CH-17-18 Environmental Hazards and Human Health – Living in the Environment: Principles, Connections, and Solutions : Book Guide

This Document Contains Chapters 17 to 18 SUSTAINING ENVIRONMENTAL QUALITY Chapter 17 Environmental Hazards and Human Health Summary 1. Major types of hazards faced by humans include cultural, physical, chemical, and biological hazards. 2. Toxicology is the scientific field that measures the degree of harm a hazardous agent can cause. Scientists measure toxicity based on dosage, solubility, persistence, bioaccumulation, biomagnification, and chemical interactions. 3. Chemical hazards include agents that are flammable or explosive, damage or irritate lungs or skin, interrupt oxygen uptake, and cause allergies. Chemical hazards are defined by their toxicity, the person’s acute and chronic reactions to it, and its pervasiveness in the environment. 4. The types of disease threatening people in developing countries are primarily infectious diseases of childhood, while those threatening people in developed countries tend to be chronic diseases of adults, such as heart disease, stroke, cancer, and respiratory conditions. 5. Risks can be estimated, managed, and reduced by identifying hazards, evaluating related risks (risk assessment), ranking risks (comparative risk analysis), determining alternative solutions, making decisions about reducing risks (risk management), and informing decision-makers about risk (risk communication). Key Questions and Concepts 17-1 What Major Health Hazards Do We Face? CORE CASE STUDY: A common estrogen mimic is bisphenol A (BPA) which is commonly found in plastics. Evidence suggests that plastic containers release BPA and that it remains in the body for at least 24 hours after being ingested. A. A risk is a measure of your likelihood of suffering harm from a hazard. Hazards may cause injury, disease, economic loss, or environmental damage. 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. Risk management involves deciding whether or how to reduce a particular risk to a certain level and at what cost. B. There are five major types of hazards. 1. Biological hazards come from more than 1400 pathogens (bacteria, viruses, parasites, protozoa, and fungi) that can infect humans. 2. Chemical hazards from harmful chemicals in air, water, soil and food. 3. Physical hazards such as fire, earthquake, volcanic eruption, flood, tornado, and hurricane. 4. Cultural hazards such as smoking, unsafe working conditions, poor diet, drugs, drinking, driving, criminal assault, unsafe sex, and poverty. 5. Lifestyle hazards such as smoking, drinking, etc. 17-2 What Types of Biological Hazards Do We Face? A. Diseases not caused by living organisms do not spread from one person to another, while those caused by living organisms such as bacteria and viruses can spread from person to person. 1. Non-transmissible diseases 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 one to another. Infectious agents/pathogens are spread in air, water, food, body fluids, by some insects, and by vectors. CASE STUDY: Tuberculosis has been spreading rapidly since 1990, striking about 9 million people per year. The reasons for the spread include inadequate screening, the development of new strains of TB and population growth. SCIENCE FOCUS: Rapidly producing infectious bacteria are becoming genetically resistant to widely used antibiotics. The bacteria can transfer this resistance to nonresistant bacteria. Resistance to antibiotics has increased because of antibiotics being over-prescribed, added to household products (e.g., soaps) and used in livestock and dairy animals to control disease and promote growth. B. Viruses evolve quickly and are not affected by antibiotics. The influenza or flu virus is the biggest killer. The second biggest killer is HIV, transmitted in a variety of ways. C. Emergent diseases are newly discovered or have been absent from human populations for at least 20 years. SCIENCE FOCUS: Infectious diseases that are transmitted from wild and domesticated animals to humans include avian flu, SARS, West Nile virus, Hantavirus, and Lyme disease. The clearing and fragmentation of forests has played a major role in exposing humans to new types of infectious disease. Understanding the connections between human activities and ecosystem functioning is a key to preventing or slowing the spread of infectious organisms from wild and domesticated animals to humans. CASE STUDY: The global spread of AIDS is a major health threat. It is transmitted sexually, by exposure to infected blood, and from mother to child. In 2008, about 33 million people worldwide were living with HIV. Since 2006 the number infected has begun to stabilize everywhere except sub-Saharan Africa. CASE STUDY: Malaria kills about 2,700 people per day and has probably killed more people than all of the wars ever fought. Malaria is caused by a parasite that is spread by the bites of certain mosquitoes. It is caused by four species of protozoan parasites in the genus Plasmodium and the parasite circulates from mosquito to human and back to mosquito. D. There are a number of ways to reduce the incidence of infectious diseases if the world is willing to provide the necessary funds and assistance. Global death rate dropped by about 2/3rds between 1970 and 2000. The number of children immunized between 1971 and 2006 went from 10% to 90% and saved an estimated 10 million lives a year. Only about 10% of global medical research and development money is spent on preventing infectious diseases in developing countries, even though more people worldwide suffer and die from these diseases than all other diseases combined. 17-3 What Types of Chemical Hazards Do We Face? A. A toxic chemical can cause temporary or permanent harm or death to humans or animals. B. There are three major types of potentially toxic agents. 1. 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. 2. Teratogens are chemicals that cause harm or birth defects to a fetus or embryo. Alcohol and thalidomide are examples of teratogens. 3. Carcinogens are chemicals or ionizing radiation that cause or promote cancer. CASE STUDY: PCBs are a class of 200+ chlorine containing compounds that are very stable and non-flammable. Congress banned domestic production in 1977 after they were shown to cause cancer. For decades they were released into air, water and soil. As a result, they are now found almost everywhere. C. Long-term exposure to some chemicals at low doses may disrupt the body’s immune, nervous, and endocrine systems. 1. Some chemicals weaken the human immune system. 2. Some chemicals are neurotoxins, causing harm to the nervous system. SCIENCE FOCUS: Exposure to mercury can damage the human nervous system, kidneys and lungs. 1/3 of the mercury in the atmosphere is derived from natural sources. The remainder comes from coal-burning facilities and waste incinerators. People are exposed to mercury by breathing it in, eating contaminated fish, and consuming high fructose corn syrup. D. Certain molecules can disrupt the endocrine system. These are called hormonally active agents (HAAs). 1. Hormone blockers prevent natural hormones from attaching to their receptors. 17-4 How Can We Evaluate Chemical Hazards? A. Factors determining the harm caused by exposure to a chemical include the amount of exposure (dose), the frequency of exposure, the person who is exposed, the effectiveness of the body’s detoxification systems, and the exposed person’s genetic makeup. Other factors can affect the harm caused by a substance including solubility, persistence, bioaccumulation, biomagnification, and chemical interactions. 1. Acute effects are immediate. 2. Chronic effects are permanent. CASE STUDY: Children can be particularly sensitive to toxic chemicals because they breathe more air and consume more water and food per unit body weight, they put things in their mouths, and their immune systems are less well-developed. B. Toxicity is usually measured using laboratory animals, but increasingly with computer simulations or cell cultures. C. There are two types of dose-response curve. With the non-threshold dose-response model, any dosage causes harm that increases with the dosage. With the threshold dose-response model, a certain level must be reached before harmful effects occur. D. Other ways to estimate the harmful effects of chemicals are case studies and epidemiological studies. E. It is difficult to assess the risk associated with trace amounts of chemicals found in our environment. F. Only 10% of 100,000 registered chemicals have been screened for toxicity. G. Pollution prevention is a strategy for implementing the precautionary principle. 17-5 How Do We Perceive Risks and How Can We Avoid the Worst of Them? A. There are scientific ways to evaluate and compare risk, to decide how much risk is acceptable, and to find affordable ways to reduce risk. Risk assessment involves identifying hazards and evaluating their associated risks. 1. The greatest risks are poverty and lifestyle choices. CASE STUDY: Cigarette smoking is the most preventable major cause of premature death. Smoking kills about 442,000 Americans per year. Some nations are beginning to enact smoking bans in certain areas, and in 2009 the FDA was given the power to classify and regulate tobacco as a drug. B. Estimation of risk for complex technology is difficult due to unpredictability of human behavior, human error, and sabotage. C. Most individuals are poor at evaluating the relative risks they face. Five factors can cloud this judgment: fear, degree of control, whether a risk is catastrophic, optimism bias, and instant gratification. 