Toxicology and Air Pollution Bock – Flashcards

A risk is a measure of your likelihood of suffering harm from a hazard. 1. Such a hazard may cause injury, disease, economic loss, or environmental damage. 2. Risk assessment is projected as a probability: a mathematical statement about how likely it is that harm will result from a hazard. It gives the estimate of an event's actually happening. 3. Risk management involves deciding whether or how to reduce a particular risk to a certain level and at what cost.

1. One major hazard is a cultural hazard, such an unsafe working conditions, smoking, poor diet, drugs, unsafe sex, poverty, criminal assault, etc. 2. Chemical hazards are harmful chemicals in the air, water, soil, and food. 3. Physical hazards include radioactivity, fire, earthquake, floods, etc. 4. Biological hazards come from pathogens, pollen, other allergens, and animals such as bees and poisonous snakes.

1.Toxicity measures how harmful a substance is in causing injury, illness, or death to a living organism. Several factors to consider are: a.dose, the amount of a substance a person is exposed to, b.frequency of exposure, c.age and size of the individual exposed, d.the health of the body's detoxification system, and e.the genetic makeup of the individual, which is also important for determining sensitivity to a toxin.

a.Solubility. Water-soluble toxins can move throughout the environment. Oil- or fat-soluble toxins (generally organic compounds) can penetrate the membranes surrounding an organism's cells and accumulate in the body. b.Persistence of a substance is also important. Some substances resist breakdown and remain in the environment a long time and can have long-lasting harmful effects. c.Bioaccumulation is a third factor. Molecules are absorbed and stored in the body at higher than normal levels. d.Biomagnification is where toxins accumulate at greater levels as they are moved up from one trophic level to the next higher one. e.Chemical interactions can decrease or multiply the harmful effects of a toxin. An antagonistic interaction reduces the harmful effect, while a synergistic interaction multiplies the harmful effects.

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1. The critical question is: How much exposure to a particular toxic chemical causes a harmful response? It is different for each individual.

a. It can break down, dilute, or excrete small amounts of most toxins to keep them from reaching harmful levels. b. Certain enzymes can sometimes repair damage to DNA and protein molecules. c. Cells in certain parts of the body (skin, gastrointestinal tract, lungs, and blood vessels) can reproduce fast enough to replace damaged cells.

1. Some scientists think that trace levels of most chemicals are not harmful. 2. Other scientists feel we need to evaluate the long-term harm caused by exposure to low doses of many new synthetic chemicals. 3. Natural chemicals in the environment are sometimes thought to be safe, but this is a false impression since nature has an arsenal of harmful chemicals for defense also.

1. A widely used method for estimating the toxicity of a chemical is to determine its lethal dose. A median lethal dose (LD50) for a chemical is the amount in one dose that kills 50% of the test animals within a 14-day period. 2. Chemicals vary widely in their toxicity. The five top toxic substances named by the EPA in 2004 are arsenic, lead, mercury, vinyl chloride, and polychlorinated biphenyls, in that order.

1. Case reports compare the health of a group of people exposed to a chemical to the health of a similar group that was not exposed. This comparison is used to estimate toxicity. 2. These reports are generally not reliable in determining toxicity. 3. The reports can provide clues about environmental hazards.

a. The study can be limited as to usefulness because too few people have been exposed to high enough levels of a substance for there to be statistically significant differences. b. Another limitation is that it is difficult to conclusively link an observed effect with exposure to a specific chemical because people are exposed to many different toxic agents throughout their lives. c. These studies cannot evaluate hazards from new technologies/chemicals to which people have not been exposed.

1. A population of live laboratory animals is exposed to measured doses of a substance under controlled conditions. 2. Such a study takes from 2-5 years. 3. Methods other than animal testing include: computer simulations, using tissue cultures of cells and bacteria and chicken membranes, as well as measuring changes in the electrical properties of individual animal cells.

a. The non-threshold dose-response model states that any dosage of a toxic chemical/ionizing radiation causes harm that increases with dosage. b. The threshold dose-response model states that a threshold dosage must be reached before any detectable harmful effects occur. This may be because the body can repair damage caused by low dosages of some substances.

a. Extrapolation of data from test animals to humans is controversial. b. There is controversy, also, on assuming that an increased dosage always causes great harm. c. The toxicity of a single substance is difficult to estimate, especially with the varying chemical exposures on individuals. d. There are debates over chemical interactions and their effect on toxicity.

