and welfare. Transportation and power plants are the dominant sources of most criteria pollutants (fig. 10.2).National ambient air quality standards (NAAQS) designated allowable levels for these pollutants in the ambient air (the air around us). 10-8 8 Anthropogenic Sources of Criteria Air Pollutants<br>Anthropogenic sources of six of the primary criteria air pollutants in the UnitedStates. 10-9 9 Unconventional Pollutants<br>The EPA also monitors unconventional pollutants,compounds that are produced in less volume thanconventional pollutants, but that are especially toxicor hazardous. Among these are asbestos, benzene, beryllium,mercury, polychlorinated biphenyls (PCBs), and vinylchloride. In 2009, the EPA announced that it would add CO2and other greenhouse gases to its list of regulatedpollutants. This decision remains controversial. In addition to the six conventional pollutants, the Clean Air Act regulates an array of unconventional pollutants, compounds that are produced in less volume than conventional pollutants but that are especially toxic or hazardous, such as asbestos, benzene, mercury, polychlorinated biphenyls (PCBs), and vinyl chloride. Most of these are uncommon in nature or have no natural sources. (fig. 10.3). 10-10 10 How Do We Define Pollution Sources?<br>A point source is a smokestack or some other concentrated pollution origin. Primary pollutants are released in a harmful form. Secondary pollutants become hazardous after reactions in the air. Fugitiveor nonpoint-source emissions are those that do not go through a smokestack. Many pollutants come from a point source, such as a smokestack.Fugitive, or nonpoint-source, emissions are those that do not go through a smokestack. Leaking valves and pipe joints contribute as much as 90 percent of the hydrocarbons and volatile organic chemicals emitted from oil refineries and chemical plants, and increasingly from natural gas wells. Dust, as from mining, agriculture, and building construction and demolition, is also considered fugitive emissions. Primary pollutants are substances that are harmful when released. Secondary pollutants, by contrast, become harmful after they react with other gases or substances in the air. 10-11 11 Fugitive Emissions Many of our most serious pollutants are fugitive emissions from petrochemical facilities such as this one in Baton Rouge, Louisiana. 09/22/10 10-12 Conventional Pollutants are Abundant and Serious<br>Sulfur dioxide (SO2) is a colorless, corrosive gas thatdamages both plants and animals. Once in theatmosphere, it can which reacts with water vaporform sulfuric acid (H2SO4). Nitrogen oxides (NOx) are highly reactive gasesformed when the heat of combustion initiatesreactions between atmospheric nitrogen (N2) andoxygen (O2). The initial product, nitric oxide (NO),oxidizes further in the atmosphere to nitrogendioxide (NO2), a reddish-brown gas that givesphotochemical smog its distinctive color. Sulfur dioxide (SO2) is a colorless, corrosive gas that damages both plants and animals. Once in the atmosphere, it can be further oxidized to sulfur trioxide (SO3), which reacts with water vapor or dissolves in water droplets to form sulfuric acid (H2SO4), a major component of acid rain. Sulfur dioxide and sulfate ionshealth damage. Sulfate particles and droplets also reduce visibility in the United States by as much as 80 percent. Minute droplets of sulfuric acid can penetrate deep into lungs, causing permanent damage, as well as irritating eyes and corroding buildings. In plants, sulfur dioxide destroys chlorophyll, eventually killing tissues. Sulfur dioxide from coal smoke, along with particulate matter, was a principal component of Londons deadly smog event of 1952 (fig. 10.4). Nitrogen oxides (NOx) are highly reactive gases formed when the heat of combustion initiates reactions between atmospheric nitrogen (N2) and oxygen (O2). The initial product, nitric oxide (NO), oxidizes further in the atmosphere to nitrogen dioxide (NO2), a reddish-brown gas that gives photochemical smog its distinctive color. Because these gases convert readily from one form to the other, the general term NOx (with x indicating an unspecified number) is used to describe these gases. Nitrogen oxides combine with water to form nitric acid (HNO3), which is also a major component of acid precipitation (fig. 10.5). Excess nitrogen in water is also causing eutrophication of inland waters and coastal seas. 09/22/10 10-13 Sulfur Dioxide Affects Both People and Plants<br>Sulfur dioxide concentrations and deaths during the London smog of December The EPA standard limit is 0.08 mg/m3 (dashed line, a).The soybean leaf at right (b) was exposed to 2.1 mg/m3 sulfur dioxide for 24 hours. White patches show where chlorophyll has been destroyed 09/22/10 10-14 Conventional Pollutants are Abundant and Serious<br>Carbon monoxide (CO) is a colorless, odorless, buthighly toxic gas produced mainly by incompletecombustion of fuel (coal, oil, charcoal, wood, orgas). CO inhibits respiration in animals by bindingirreversibly to hemoglobin in blood. Ozone (O3) ground level ozone is highly reactiveoxidizing agent that damages eyes, lungs, and planttissues, as well as paint, rubber, and plastics. It is asecondary pollutant, created by chemical reactionsthat are initiated by solar energy. Carbon monoxide (CO) is less common but more dangerous than the principal form of atmospheric carbon, carbon dioxide (CO2). CO is a colorless, odorless, but highly toxic gas produced mainly by incomplete combustion of fuel (coal, oil, charcoal, wood, or gas). CO inhibits respiration in animals by binding irreversibly to hemoglobin in blood. In the United States, two-thirds of the CO emissions are created by internal combustion engines in transportation. Land-clearing fires and cooking fires also are major sources. About 90 percent of the CO in the air is consumed in photochemical reactions that produce ozone. Ozone (O3) is important in the upper atmosphere, where it shields us agai...</p>