1. There are techniques to evaluate and reduce risk. These include comparing risks, determining how much risk you are willing to accept, determining the actual risk involved, and concentrating on making important lifestyle choices Teaching Tips: Large Lecture Classes: Start lecture with a recent event. The recent recall of plastic bottles due to Bisphenol A exposure is a good example (http://www.fda.gov/oc/opacom/hottopics/bpa.html). Ask students how many of them have used bottles with Bisphenol A and then ask them to gauge the risk that may have incurred from that use. Use clickers if possible and leave open the option of “there is no way to evaluate the risk”. Start class with a discussion of why it is so difficult to clearly identify the risk from exposure to chemicals. Small Lecture Classes: Begin class by breaking students into small groups. Give each group a card with the outlines of a human health issue described on the card (see below for suggestions). Tell each group they have 10 minutes to make a recommendation of what to do about the health problem. When you are done, compare the group responses to governmental responses to the same problems. In all likelihood, the responses from class will be more drastic than the actual governmental action and this is a good point to begin discussion of environmental health issues. Two examples: A) A disease is found in a form of meat that appears to be passed through sick animals and which can be passed on to humans. The disease can be identified in meat products once they are produced using a molecular test. Contrast student responses to this example with responses to the Mad Cow Problems in the U.S. B) A chemical is found in plastic bottles that may disrupt the endocrine system. In tests of food and liquids in these bottles, this chemical is present in detectable levels. Contrast student response to U.S. (and Canadian) responses to recent information about Bisphenol A. Key Terms carcinogens dose dose response curve emergent disease infectious disease mutagens nontransmissible disease pathogen response risk risk analysis risk assessment risk management teratogens toxic chemical toxicity toxicology transmissible disease Term Paper Research Topics 1. Environmental risks: brown lung disease and the textile industry; black lung disease and the coal-mining industry; asbestos as a carcinogen; exposure to toxic chemicals; earthquakes and volcanoes. 2. Lifestyle risks: health effects from secondary smoke; the rise in the lung cancer rate for women. 3. Transmissible disease risks: history of infectious disease control; vaccines and immunology; how smallpox was eradicated; waterborne diseases of the developing countries; the history of malaria; schistosomiasis; cholera; tuberculosis; AIDS. 4. When do smokers' rights infringe on nonsmokers' rights? 5. Is there equity in exposure to hazardous chemicals? Use coal fired power plants as an example. 6. Should utility regulators assume a linear dose-response curve in evaluating levels of exposure of the public to different hazardous chemicals? 7. How does the global pharmaceutical industry invest their research dollars and how does this compare to global health needs? 8. What are the major bio-terror threats to the U.S.? 9. What are primary threats to environmental health in the U.S. and how could they be addressed? 10. What is the human health risk of air pollution? Discussion Topics 1. What is the value of organic food (in terms of contaminants)? Is there a risk with conventional food? Answer: Organic food often has lower levels of pesticides and harmful chemicals due to restrictions on synthetic pesticide use. In contrast, conventional food may contain residues from these substances, posing potential health risks. However, both organic and conventional foods are generally considered safe when regulatory standards are met. 2. What kinds of risks do you take every day? Answer: Everyday risks include crossing the street, driving, using electronic devices, and consuming food and water. These activities carry potential hazards, such as accidents or exposure to contaminants, but are typically accepted as part of daily life. 3. What kinds of risks from the natural environment occur in your area? Answer: Common natural environmental risks might include extreme weather events (like storms or heatwaves), earthquakes, or air pollution. The specific risks depend on the geographical location and prevailing environmental conditions. 4. What kinds of risks are you exposed to each day over which you have no control? Answer: Risks beyond individual control include air and water pollution, food contamination, infectious diseases, and the actions of others (e.g., reckless driving by others). These risks are often managed through public health measures and regulations. 5. Do you feel that societal risks should be distributed equally among all citizens? Answer: Ideally, societal risks should be equitably distributed, ensuring no group disproportionately bears the burden. However, achieving perfect equity is challenging due to varying socio-economic conditions and geographic locations. 6. Should people who choose unhealthy lifestyles be covered by national health insurance? Answer: National health insurance should cover everyone, regardless of lifestyle choices, to ensure public health and fairness. However, incentives for healthier behaviors could be integrated to reduce overall healthcare costs and improve public health outcomes. 7. Does the government do enough to regulate industry and protect public health? Why or why not? Answer: The effectiveness of government regulation varies. While many countries have robust systems to protect public health, gaps and enforcement issues can still exist. The adequacy of regulation often depends on political will, resources, and public demand for safety. 8. How far should the precautionary principle go in terms of new chemical introductions? Answer: The precautionary principle should be applied rigorously, ensuring thorough testing and risk assessment before new chemicals are introduced. This approach minimizes potential harm and protects public health, even if it slows down innovation. 9. Do you buy organic food? Why or why not? How would you weigh cost versus health considerations? Answer: The decision to buy organic food depends on individual priorities, such as health, environmental concerns, and budget. While organic food may offer health benefits and reduce environmental impact, it can be more expensive. Balancing cost and perceived benefits is key to making an informed choice. Activities and Projects 1. Have local public health officials discuss with your class the types and frequency of diseases in the local area and describe efforts for disease control. Find out the common occupational health hazards in your community. 2. Invite a spokesperson for the American Cancer Society (or other appropriate organization) to address your class on the subject of "nonsmokers' rights." What specific things can a person do to minimize his or her passive exposure to cigarette smoke? What are the limits of smokers' rights to pollute air that nonsmokers cannot avoid breathing? Review the changes in attitude and behavior that people in the United States have shown toward smoking over the last 10 years. 3. Ask a nutritionist to explain to your students the problems with the typical U.S. diet and how to facilitate changes recommended by the National Academy of Sciences and the American Heart Association. 4. Assign several students to visit a store that specializes in organically grown and "natural" foods. Have them describe the advertising claims made on behalf of natural foods. 5. Have students watch Erin Brockovich and discuss the issues presented in the movie. 6. Have students download toxic air emission data for your state and identify the major sources and types of pollution in the state. 7. Invite the county health officer into class to discuss emerging animal diseases and their risk to humans. 8. Have your students obtain mortality and morbidity data for people living in poor and affluent sections of your community to determine the frequency and types of illness. Compare results with national statistics and attempt to explain any significant local differences. 9 What occupational health hazards are prevalent in your community? What is being done to protect workers from these on-the-job hazards? Have some students investigate this subject and report the results to the class. News Videos Bald Eagle Soars Again: Taken Off Endangered List; Environmental Science in the Headlines, 2008; DVD; ISBN 0495561908 Half the World Denied Basic Sanitation; The Brooks/Cole Environmental Science Video Library, 2009; DVD 0538733551 Additional Video Resources We all Live Downstream (Documentary, 1991) A look at pollution in the Mississippi River and the effects on human health. http://www.videoproject.com/wea-281-v.html NOVA: Can Buildings Make You Sick? Teachers Guide: http://www.pbs.org/wgbh/nova/teachers/activities/2217_building.html NOVA/Frontline: Harvest of Fear (Video series, PBS, 2001) http://www.pbs.org/wgbh/harvest/ A Civil Action (movie, 1999) The families of children who died sue two companies for dumping toxic waste. Web Resources USGS Site on emerging human/environmental health issues. http://health.usgs.gov/ Harvard University Center for Health and the Global Environment http://chge.med.harvard.edu/. World Health Organization Public health and the environment. http://www.who.int/phe/en/. World Health Organization Global AIDS statistics and information. http://www.who.int/hiv/en/. Suggested Answers to End of Chapter Questions Review Questions 1. Review the Key Questions and Concepts for this chapter on p. 437. Describe the potential risks from exposure to trace amounts of hormone mimics such as bisphenol A. Answer: • Bisphenol A mimics estrogen. In males, excess estrogens can cause feminization, smaller penis size, lower sperm count and hermaphroditism. There is controversy over whether hormone imposters pose a serious threat to human health. 