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1. The phenomenon of beneficial effects from small doses of toxins is called hormesis. 2. Edward Calabrese at the University of Massachusetts has examined the literature and feels that this hypothesis might have some merit.

1. A toxic chemical can cause temporary or permanent harm or death to humans or animals. 2. A hazardous chemical can harm because it is flammable or explosive or because it irritates or damages skin or lungs or induces allergic reactions.

a. Mutagens are chemicals or ionizing radiation that cause or increase the frequency of random mutations in the DNA molecules. It is generally accepted that there is no safe threshold for exposure to harmful mutagens. b. Teratogens are chemicals that cause harm or birth defects to a fetus or embryo. Alcohol and thalidomide are examples of teratogens. c. Carcinogens are chemicals or ionizing radiation that cause or promote cancer.

1. The immune system consists of specialized cells and tissues that protect the body against disease and harmful substances. It forms antibodies that make invading agents harmless. 2. Neurotoxins are types of poisons that attack the nervous system that consists of the brain, spinal cord, and peripheral nerves. 3. The endocrine system is a complex glandular system that releases small amounts of hormones into the bloodstream of vertebrates. Low levels of these chemicals turn on and off bodily systems controlling sexual reproduction, growth, development, learning ability, and behavior.

1. Human-made chemicals know as hormonally active agents (HAAs) can act as hormone/endocrine disrupters. 2. These HAAS may disrupt human immune functions and may have adverse reproductive and developmental effects on vertebrates exposed to them. We do not know if they pose a threat to human health, even at low levels in the environment.

1. The toxicity of most chemicals has not been determined. 2. Only 2% of the chemicals in commercial use have been adequately tested to determine whether they are carcinogens, teratogens, or mutagens. 3. 99.5% of commercially used chemicals in the U. S. are not regulated. a. Most chemicals are considered innocent until shown to be guilty. b. There are also not enough funds, personnel, facilities, and test animals available to provide information for all the chemicals we encounter in our daily lives.

1. Two major changes in the way we evaluate risks would be: a. New chemicals and technologies would be assumed harmful until studies show otherwise. b. Existing chemicals and technologies that appear to have a strong chance of causing harm would be removed from the market until their safety is established. 2. The European Union agreed to a global treaty that would ban or phase out use of 12 of the most notorious persistent organic pollutants. This treaty went into effect in 2004. 3. There is controversy about whether this precautionary principle will stifle or promote research and new technology.

1. Non-transmissible disease tend to develop slowly, have multiple causes, are not caused by living organisms, and do not spread from one person to another. Examples are cancer, diabetes, asthma, malnutrition, and blood vessel disorders. 2. Transmissible disease is caused by a living organism and can spread from on to another. Infectious agents/pathogens are spread in air, water, food, and body fluids and by some insects and vectors. 3. The World Health Organization stated that about 30% of all deaths per year are caused by non-transmissible cardiovascular disease, 26% by transmissible infectious disease, and 12% by non-transmissible cancers. 4. An epidemiological transition usually occurs as a country industrializes. Incidence of infectious disease-caused deaths decreases and chronic diseases of adulthood increase. 5. Mixed news is that death from infectious diseases has decreased, but many bacteria have developed immunity to widely used antibiotics.

1. The bacteria can transfer this resistance to nonresistant bacteria. 2. Human travel and trade spread bacteria rapidly across the globe. 3. Doctors overuse antibiotics. 4. The availability of antibiotics in many countries without a prescription makes them abundant. 5. Resistance to antibiotics has increased because of antibiotics being used in livestock and dairy animals to control disease and promote growth. 6. Overuse of pesticides increases pesticide resistant insects and other carriers of bacterial diseases. 7. Public pressure has caused some phasing out of antibiotic use in cattle. 8. We should focus on learning how to weaken the effects of infectious microbes by making them less virulent rather than trying to wipe them out.

1. Tuberculosis is a silent global epidemic, since many people do not know that they have been infected. 2. Several factors account for the recent increase in TB: a. lack of screening, especially in developing countries, b. increased population growth and urbanization means greater contact between people, c. there are genetically resistant strains of TB to almost all effective antibiotics, and d. the spread of AIDS weakens the immune system and allows the TB bacteria to multiply 3. There must be early detection and treatment of people with active TB to slow the spread of the disease.

1. The biggest killer is HIV, transmitted in a variety of ways. Globally, it infects at least 5 million people a year. The resulting complications from AIDS kill about 3 million people a year. 2. Influenza virus is the second biggest killer from viral infection. It kills about 1 million people a year. 3. The third largest killer is the hepatitis B virus (HBV) that damages liver and kills about 1 million people a year. It is transmitted by the same methods as HIV. 4. Health officials are concerned about the emergence of Ebola, West Nile virus, and severe acute respiratory syndrome (SARS) in recent years. 5. Vaccines are the best weapons against viruses. They stimulate the body's immune system to produce antibodies to ward off viral infections.

1. The WHO stated that by the beginning of 2004 there were 43 million people worldwide who were infected with HIV. 2. Each day about 14,000 more people are infected with HIV. 3. Within 7-10 years at least half of those with HIV develop AIDS, with most of them in the 15-24 age group and most in developing countries, especially in Africa south of the Sahara Desert. 4. There is no vaccine for HIV and no cure for AIDS. 5. Life expectancy in sub-Saharan Africa has dropped from 62 years to 47 years. 6. The death toll to AIDS will reach 5 million a year by 2020, the same as losing one of every five people in the U.S. 7. The WHO stated that five major strategies are needed to slow the spread of AIDS. a. Shrink the number of people capable of infecting others by quickly reducing the number of new infections below the number of deaths. b. Concentrate on the groups that are most likely to spread the disease such as truck drivers, sex workers, and soldiers. c. Provide free HIV testing. d. Use mass advertising and education for adults and school children. e. Provide free or low-cost drugs to slow the progress of the disease.

1. It is caused by four species of protozoan parasites in the genus Plasmodium. 2. The parasite circulates from mosquito to human and back to mosquito. 3. The cycle repeats until immunity develops or treatment is given or the victim dies. 4. During the 1950s and 1960s, malaria was curtailed by spraying and draining swamps and marshes, but most species of mosquito have become genetically resistant to insecticides and anti-malarial drugs. 5. In 2002, scientists announced that they had broken the genetic code for both the mosquito and the parasite that causes malaria. This could eventually lead to control of this organism. 6. Currently, prevention is the best method to control its spread. Methods include fixing leaking water pipes, using mosquito netting, cultivating fish that feed on mosquito larvae, planting trees that soak up water in marshy areas, and using zinc and vitamin A supplements to boost resistance in children.

1. Death rates from infectious diseases in developing countries are unacceptably high. 2. Only about 10% of global medical research and development money is spent on infectious diseases in developing countries. 3. Research on antibiotics and vaccines has decreased because they are difficult and costly to develop and produce lower profits compared to medicines used for chronic diseases. 4. About one-third of the world's people lack access to clean drinking water and sanitation facilities 5. Children under five make up about 10% of the world's population, but account for 40% of global illness. 6. Global death rate dropped by about two-thirds between 1970 and 2000. The number of children immunized between 1971 and 2000 went from 10% to 84% and saved an estimated 10 million lives a year. 7. To reduce the incidence of infectious disease, we now use oral rehydration therapy to replace water in victims of diarrheal diseases.

1. Biological warfare agents are easy and cheap to produce in a small area. 2. Recombinant DNA techniques are used to produce more virulent, faster acting organisms, and they are resistant to antibiotics. 3. Many people now have the knowledge to make recombinant organisms, and some of these people live in poverty. 4. Biological weapons can be carried in small vials that are not detectable by any of the standard methods. 5. Scientists are experimenting with bees, beetles, moths, and crickets to see whether they can be used as environmental monitors of chemical and biological agents. 6. DNA detectors are also being developed to test for biological agents.