2. Define risk and distinguish between risk assessment and risk management. Distinguish between possibility and probability. What is a pathogen? Give an example of a risk from each of the following: biological hazards, chemical hazards, physical hazards, cultural hazards, and lifestyle choices. Answer: • A risk is the probability of suffering harm from a hazard that can cause injury, disease, death, economic loss, or damage. • Risk assessment is the process of using statistical methods to estimate how much harm a particular hazard can cause to human health or to the environment. • Risk management involves deciding whether or how to reduce a particular risk to a certain level and at what cost. • Probability is a mathematical statement about the likelihood that harm will be suffered from a hazard. Scientists often state probability in terms such as: “The lifetime probability of developing lung cancer from smoking one pack of cigarettes per day is 1 in 250.” Whereas possibility indicates only that it could happen. • A pathogen is an organism that can cause disease in another organism. Examples are bacteria, viruses, parasites, protozoa, and fungi. • Biological hazard examples are bacteria, viruses, parasites, protozoa, and fungi. • Chemical hazards from harmful chemicals in air, water, soil, food, and human-made products such as the BPA from plastic bottles. • Physical hazards include fire, earthquakes, volcanic eruptions, floods, and storms. • Cultural hazards include criminal assault. • Lifestyle choices include smoking. 3. Distinguish among an infectious disease, a transmissible disease, and a nontransmissible disease, and give an example of each. In terms of death rates, what are the world’s four most serious infectious diseases? Distinguish between an epidemic and a pandemic of an infectious disease. Describe the causes and possible solutions for the increasing genetic resistance to commonly used antibiotics. Answer: • A nontransmissible disease is caused by something other than a living organism and does not spread from one person to another. Such diseases tend to develop slowly and have multiple causes. Examples include cardiovascular (heart and blood vessel) diseases, most cancers, asthma, and diabetes. An infectious disease is caused when a pathogen such as a bacterium, virus, or parasite invades the body and multiplies in its cells and tissues. Examples are tuberculosis, flu, malaria, and measles. A transmissible disease (also called a contagious or communicable disease) is an infectious disease that can be transmitted from one person to another. Examples are tuberculosis, flu, and measles. • The world’s four most serious infectious diseases are pneumonia and flu (bacteria and viruses), HIV/AIDS (virus), tuberculosis (bacteria), and diarrheal diseases (bacteria and viruses). • A large-scale outbreak of an infectious disease in an area or country is called an epidemic, and a global epidemic such as tuberculosis or AIDS is called a pandemic. • See Science Focus: Genetic Resistance to Antibiotics Is Increasing. 4. Describe the global threat from tuberculosis (TB). Describe the threat from flu. Describe the health threats from the global HIV/AIDS pandemic and list six ways to reduce this threat. Describe the threats from the hepatitis B virus. Define emergent diseases and describe the threat from the West Nile virus. Describe the threat from malaria for 40% of the world’s people and how we can reduce this threat. Answer: • Tuberculosis has spread rapidly worldwide since 1990, and kills about 1.7 million people per year. Ninety-five percent of TB cases occur in developing countries. Lack of screening, antibiotic resistant strains, population growth, urbanization and increased air travel have all contributed to the global increase in TB. • The biggest killer among viruses is the influenza or flu virus, which contributes to the deaths of about 1 million people a year—about 36,000 of them in the United States. Flu viruses are easily transmitted by the body fluids or airborne emissions of an infected person. A potent flu virus could create a world-wide pandemic that kills millions of people in only a few months. • The global spread of acquired immune deficiency syndrome (AIDS), caused by infection with the human immunodeficiency virus (HIV), is a major global health threat. The virus itself is not deadly, but it cripples the immune system and leaves the body vulnerable to infections such as tuberculosis (TB) and rare forms of cancer such as Kaposi’s sarcoma. The virus is transmitted from one person to another by unsafe sex, sharing of needles by drug users, infected mothers who pass the virus on to their offspring before or during birth, and exposure to infected blood. • A global strategy to slow the spread of AIDS should have five major priorities. First, reduce the number of new infections below the number of deaths. Second, concentrate on the groups in a society that are most likely to spread the disease such as sex workers, intravenous drug users, and soldiers. Third, provide free HIV testing and pressure people from high-risk groups to get tested. Fourth, implement mass advertising and education programs geared toward adults and school children to help prevent the disease. Fifth, provide free or low-cost drugs to help slow the progress of the disease. Sixth, increase funding for research for micro biocides which could help protect people from getting HIV/AIDS. • The third largest viral killer is the hepatitis B virus (HBV), which damages the liver and kills about a million people each year. It is transmitted in the same ways HIV is spread. • Emergent diseases are newly discovered or those that have been absent in human populations for at least 20 years. One is the West Nile virus, which is transmitted to humans by the bite of a common mosquito that becomes infected by feeding on birds that carry the virus. • About 1 in five people worldwide, mostly in Africa, are at risk of contracting malaria. Between one to two million people die from malaria each year. There is no vaccine. Malaria infects red blood cells and is transmitted by mosquitoes. Draining wetlands and spraying with insecticides decrease the number of disease-carrying mosquitoes. However, many species of mosquito have become resistant to pesticides and many of the malaria-causing microbes have become antibiotic-resistant. Ways to combat malaria include developing new anti-malarial drugs and new mosquito controls, as well as providing bed nets and window screens. Nutritional supplements (zinc and vitamin A) increase resistance in children. DDT, while being phased out world-wide, can be cheaply used to spray homes and greatly reduce the incidence of malaria. 5. Give three examples of problems being studied within the new field of ecological medicine. What are two ways in which people have exposed themselves to such threats? List five major ways to reduce the global threat from infectious diseases. Answer: • Ecological medicine studies the avian flu, HIV, SARS, West Nile virus and Lyme disease. Most people do not realize that pets such as rabbits, hamsters, and turtles can transfer various infectious diseases to humans. • Two ways people have exposed themselves to such threats include clearing and fragmenting forests, and the legal and illegal international trade in wild species. • Ways to prevent or reduce the incidence of infectious diseases, especially in developing countries include: a. Increase research on tropical diseases and vaccines. b. Reduce poverty. c. Decrease malnutrition. d. Improve drinking water quality. e. Reduce unnecessary use of antibiotics. f. Educate people to take all of an antibiotic prescription. g. Reduce antibiotic use to promote livestock growth. h. Require careful hand washing by all medical personnel. i. Immunize children against major viral diseases. j. Provide oral rehydration for diarrhea victims. k. Conduct global campaign to reduce HIV/AIDS. 6. What is a toxic chemical? Discuss the threat from PCBs. Distinguish among mutagens, teratogens, and carcinogens, and give an example of each. Describe the human immune, nervous, and endocrine systems and give an example of a chemical that can threaten each of these systems. Describe the toxic effects of the various forms of mercury and ways to reduce these threats. What are hormonally active agents, what risks do they pose, and how can we reduce these risks? Answer: • A toxic chemical is one that can cause temporary or permanent harm or death to humans and animals. • In 2004, the U.S. Environmental Protection Agency (EPA) listed arsenic, lead, mercury, vinyl chloride (used to make PVC plastics), and polychlorinated biphenyls (PCBs) as the top five toxic substances in terms of human and environmental health. PCBs are carcinogens teratogens, neurotoxins, and HAA. • Mutagens are chemicals or forms of radiation that cause mutations, or changes, in the DNA molecules found in cells, or that increase the frequency of such changes. Most mutations cause no harm but some can lead to cancers and other disorders. For example, nitrous acid (HNO2), formed by the digestion of nitrite (NO2 –) preservatives in foods, can cause mutations linked to increases in stomach cancer in people who consume large amounts of processed foods and wine with such preservatives. Harmful mutations occurring in reproductive cells can be passed on to offspring and to future generations. • Teratogens are chemicals that cause harm or birth defects to a fetus or embryo. Ethyl alcohol is a teratogen. Drinking during pregnancy can lead to offspring with low birth weight and a number of physical, developmental, behavioral, and mental problems. • Carcinogens are chemicals, types of radiation, or certain viruses that can cause or promote cancer—a disease in which malignant cells multiply uncontrollably and create tumors that can damage the body and often lead to premature death. Examples of carcinogens are arsenic, benzene, chloroform, formaldehyde, gamma radiation, nickel, PCBs, radon, certain chemicals in tobacco smoke, ultraviolet (UV) radiation, X-rays, and vinyl chloride. • The immune system consists of specialized cells and tissues that protect the body against disease and harmful substances by forming antibodies that render invading agents harmless. Some chemicals such as arsenic, methylmercury, and dioxins can weaken the human immune system and leave the body vulnerable to attacks by allergens and infectious bacteria, viruses, and protozoa. • Some natural and synthetic chemicals in the environment, called neurotoxins, can harm the human nervous system (brain, spinal cord, and peripheral nerves). Effects can include behavioral changes, learning disabilities, retardation, attention deficit disorder, paralysis, and death. Examples of neurotoxins are PCBs, methylmercury, arsenic, lead, and certain pesticides. • The endocrine system is a complex network of glands that releases tiny amounts of hormones into the bloodstreams of humans and other vertebrate animals. Low levels of these chemical messengers turn on and turn off bodily systems that control sexual reproduction, growth, development, learning ability, and behavior. Each type of hormone has a unique molecular shape that allows it to attach to certain cells, using a part of the cell called a receptor, and to transmit its chemical message. In this “lock-and-key” relationship, the receptor is the lock and the hormone is the key. PCBs can affect this system. • See Science Focus: Mercury’s Toxic Effects. 7. Define toxicology, toxicity, dose, and response. Give three reasons why children are more vulnerable to harm from toxic chemicals than are adults. Describe how the toxicity of a substance can be estimated by testing laboratory animals, and discuss the limitations of this approach. What is a dose-response curve? Describe how toxicities are estimated through use of case reports and epidemiological studies, and discuss the limitations of these approaches. Why do we know so little about the harmful effects of chemicals? Discuss the use of the precautionary principle and pollution prevention in dealing with health threats from chemicals. Answer: • Toxicology is the study of the harmful effects of chemicals on humans and other organisms. In effect, it is a study of poisons. • Toxicity is a measure of the harmfulness of a substance—its ability to cause injury, illness, or death to a living organism. • Dose is the amount of a harmful chemical that a person has ingested, inhaled, or absorbed through the skin. The effects of a particular chemical can also depend on the age of the person exposed to it. • Infants and young children are more susceptible to the effects of toxic substances than adults for three major reasons. First, they generally breathe more air, drink more water, and eat more food per unit of body weight than do adults. Second, they are exposed to toxins in dust or soil when they put their fingers, toys, or other objects in their mouth. And third, children usually have less well-developed immune systems and body detoxification processes than adults. • Scientists usually use mathematical models to extrapolate, or estimate, the effects of low-dose exposures based on the measured results of high-dose exposures. Then they extrapolate these results from test organisms to humans to estimate LD50 values for acute toxicity. Some scientists challenge the validity of extrapolating data from test animals to humans, because human physiology and metabolism often differ from those of the test animals. Scientists estimate the toxicity of a chemical by determining the effects of various doses of a chemical on test organisms and plotting the results in a dose-response curve. One approach is to determine the lethal dose—the dose that will kill an animal. A chemical’s median lethal dose (LD50) is the dose that can kill 50% of the animals (usually rats and mice) in a test population within an 18-day period. • Case reports are usually made by physicians and provide information about people suffering some adverse health effect or death after exposure to a chemical. Such information often involves accidental or deliberate poisonings, drug overdoses, homicides, or suicide attempts. Most case reports are not reliable sources for estimating toxicity because the actual dosage and the exposed person’s health status are often unknown. But such reports can provide clues about environmental hazards and suggest the need for laboratory investigations. Another source of information is epidemiological studies, which compare the health of people exposed to a particular chemical (the experimental group) with the health of a similar group of people not exposed to the agent (the control group). The goal is to determine whether the statistical association between exposure to a toxic chemical and a health problem is strong, moderate, weak, or undetectable. • Because of insufficient data and the high costs of regulation, federal and state governments do not regulate about 99.5% of the commercially used chemicals in the United States; many chemicals have not undergone extensive testing. • The precautionary principle advocates that when there is reasonable but incomplete scientific evidence of significant or irreversible harm to humans or the environment from a proposed or existing chemical or technology, we should take action to prevent or reduce the risk instead of waiting for more conclusive scientific evidence. Not everyone believes this. 8. What is risk analysis? In terms of premature deaths, what are the three greatest threats that humans face? Describe the health threats from smoking and what we can do to reduce these threats. Answer: • Risk analysis involves identifying hazards and evaluating their associated risks (risk assessment), ranking risks (comparative risk analysis), determining options and making decisions about reducing or eliminating risks (risk management), and informing decision makers and the public about risks (risk communication). • The three greatest threats that humans face causing premature deaths are the poverty/malnutrition/disease cycle, tobacco, and pneumonia and flu. • The WHO estimates that each year, tobacco contributes to the premature deaths of at least 5.4 million people from 25 illnesses including heart disease, lung cancer, other cancers, bronchitis, emphysema, and stroke. Passive smoking, or breathing secondhand smoke, also poses health hazards for children and adults. Children who grow up with smokers are more likely to develop allergies and asthma. Nonsmoking spouses of smokers have a 30% higher risk of both heart attack and lung cancer than do spouses of non-smokers. In 2006, the CDC estimated that each year, secondhand smoke causes an estimated 3,000 lung cancer deaths and 46,000 deaths from heart disease in the United States. See CASE STUDY: Death from Smoking. • Suggestions to decrease smoking include a. Adding a $ 3– 5 federal tax to the price of a pack of cigarettes in the United States. b. Classifying and regulating the use of nicotine as an addictive and dangerous drug under the U. S. Food and Drug Administration, c. Eliminating all federal subsidies and tax breaks to tobacco farmers and tobacco companies d. Using cigarette tax revenues to finance an aggressive anti-tobacco advertising. and education program. e. Smoking bans. In 2004, Ireland, Norway, and Scotland enacted bans on smoking in all indoor workplaces, bars, and restaurants. And in 2004, India banned smoking in public places, as well as tobacco advertising in the mass media and tobacco sales to minors. 