1. Risk assessment involves identifying hazards and evaluating their associated risks. 2. In terms of premature deaths per year and reduced life span, the greatest risk by far is poverty. 3. Reducing poverty would improve human rights, provide more people with income to stimulate economic development, and reduce environmental degradation and the threat of terrorism. 4. Avoidance of cultural hazards also improves longevity of life.

1. System reliability (%) = Technology reliability x Human reliability. 2. One way to make a system more foolproof or failsafe is to move more of the potentially fallible elements from the human side to the technical side. 3. Chance events can still cause problems.

1. The atmosphere is a thin layer of gases divided into several spherical sublayers. 2. Density and atmospheric pressure vary throughout the atmosphere due to gravitational forces that pull the gas molecules toward the earth's surface. Air at sea level has a higher density than air at the top of a mountain. 3. Atmospheric pressure is a measure of the mass per unit of air. It decreases with altitude.

1. This layer extends about 11 miles above sea level at the equator and about 5 miles above the poles. 2. About 99% of the volume of air is made up of nitrogen (78%) and oxygen (21%) with the rest consisting of water vapor, argon, carbon dioxide, and traces of several other gases. 3. This layer is also responsible for short-term weather and long-term climate

1. The concentration of ozone in this layer is much higher than in the troposphere. 2. Ozone is produced when oxygen molecules interact with ultraviolet radiation (3 O2 + UV 2 O3). This "global sunscreen" keeps about 95% of the sun's harmful UV radiation from reaching the earth's surface. 3. This ozone layer protects us from sunburn, cataracts, cancer of skin and eye, and damage to our immune system. 4. There is evidence of a decrease in "good" ozone in the stratosphere and an increase in "bad" ozone in the troposphere.

1. Chemicals in the atmosphere in concentrations high enough to affect climate, materials, and health are what constitute air pollution. 2. Natural sources of air pollution such as dust particles, organic chemicals released by plant decay, forest fires, etc. rarely reach harmful levels. 3. Increased use of fossil fuels has greatly increased the amount of air pollution, especially in urban areas where people, cars, and industry are concentrated. 4. Outdoor air pollutants are classified into two categories: primary pollutants that enter directly into the troposphere (soot, carbon monoxide) and secondary pollutants that may form when primary pollutants interact with one another or with the air to form new pollutants. 5. Cities generally have higher pollution levels than rural areas. Winds can carry these pollutants away from their source to other areas. 6. Indoor air pollutants come from infiltration of outside air and chemicals used or produced inside buildings. 7. Air pollution is classified as a high-risk human health problem. 8. Most people exposed to poor air live in developing countries. 9. Six conventional air pollutants have maximum standards of allowable concentrations set by governments of developed countries

1. There are three reasons for classifying CO2 as an air pollutant. a. In high concentrations any chemical can become a pollutant b. CO2 concentration in the troposphere has increased due to fossil fuel burning and clearing trees that absorb CO2. c. The troposphere is warming. 2. Global warming can also change global climate patterns.

1. A photochemical reaction is any chemical reaction activated by light. 2. Photochemical smog contains more than 100 primary and secondary pollutants. 3. Nitrogen dioxide found in photochemical smog is a yellow-brown gas with a noxious odor and causes a brownish haze to form. 4. Some NO2 reacts with hydrocarbons to produce a mixture of ozone, nitric acid, aldehydes, peroxyacyl nitrates (PANs), and other pollutants. 5. These substances are photochemical oxidants and can irritate the respiratory tract and damage crops and trees. 6. Photochemical smog is more common in cities in warm, dry, sunny areas.

1. Some tree and other plant species emit volatile organic compounds that are components of photochemical smog. 2. Unless forests are close to urban areas with large sources of NOx they do not make a significant contribution to pollution.

1. When coal is burned, it is converted to carbon dioxide, carbon monoxide, and unburned carbon particles (soot). 2. Coal and oil also contain sulfur that is then converted to sulfur dioxide. 3. Reactions with water vapor changes sulfur dioxide to sulfuric acid in several steps. These droplets can then react with ammonia in the atmosphere to form ammonium sulfate. These various components give the air a gray color. 4. Most countries have adopted pollution controls, but several countries with industrialized urban areas have serious smog problems. 5. China has a serious gray-smog problem in many areas, and many people die prematurely from this.

1. Three natural factors help reduce outdoor air pollution: rain and snow, salty sea spray, and winds. Each of these factors helps remove pollutants, but they are then deposited elsewhere. 2. Four factors can increase outdoor air pollution: urban buildings, hills and mountains, high temperatures, and the grasshopper effect where volatile compounds are carried from tropical or temperate areas to the poles.

1. Turbulence, caused by the mixing of warm and cold air, disperses air pollutants. 2. A temperature inversion, where a layer of warm air sits over a layer of cold air, prevents the mixing, and dense, colder air becomes stagnant and accumulates more pollutants. 3. Two areas are particularly susceptible to inversions: a. a city located in a valley surrounded by mountains that experiences cloudy, cold weather part of the year and b. a sunny climate with light winds and mountains on three sides and several million people and vehicles (Los Angeles basin).

1. The rapid industrialization of China and India is repeating what had existed in Europe and the U.S. as part of the industrial revolution during the 19th and early 20th century. 2. Solar energy reaching the earth is reduced 2-15% in some areas. 3. Rice crops may be reduced 3-10% by this in India's winter harvests. 4. Crops, trees, and life in lakes are being damaged. 5. This may also be an important contributor to premature deaths from respiratory diseases. 6. This huge brown cloud also seems to be causing changes in regional climate, warming some areas and cooling others. There are also shifting rainfall patterns. 7. The good news is that this problem can be greatly reduced by setting standards for coal-burning industries, changing to cleaner burning gas, and using catalytic converters on cars. China has begun to do this, as has Delhi, India.

1. Tall smokestacks reduce local pollution, but can increase regional pollution. 2. Acidic particles remain in the atmosphere for 2-14 days, depending on the prevailing winds, precipitation, and other weather patterns. 3. The acidic substances return to the earth in one of two forms: a. wet deposition as acidic rain, snow, fog, and cold vapor with a pH less than 5.6 and b. dry deposition as acidic particles. 4. Acid deposition is a problem in areas downwind from coal-burning facilities and urban areas. 5. Some areas have basic compounds in the soil that act to buffer or neutralize some acidic deposits. 6. Many acid-producing chemicals generated in one country end up in other countries due to prevailing winds.

1. Large amounts of money are spent each year to clean and repair monuments and statues damaged by acid deposition. 2. Acid deposition also decreases atmospheric visibility. 3. Acidified lakes have fish kill, and aluminum ions are released into the water by the lower pH (4.5 or less). 4. Many lakes in northern Europe and the eastern U.S. have few, if any, fish due to decreased pH.

1. Effects of acid deposition on plants is caused partly by chemical interaction in the soils. 2. There may be an initial growth stimulus from added nitrogen and sulfur, but continued deposition leaches essential magnesium and calcium salts from the soil and lowers plant productivity. 3. Herbivores that eat these plants can also develop calcium deficiencies. 4. Synergistic effects may occur when the plants are exposed to several pollutants simultaneously. 5. Acid can also dissolve aluminum, cadmium, and mercury ions from the soil. These ions are toxic to plants and animals. 6. Acid-loving mosses may be stimulated to grow and harm trees by holding quantities of water and killing mycorrhizal fungi needed by the trees. 7. Weakened trees are more susceptible to diseases. 8. The mountaintop trees are those that are most harmed by acidic rain because they are also growing in thin soils.