9. How can we reduce the threats from the use of various technologies? What five factors can cause people to misjudge risks? List four principles that can help us evaluate and reduce risk. Answer: • We can reduce the major risks we face by becoming informed, thinking critically about risks, and making careful choices. • Five factors can cause people to see a technology or a product as being more or less risky than experts judge it to be: fear, degree of control we have, whether a risk is catastrophic (not chronic), some people suffer from optimism bias, and instant gratification. • Some guidelines for evaluating and reducing risk: a. Compare risks. Is there a risk of getting cancer by eating a charcoal-broiled steak once or twice a week for a lifetime? Yes, because almost any chemical can harm you if the dose is large enough. The question is whether this danger is great enough for you to worry about. In evaluating a risk, the key question is not “Is it safe?” but rather “How risky is it compared to other risks?” b. Determine how much risk you are willing to accept. For most people, a 1 in 100,000 chance of dying or suffering serious harm from exposure to an environmental hazard is a threshold for changing their behavior. However, in establishing standards and reducing risk, the U.S. EPA generally assumes that a 1 in 1 million chance of dying from an environmental hazard is acceptable. People involuntarily exposed to such risks believe that this standard is too high. c. Determine the actual risk involved. The news media usually exaggerate the daily risks we face in order to capture our interest and sell newspapers and magazines or gain television viewers. As a result, most people believe that the world is much more risk-filled than it really is. d. Concentrate on evaluating and carefully making important lifestyle choices, and you will have a much greater chance of living a longer, healthier, happier, and less fearful life. 10. What are this chapter’s three big ideas? Discuss how we can lessen the threats of harm from chemicals such as hormone mimics by applying the three scientific principles of sustainability. Answer: • The three big ideas are: a. We face significant hazards from infectious diseases such as flu, AIDS, diarrheal diseases, malaria, and tuberculosis, and from exposure to chemicals that can cause cancers and birth defects, and disrupt the human immune, nervous, and endocrine systems. b. Because of the difficulty in evaluating the harm caused by exposure to chemicals, many health scientists call for much greater emphasis on pollution prevention. c. Becoming informed, thinking critically about risks, and making careful choices can reduce the major risks we face. • We can use the three scientific principles of sustainability to help us lessen the threat of harm from chemicals. One way to do this involves shifting from nonrenewable fossil fuels to renewable energy, thereby reducing pollution and the threats from global warming. Another solution is to cut down on waste of energy and matter resources by reusing and recycling them, thereby helping to provide enough resources for most people to avoid poverty. We can also preserve habitats and species, thus eliminating vectors between animals and humans. Critical Thinking The following are examples of the material that should be contained in possible student answers to the end of chapter Critical Thinking questions. They represent only a summary overview and serve to highlight the core concepts that are addressed in the text. It should be anticipated that the students will provide more in-depth and detailed responses to the questions depending on an individual instructor’s stated expectations. 1. Should we ban the use of hormone mimics such as bisphenol A (Core Case Study) in products used by children younger than age 7? Should we ban them for use in all products? Explain. Answer: Yes, BPA should be banned from use in children’s products because of the developmental problems it has been linked with. Furthermore, it should be banned from all products because of the effects of exposure, which include brain damage, early puberty, prostate disease, breast cancer, heart disease, obesity, liver damage, reduced sperm count, impaired immune function, type 2 diabetes, and hyperactivity. 2. What are three actions you would take to reduce the global threats to human health and life from (a) tuberculosis, (b) HIV/AIDS, and (c) malaria? Answer: (a) Tuberculosis (TB): 1. Provide faster and cheaper diagnosis for TB in more hospitals. 2. Inform the public about symptoms in the early stages, since they usually go unnoticed. 3. Stress the importance of remaining on the medication/drugs, because people usually stop using them after symptoms go away, even though TB is still in their body and usually comes back. (b) HIV/AIDS: 1. Provide free HIV testing and encourage people to get tested. 2. Lower the cost of drugs so more people can be treated. 3. Educate groups of people susceptible to this disease and inform them about sexual abstinence, using condoms if sexually active, and unsafe sexual practices. (c) Malaria: 1. Find new technologies that can help treat malaria, such as safer and effective pesticides. 2. Plant more trees in marsh areas to reduce the presence of mosquitoes. 3. Spend more money on awareness and preventative procedures for the disease, such as mosquito nets. 3. Evaluate the following statements: a. We should not get worked up about exposure to toxic chemicals because almost any chemical, at a large enough dosage, can cause some harm. b. We should not worry much about exposure to toxic chemicals because, through genetic adaptation, we can develop immunities to such chemicals. c. We should not worry much about exposure to toxic chemicals because we can use genetic engineering to reduce our susceptibility to their effects. Answer: (a) This statement is completely false. Even small amounts of toxins can have a lasting effect on a person. Almost every toxic chemical can be harmful at high levels, this is true, but even good things for a human are bad for you in high amounts. Take calcium for example, a very essential vitamin for bones, but taken in high amounts may lead to kidney stones. For toxins, in particular, small doses can have disproportionately large impacts on health. (b) Even if there could be the development of immunity to a chemical, it would take many generations and, even then, may not occur. In the meantime, many people would suffer and die from what is ultimately a preventable exposure to a chemical. This is an ethically unacceptable situation. (c) We do not know how long it will take for these advances to come about. While genetic engineering could offer benefits in the long run, it is worth noting that, to date, the technique has not created many medical advances. Until these technologies become more mature, the precautionary principle is worth following. 4. Workers in a number of industries are exposed to higher levels of various toxic substances than is the general public. Should we reduce workplace levels allowed for such chemicals? What economic effects might this have? Answer: It is the business’ responsibility to have a safe environment for their workers to work in. In principle, there should not be any more pollutants in their workplace than anywhere else, but in practice, if this is not possible, workers should be provided with clear information about the risks they are taking and techniques should be used to reduce or mitigate this exposure to chemicals. In addition, since health costs are a major cost to industry, it is in the interest of a company to ensure that workers are not injured on the job. 5. Explain why you agree or disagree with the proposals for reducing the death toll and other harmful effects of smoking listed in the Case Study on p. 458. Do you believe there should be a ban on smoking indoors in all public places? Explain. Answer: The statistics are real and remarkable. The proposals presented look very practical and could easily be enacted. I believe “eliminating all federal subsidies and tax breaks to tobacco farmers” would be a strong policy that would raise the price of cigarettes and put some farmers out of business. I believe there should be a ban on smoking indoors. It is the smoker’s choice to smoke, but not everyone wants to breathe second-hand smoke, which is why there are smoking and non-smoking areas in places like restaurants, and in some places smoking has been banned outright. 6. What are the three major risks you face from (a) your lifestyle, (b) where you live, and (c) what you do for a living? Which of these risks are voluntary and which are involuntary? List three steps you could take to reduce these risks. Which of these steps do you already take or plan to take? Answer: (a) The food I eat affects me the most in my lifestyle. (b) The pollution from the city’s air affects me the most in my home town. (c) Sun rays affect me the most when I lifeguard. All are voluntary; I could eat better, move somewhere less polluted, and try a different job. I will try to change my eating habits, but the other things are too big or too difficult to change at the moment. 7. In deciding what to do about risks from chemicals in the country where you live, would you support legislation requiring the use of pollution prevention based on the precautionary principle? Explain. Answer: I would support this type of legislation. My observations are that it is generally much cheaper to prevent pollution than to address the health and environmental impacts of pollution after the fact. In addition, the ethical considerations of reducing environmental impacts and improving human health provide compelling reasons to reduce pollution now. 8. Congratulations! You are in charge of the world. List the three most important features of your program to reduce the risks from exposure to (a) infectious disease organisms and (b) toxic and hazardous chemicals. Answer: (a) I would primarily launch a prevention plan and educate the people on preventative measures. Knowing how to reduce the possibility of acquiring an infectious disease or organism would go a long way in reducing its spread. (b) I would improve oversight and strengthen regulations regarding toxic and hazardous chemicals. I would then develop a program of economic incentives to encourage individuals and businesses to reduce the production and use of these chemicals. 9. List three ways in which you could apply Concept 17-5 to make your lifestyle more environmentally sustainable while reducing the major risks you face. Answer: a. I can become better informed about the risks I face in my life and use that information to make better choices. b. I can evaluate factors in my own life that cause the greatest risk and prioritize those behaviors that cause the greatest risk. c. I can take many small steps, such as wearing my seat belt, to reduce my risk of injury or death in an accident. 