1. The 1990 amendments to the Clean Air Act have lead to significant reductions in SO2 and NOx emissions from coal-fired power and industrial plants. 2. Acid deposition has accelerated leaching of ions such as calcium and magnesium from soils in some areas, which could lead to a decrease in tree growth. 3. Acid deposition has also increased concentrations of toxic forms of aluminum in some soil and in lakes and streams. 4. It is predicted that an additional 80% reduction in SO2 emissions would be needed to allow northeastern streams and lakes to recover from the effects of acid deposition.

1. The best approaches are those that reduce or eliminate emissions of SO2, NOx, and particulates. 2. Use of low sulfur coal is both good and bad; it lowers the amount of SO2 released, but because more must be burned to generate the same amount of electricity, it emits more mercury, CO2, and radioactive particles. 3. Controlling acid deposition is a politically controversial issue. 4. Inclusion of environmental and health costs to the current costs of coal would give a more realistic picture. 5. Approaches to neutralize acid lakes include adding limestone or lime to the water or soil or adding a small amount of phosphate fertilizer; this approach is being evaluated.

1. EPA studies have shown that: a. levels of 11 common pollutants are 2-5 times greater inside homes and commercial buildings than outside. b. inside cars in traffic-clogged areas, the pollution may be 18 times higher than outside. c. health risks are magnified because people usually spend 70-98% of their time indoors or in vehicles. 2. Sick-building syndrome has been linked to various air pollutants, and new buildings are apt to be more prone to this than old buildings due to less air exchange. 3. The EPA lists the four most dangerous indoor air pollutants in developed countries as cigarette smoke, formaldehyde, radioactive radon-222 gas, and very small fine and ultrafine particles. 4. In developing countries, as many as 2.8 million people die prematurely each year from breathing elevated levels of indoor smoke and particulates. B. Formaldehyde is the chemical that causes most people in developed countries difficulty. It is used to manufacture common household materials. C. Radon-222 gas is found in some soils and rocks and can seep into some homes and increase the risk of lung cancer. 1. Radon is produced by the radioactive decay of uranium-238. 2. Radon gas tends to be pulled into homes because of the slightly lower atmospheric pressure inside most homes. 3. Radon is thought to be the second leading cause of lung cancer deaths each year in the U.S. 4. The EPA and the Surgeon General's Office recommended that everyone living in a detached home, a townhouse, or the first three levels of an apartment building test for radon. 5. Remedies include sealing cracks in foundation and walls, increasing ventilation, and using a fan for cross ventilation.

1. Hairs in the nose filter out large particles. Sticky mucus lines the respiratory trap to capture smaller particles and some dissolved gases. 2. Sneezing and coughing expel contaminated air and mucus. 3. Prolonged or acute exposure to air pollutants can overload or break down the natural defenses. 4. Several respiratory diseases can develop such as asthma, lung cancer, chronic bronchitis, and emphysema. 5. People with respiratory diseases, older adults, infants, pregnant women, and people with heart disease are especially vulnerable to air pollution

1. Air pollution deaths in the U.S. range from 150,000 to 350,000 people per year. 2. A large diesel-powered bulldozer produces as much air pollution as 26 cars. 3. The EPA proposed emission standards for diesel-powered vehicles that go into effect in 2007 with full compliance by 2012. It is thought that this will reduce diesel-fuel emissions by 90%.

1. The U.S. Congress passed Clean Air Acts in 1970, 1977, and 1990. 2. National air quality standards (NAAQS) were established for six outdoor criteria pollutants. 3. Two limits were established: a primary standard is set to protect human health and a secondary standard is set to prevent environmental and property damage. 4. The EPA has established national emission standards for 188 hazardous air pollutants (HAPs) that may cause serious health and ecological effects. These include neurotoxins, carcinogens, mutagens, teratogens, and others. 5. The good news is that the six criteria air pollutants decreased 48% between 1983 and 2002 even with increased energy consumption, miles traveled, and population. 6. Between 1983 and 2002, emissions from the six major air pollutants decreased: 93% for lead, 41% for carbon monoxide, 40% for volatile organic compounds, 34% for suspended particulate matter, 33% for sulfur dioxide, and 15% for NOx. 7. Release of two HAPs—mercury and dioxins has increased in recent years. These are toxic at very low levels. The EPA estimates that about 100 million Americans live in areas where the risk of cancer from HAPs is 10 times higher than the accepted standard. 8. Smog levels did not drop any between 1993 and 2003 after dropping in the 1980s.