10. List two questions that you would like to have answered as a result of reading this chapter. Answer: 1. How can a brand stay consistent across different regions? 2. How to manage brand equity in various market segments? Data Analysis The graph below shows the effects of AIDS on life expectancy at birth in Botswana, 1950-2000, and projects these effects to 2050. Study the chart and answer the questions below. 1. (a) By what percentage did life expectancy in Botswana increase between 1950 and 1995? (b) By what percentage is life expectancy in Botswana projected to decrease between 1995 and 2015? 2. (a) By what percentage is life expectancy in Botswana projected to increase between 2015 and 2050? (b) By what percentage is life expectancy in Botswana projected to decrease between 1995 and 2050? 1. Answer: (a) life expectancy in 1995 – life expectancy in 1950 = 65-46 = 19 years percent increase = 19 years/46 years x 100 = 41% (b) life expectancy in 1995 – life expectancy in 2015 = 65 – 33 = 32 years percent decrease = 32 years/65 years x 100 = 49% 2. Answer: (a) life expectancy in 2050 – life expectancy in 2015 = 44-33 = 11 years percent increase = 11 years/33 years x 100 = 33% (b) life expectancy in 1995 – life expectancy in 2050 = 65 – 44 = 21 years percent decrease = 21 years/65 years x 100 = 32% Chapter 18 Air Pollution Summary 1. The layers of the atmosphere are the troposphere, stratosphere, mesosphere, and thermosphere. 2. Major classes of air pollutants include carbon, sulfur, and nitrogen oxides, volatile organic compounds, suspended particulate matter, photochemical oxidants, radioactive substances, and hazardous chemicals that can cause health problems. Primary sources of these pollutants include cars, industry, and natural phenomena such as volcanic eruptions. 3. The two types of smog are the photochemical and the industrial, or gray-air, smog. 4. Acid deposition includes wet deposition of acidic rain, snow, fog, and cloud vapor with pH less than 5.6, and dry deposition of acidic particles. Major sources of acid deposition are nitrogen oxides produced during fossil fuel combustion and sulfur oxides produced primarily from coal-fired power plants. 5. Harmful effects of air pollution include various respiratory diseases, premature deaths, damage to plants, and materials such as buildings, cars, statues, etc. 6. We can reduce air pollution by reducing emission through the use of low-sulfur coal, shifting to less polluting fuels (e.g., coal to natural gas), removal of pollutants after combustion or lower emissions through the use of mass transit or alternative transportation, improving fuel efficiency, and tax incentives. Key Questions and Concepts 18-1 What Is the Nature of the Atmosphere? CORE CASE STUDY: Air pollution is no longer a localized phenomenon. South Asian Brown Clouds, containing dust, smoke, ash, soot, acidic compounds and particles of toxic metals, can cover areas the size of the continental United States and drift across oceans. Such pollution can be reduced fairly quickly with new standards and enforcement, but the worst polluting nations have a long way to go. A. The atmosphere consists of several layers with different temperatures, pressures, and composition. 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. B. About 75–80% of the earth’s air mass is found in the troposphere, the atmospheric layer closest to the earth’s surface. This layer extends about 11 miles above sea level at the equator and about 5 miles above the poles. 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. CASE STUDY: South Asian Brown Clouds are a cause of the gradual melting of Himalayan glaciers because they absorb sunlight and heat the air above the glaciers and when the soot falls on the surface, it decreases the glaciers ability to reflect radiant energy. At the same time, the brown clouds have helped to mask the impact of atmospheric warming because certain types of particles reflect sunlight back to space, helping to cool the earth’s surface beneath them. C. The stratosphere is the second layer of the atmosphere and extends from 11–30 miles above the earth’s surface. The concentration of ozone in this layer is much higher than in the troposphere. 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. 18-2 What Are the Major Outdoor Air Pollution Problems? A. Air Pollution: Air pollutants come mostly from natural sources and from burning fossil fuels. Primary pollutants are pollutants emitted into the air. They can react with one another and/or with air to form secondary pollutants. B. Outdoor air pollution comes mostly from natural sources and burning fossil fuels in vehicles and power and industrial plants. C. Major air pollutants include: 1. Carbon oxides 2. Nitrogen oxides and nitric acid 3. Sulfur dioxide and sulfuric acid 4. Particulates 5. Ozone 6. Volatile Organic Compounds (VOCs) CASE STUDY: Lead is a pollutant found in air, water, soil, plants and animals. It is a neurotoxin that is especially dangerous for children. The United States has phased out lead in gasoline and paint with the effect of a dramatic decrease in the percentage of children with blood lead levels above safety standards. Other nations however have not yet made this transition. SCIENCE FOCUS: Air pollutants can be detected and measured remotely with the use of unmanned aircraft, remote laboratories, and lasers. Other methods rely on biological indicators such as lichens. D. Industrial smog is a mix of sulfur dioxide, sulfuric acid, and suspended particles. China has the world’s highest levels of industrial smog. E. Photochemical smog is formed by the reaction of nitrogen oxides and volatile hydrocarbons under the influence of sunlight. All cities have some photochemical smog, though it is more common in places with sunny, warm and dry climates. F. Factors that reduce air pollution include: particles heavier than air settling out, rain and snow cleansing the air, salty sea spray washing out pollutants, winds sweeping pollutants away, and chemical reactions. G. Factors that increase air pollution include: buildings obstructing the wind, hills and mountains, high temperatures, emissions of VOCs, the movement of air pollutants to polar areas, and temperature inversions. H. Air pollution is influenced by atmospheric conditions. Inversions: A layer of warm air sitting on top of a layer of cool air near the ground can prevent outdoor pollutants from rising and dispersing. 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. This is a particular problem for cities in a valley (e.g., Los Angeles). 18-3 What Is Acid Deposition and Why Is It a Problem? A. Acid Deposition: Sulfur dioxide, nitrogen oxides, and particulates react in the atmosphere to produce acidic chemicals that travel long distances before coming back to earth. Acidic particles remain in the atmosphere for 2–14 days, depending on the prevailing winds, precipitation, and other weather patterns. The acidic substances return to earth in one of two forms: 1. Wet deposition as acidic rain, snow, fog, and cold vapor with a pH less than 5.6. 2. Dry deposition as acidic particles. B. Acid deposition can cause or worsen respiratory disease, attack metallic and stone objects, decrease atmospheric visibility, and kill fish. C. Acid deposition can deplete some soil nutrients, release toxic ions into soil, and weaken plants that become susceptible to other stresses. Effect of acid deposition on plants is caused partly by chemical interaction in the soils. D. The best solutions are preventative approaches that reduce or eliminate emissions of sulfur dioxide, nitrogen oxides, and particulates. E. Between 1980 and 2008 air pollution laws in the US reduced emissions dramatically, helping to reduce the acidity of rainfall in very large regions. 18-4 What Are the Major Indoor Air Pollution Problems? A. Indoor air pollution is usually a much greater threat to human health than outdoor air pollution. EPA studies have shown that levels of 11 common pollutants are 2–5 times greater inside homes and commercial buildings than outside. Inside cars in traffic-clogged areas the pollution may be 18 times higher than outside. Health risks are magnified because people usually spend 70–98% of their time indoors or in vehicles. 1. Pesticides and lead residues can collect in carpets and on furnishings. 2. Living organisms and the excrement can pollute indoor air. 3. Airborne spores of molds and mildews can be a source of indoor air pollution. B. The four most dangerous indoor air pollutants in more-developed countries are tobacco smoke, formaldehyde, radioactive radon-222 gas and very small particles from emissions. CASE STUDY: Radon-222 gas is found in some soils and rocks, and can seep into some homes and increase the risk of lung cancer. Radon is produced by the radioactive decay of uranium-238. Radon gas tends to be pulled into homes because of the slightly lower atmospheric pressure inside most homes. Radon is thought to be the second leading cause of lung cancer deaths each year in the U.S. 18-5 What Are the Health Effects of Air Pollution? A. The respiratory system has several ways to help protect you from air pollution. Hairs in the nose filter out large particles. Prolonged or acute expose to air pollutants can overload or break down the natural defenses. Several respiratory diseases can develop such as asthma, lung cancer, chronic bronchitis, and emphysema. People with respiratory diseases, older adults, infants, pregnant women, and people with heart disease are especially vulnerable to air pollution. B. Each year, air pollution kills about 2.4 million people, mostly from indoor air pollution in developing countries. Air pollution deaths in the U.S. range from 150,000 to 350,000 people per year. 18-6 How Should We Deal with Air Pollution? A. Clean Air Acts in the United States have greatly reduced outdoor air pollution from six major pollutants. The U.S. Congress passed Clean Air Acts in 1970, 1977, and 1990. National air quality standards (NAAQS) were established for six outdoor criteria pollutants. 