1. U.S. citizens insisted that laws be passed and enforced to improve air quality, and the country was affluent enough to afford the controls and improvements. 2. One deficiency in the Clean Air Act is that we rely more on cleanup rather than prevention. 3. Another deficiency is that Congress has not increased fuel-efficiency standards for cars, etc. 4. Inefficient two-cycle engines have been inadequately regulated regarding emissions. 5. Oceangoing ships have little or no air pollution regulations. 6. The Clean Air Acts have not done much to reduce greenhouse gas emissions. 7. There has been little done to deal seriously with indoor air pollution that is considered the most serious problem in terms of poorer health, premature deaths, and economic losses from lost work time. 8. Better enforcement of these acts is also needed. Company executives claim that improvements would cost too much, but these estimates are often too high and implementation has helped to increase economic growth and create jobs.

1. The Clean Air Act of 1990 allows an emissions trading policy that permits companies to buy and sell SO2 pollution rights. 2. This cap-and-trade approach may be an improvement over command-and-control as long as it reduces SO2 emissions. The cap would gradually be lowered. 3. These pollution credits may be purchased by anyone and then not used if they so desire. 4. This method allows "hot spots" to continue to exist. Spot monitoring to check for emissions should be done. 5. Between 1980 and 2002, this scheme reduced SO2 emissions by 40% in the U.S. 6. Emissions trading has been expanded to include NOx, particulate emissions, and volatile organic compounds, and for the combined emissions of SO2, NOx, and mercury from coal-burning power plants. 7. The Clear Skies Initiative of 2001 has been criticized as a way for big polluters to continue polluting. 8. This plan is not a good one for reducing toxic mercury in the environment. 9. In 2002, the EPA reported that the largest and oldest cap-and-trade program produced less emissions reductions than projected or that could be expected. There were accounting abuses.

1. Cleanup has emphasized output approaches that add equipment to remove materials. 2. Pollution can also be reduced at the input stage with such technologies as fluidized-bed combustion and coal gasification.

1. A 1977 rule in the Clean Air Act (New Source Review) requires older plants to upgrade pollution control equipment when they expand or modernize the facilities. 2. This has been circumvented by calling these expansions maintenance. 3. In 2002, the Bush administration eased the New Resource Review restrictions for older facilities. 4. In 2003, the National Academy of Public Administration advised Congress to give the dirtiest coal-fired power and industrial plants a 10-year deadline to install the most modern pollution controls or shut down.

1. Get older, more polluting vehicles off the road. 2. In 2003, a new process removed pollutants from fuels of vehicles. It is a class of chemicals called zeolites and uses an adsorption process that is more efficient than catalytic converters. 3. Hybrid-electric vehicles and zero-emission vehicles should reduce emissions over the next 10-20 years. 4. Developing countries are increasing their air pollution with more vehicles on the road that are over 10 years old and are without pollution controls.

1. Fine particles (less than 10 microns) and ultrafine particles (less than 2.5 microns) are generally not captured by most air pollution control equipment. 2. These particles penetrate the natural defenses of the respiratory system. 3. These particles are estimated to kill 65,000-200,000 Americans per year. This number is even higher in developing countries (300,000-700,000). 4. Costs to implement stricter standards are estimated at $7 billion/year with health and other benefits of $120 billion/year.

1. Figure 20-20 suggests several ways to reduce indoor air pollution. 2. In developing countries, indoor air pollution can be reduced by use of clay or metal stoves and venting to the outside, and by use of solar cookers in sunny areas. This would also reduce deforestation.

1. At present, there is an output approach to controlling pollution. 2. We need to shift focus to preventing air pollution. 3. Figure 20-21 shows ways to prevent air pollution over the next 30-40 years. 4. Figure 20-22 lists ways to reduce your exposure to indoor air pollution.