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. B. The combined emissions of six major pollutants decreased by 54% between 1980 and 2008. 57% of Americans live in areas where air is unhealthy to breathe part of the year. CASE STUDY: There has been a dramatic reduction of outdoor air pollution in the United States since 1970. Still. Scientists call for strengthening air pollution laws by putting greater emphasis on prevention, sharply reducing emissions, improving fuel efficiency standards, more strictly regulating emissions from motorcycles and two-cycle engines, more strictly regulating airports and ocean-going ships, reducing indoor air pollution, and increasing the monitoring of air pollution. C. Allowing producers of air pollutants to buy and sell government air pollution allotments in the marketplace can help reduce emissions. The Clean Air Act of 1990 allows an emissions trading policy that permits companies to buy and sell SO2 pollution rights. 1. Success of these programs is dependent upon how low the initial cap is set, and how often it is lowered. D. There are a number of ways to prevent and control air pollution from coal-burning facilities and motor vehicles. See page 487. Indoor air pollution is a greater threat to human health, but little effort has been spent on reducing it. Teaching Tips: Large Lecture Classes: Start the lecture by asking how many students live in basement apartments, and then asking how many of them have had the apartment tested for Radon. Ask how many live in a location near a furnace and how many have CO monitors installed. When you reach the radon section, revisit the results and ask whether a landlord should have responsibility to test for Radon. You can also highlight that Radon is an alpha emitter and therefore particularly dangerous when attached to particles—mention that this is particularly a problem for smokers since the particulates can carry radon into the lungs. Smaller Lecture Classes: Ask students to characterize sources of indoor and outdoor air pollution on campus before coming to class. Have students arrive with a list of five potential sources of air pollution and the types of pollution that would be generated by these sources. Organize these lists as a class and ask the class to rank the types of pollution from highest potential risk to lowest risk. Use the list to generate a discussion about prioritizing air pollution control measure, costs of air pollution control, and who should bear the responsibility for air pollution control. Key Terms acid deposition air pollution atmospheric pressure carbon oxides industrial smog nitrogen oxides nitric acid ozone ozone layer particulates photochemical smog primary pollutants secondary pollutants stratosphere sulfur dioxide sulfuric acid temperature inversion troposphere volatile organic compounds (VOCs) Term Paper Research Topics 1. Outdoor air pollution: the geographic distribution of air quality problems; air pollution and major ecosystem disruption; fine particulates as a health hazard; the history of air pollution; the air pollution disaster in Donora, Pennsylvania; reducing urban heat island effects. 2. Indoor air pollution: radon gas; asbestos; second-hand smoke; formaldehyde: sources, health effects, and control measures for each. 3. Acid deposition: tall smokestacks and acid deposition; acid deposition in the northeastern United States; Germany's waldsterben; liming lakes; acid deposition and freshwater ecosystems. 4. Smog: how and where it is formed; what can be done to reduce it. 5. How much air pollution should we tolerate and what criteria should we use to decide? 6. Methods of assessing and cleaning up air pollution: scientific methods for measuring indoor and outdoor air pollutants; methods for measuring automobile emissions; stack scrubber technology; catalytic converters and their problems; electric automobiles. 7. National Policy: The Clean Air Act; the EPA's record on enforcement of the Clean Air Acts; changes in regulations on smoking in public places over the last decade; emissions trading policy. 8. International Policy: the London air pollution cleanup; air pollution in Eastern Europe; joint responsibility of Canada and the United States for acid deposition in the Great Lakes region. 9. Cap and Trade approaches to air quality. 10. Comparison of European versus U.S. approaches to air pollution regulation. Discussion Topics 1. How does the idea of environmental justice apply to air pollution? What are the issues? Answer: Environmental justice in air pollution involves ensuring that all communities, especially marginalized and low-income ones, are not disproportionately exposed to harmful pollutants. Issues include inequitable distribution of pollution sources, such as factories or highways, leading to health disparities and reduced quality of life in affected areas. 2. What are the particular local air quality problems? Answer: Local air quality problems can vary but often include high levels of particulate matter, ground-level ozone, and emissions from vehicles or industrial sources. These pollutants can cause respiratory issues, contribute to climate change, and harm ecosystems. 3. Who should pay for air quality regulation? Answer: The costs of air quality regulation should be shared by government entities, industries responsible for pollution, and potentially the public through taxes. This shared responsibility ensures that regulations are funded, polluters are held accountable, and public health is protected. 4. How much effort should we put into clean air technologies? How much would you be willing to pay? Answer: Significant effort should be put into developing and implementing clean air technologies to reduce pollution and protect public health. Investment should balance technological feasibility and economic costs. Individuals may be willing to pay higher taxes or utility rates to support these advancements, depending on the perceived benefits. 5. Would your perspective on air pollution be different if you had respiratory problems? What if you lived next to a major highway? Answer: Having respiratory problems or living near a major highway would likely heighten concern about air pollution due to direct health impacts and exposure. This personal experience could lead to greater support for stricter regulations and cleaner technologies to mitigate the associated risks. Attitudes and Values 1. Is clean air a basic right? Answer: Many argue that clean air should be considered a basic right due to its fundamental role in health and well-being. Ensuring access to clean air aligns with principles of environmental justice and human rights, recognizing that everyone deserves a healthy environment. 2. Who is responsible for air pollution? Answer: Responsibility for air pollution typically falls on both industrial and individual sources. Industries that emit pollutants, vehicles that burn fossil fuels, and even agricultural practices contribute to air pollution. Governments and regulatory bodies also play a role in enforcing standards and reducing emissions. 3. What obligation is there to reduce the ecological impacts of air pollution? Why? Answer: There is a significant obligation to reduce the ecological impacts of air pollution to protect ecosystems, biodiversity, and overall environmental health. Air pollution can damage plant life, water sources, and wildlife, leading to long-term ecological consequences that affect all living organisms. 4. What role should the federal, state, and local government play in regulating air pollution? Answer: Federal, state, and local governments each have crucial roles in regulating air pollution. The federal government sets national standards and regulations, states implement and enforce these standards, and local governments address specific community issues and pollution sources, ensuring comprehensive air quality management. 5. Would privatizing the atmosphere be logistically feasible? How might privatization of the atmosphere improve/deteriorate the quality of the air we breathe? Answer: Privatizing the atmosphere is not logistically feasible due to the nature of air as a shared resource. Privatization could lead to inconsistent air quality standards and potentially worsen pollution if profit motives outweigh environmental concerns. Public regulation ensures that air quality is managed for the collective good. Activities and Projects 1. Visit the chemistry department or invite a chemistry professor to visit your class to discuss measurement of air pollution. Have the professor show you instruments for measuring air pollutants in the parts per million or lower range and explain the difficulty of making accurate and reproducible measurements of such low concentrations. Inquire if the professor has insights into the effects on environmental policy of being able to measure parts per billion and parts per trillion. 2. As a class exercise, interview farmers, foresters, and wildlife experts in your area to determine whether they know of any plant, fish, or animal damage from air pollution. Is acid deposition a problem in your locale? If so, what is the extent of the damage? Is anything being done about it? 3. Have a doctor or health official visit your class to explain and illustrate the various types of lung disease and damage that can result from air pollution. If possible, have the expert show you specimens (or photographs) of lung tissue from a young child, an urban dweller, a rural dweller, a smoker, a nonsmoker, and from patients suffering from lung cancer, emphysema, and chronic bronchitis. 4. Have an epidemiologist visit the class to present available evidence on relationships between air pollution and human health. 5. Have someone knowledgeable about automobile engine design visit your class and discuss some of the problems associated with designing engines that pollute less and deliver better fuel economy. 6. Have a meteorologist visit your class to discuss the weather and climate patterns of your locale. Find out if there are any atmospheric patterns in your area that aid or hinder air pollution effects. 7. Have students survey corrosion and damage to buildings and statues that result from air pollution in your area. Try to estimate the total cost per year for replacement, repair, cleaning, and painting. Who pays for this? 8. Have your class make a community-wide survey of particulate fallout and plot the results on a map of your area. Obtain some small, open-top boxes—all the same size. Use masking tape to stick a clean piece of white typing paper in the bottom of each box. Place the boxes at various locations for a period of 24 hours and compare the relative darkness on the paper. Does the particulate fallout vary with height? (Try some rooftops.) Compare your map with any official air pollution monitor locations or test spots. Do the official monitors give a realistic picture? See if you can trace the major causes in heavy fallout areas. You can vary the experiment by using a strip of exposed masking tape to collect the solids and then observe or count them under a microscope. 9. As a class project, test the vital capacity of the lungs of each member of the class. Your vital capacity is the total volume of air you can exhale in one breath. Low vital capacity indicates that only a small fraction of the volume of a person's lungs is being used for breathing and obtaining oxygen. It can also lead to an enlarged heart because the heart must work harder to pump blood through the lungs. Test lung capacity as a function of age and sex, and on track team members, smokers and nonsmokers, urban and rural dwellers, and people with asthma, bronchitis, and emphysema. A portable vital-capacity tester can easily be made by inserting a two-hole stopper in a gallon jug. Put a short glass tube with a 6-inch piece of rubber tubing attached through one hole and a long glass tube that almost reaches the bottom of the jug through the other hole. Attach a 15- to 24-inch rubber tube to this glass tube. Fill the jug half to two-thirds full of water. Fix the stopper tightly, take a deep breath, blow into the short rubber tube to force the water out of the jug and into another jug or container, and measure the water in the second jug. Run several trials and get an average for each person tested. 10. Ask your students to conduct a class or school survey to see what percentage of the respondents: (a) can identify the major pollutants from automobiles, (b) know what air pollution devices are on their cars, (c) have their engines tuned on a regular basis, and (d) would be willing to pay extra for more effective air pollution control devices (including the maximum they would pay). News Videos Carbon Dioxide’s Impact on Our Oceans; The Brooks/Cole Environmental Science Video Library, 2009; DVD 0538733551 China’s Deadly Pollution; The Brooks/Cole Environmental Science Video Library, 2009; DVD 0538733551 Environmental Victory: Green Decision; Environmental Science in the Headlines, 2007; DVD; ISBN 0495385433 Pollution and Women’s Health; Environmental Science in the Headlines, 2007; DVD; ISBN 0495385433 Additional Video Resources Acid Rain: The Invisible Threat (Video plus lab) Hands-on lab activities plus video. http://www.kelvin.com/Merchant2/merchant.mv?Screen=PROD&Store_Code=K&Product_Code=360042 Air: State of the Earth (Video, Online) National Geographic video available through their website about the global effects of local pollution. http://video.nationalgeographic.com/video/player/environment/environmental-threats-environment/state-of-the-earth/air.html Clearing California’s skies (Video, Online) A look at the history of smog, and attempts to reduce it in California. http://www.arb.ca.gov/videos/clskies.htm Forecast Earth: Air Aware An EPA-sponsored segment, Air Aware, highlights how air quality can affect people. http://www.airnow.gov/index.cfm?action=movie.main The Habitable Planet: A Systems Approach to Environmental Science: Atmospheric Pollution (Documentary series, 2007). The eleventh video in this series explores the effects of air pollution. http://www.learner.org/resources/series209.html Nova: Dimming the Sun How air pollution has helped mitigate some of the effects of global warming. Main Website: http://www.pbs.org/wgbh/nova/sun/ Teacher’s Guide: http://www.pbs.org/wgbh/nova/teachers/programs/3310_sun.html NOVA: Can Buildings Make You Sick? Teachers Guide: http://www.pbs.org/wgbh/nova/teachers/activities/2217_building.html Web Resources US Environmental Protection Agency Air Pollution information site. http://www.epa.gov/ebtpages/airairpollutants.html Current U.S. Air Quality Assessments http://www.airnow.gov U.S. EPA Trends in air quality in the U.S. http://www.epa.gov/airtrends/. American Academy of Family Physicians Air pollution health effects. http://familydoctor.org/online/famdocen/home/common/asthma/triggers/085.printerview.html. Suggested Answers to End of Chapter Questions Review Questions 1. Review the Key Questions and Concepts for this chapter on p. 466. Describe the nature and harmful effects of the massive South Asian Brown Clouds (Core Case Study). Answer: • A 3 kilometers thick cloud of pollution— called the Asian Brown Cloud— stretches nearly continuously across much of India, Bangladesh, the industrial heart of China, and the open sea east of this area. It is made up of dust, smoke, and ash resulting from drought and the clearing and burning of forests for planting crops, as well as acidic compounds, soot, toxic metals such as mercury and lead, hundreds of organic compounds, and fly ash produced by the burning of coal, diesel, and other fossil fuels in industries, motor vehicles, and homes. • The cloud reduces photosynthesis. Acids fall to the surface and damage crops, trees, and aquatic life in lakes. Pollution in the cloud is estimated to contribute to at least 700,000 premature deaths every year. • Satellite measurements show that it takes about 2 weeks for long- lived air pollutants to circle the world. Thus, the Asian Brown Cloud is bad news for other parts of the world. The EPA estimates that on certain days, nearly 25% of the particulate matter, 77% of the black carbon, and 33% of the toxic mercury in the skies above Los Angeles, California, can be traced to coal-fired power plants, smelters, diesel trucks, and dust storms caused by drought and deforestation in China. 2. Define atmospheric pressure, troposphere, stratosphere, and ozone layer. Describe the major differences between the troposphere and stratosphere. Answer: • Atmospheric pressure is force per unit area of a column of air. • The troposphere is the atmospheric layer closest to the earth’s surface. This layer extends only about 17 kilometers (11 miles) above sea level at the equator and 8 kilometers (5 miles) over the poles. • The stratosphere extends from about 17 to about 48 kilometers (from 11 to 30 miles) above the earth’s surface. • Much of the atmosphere’s small amount of ozone (O3) is concentrated in a portion of the stratosphere called the ozone layer, found roughly 17–30 kilometers (11–19 miles) above sea level. Stratospheric ozone is produced when some of the oxygen molecules there interact with ultraviolet (UV) radiation emitted by the sun (3 O2 + UV 2 O3). • The stratosphere contains less matter than the troposphere. Its composition is similar, with two notable exceptions: its volume of water vapor is about 1/1,000 that of the troposphere and its concentration of ozone (O3) is much higher. 3. What is air pollution? Distinguish between primary pollutants and secondary pollutants and give an example of each. List the major outdoor air pollutants and their harmful effects. Describe the effects of lead as a pollutant and how we can reduce our exposure to this chemical. Describe a chemical method and a biological method for detecting air pollutants. Answer: • Air pollution is the presence of chemicals in the atmosphere in concentrations high enough to harm organisms, ecosystems, or human made materials, or to alter climate. Air pollutants come from natural and human sources. • Primary pollutants are harmful chemicals emitted directly into the air from natural processes and human activities. While in the atmosphere, some primary pollutants react with one another and with other normal components of air to form new harmful chemicals, called secondary pollutants. Primary pollutants include most hydrocarbons, most suspended particles, CO2, SO2, NO, and NO2. Secondary pollutants include SO3, HNO3, H2SO4, H2O2, O3, PANs, most NO3, and SO4– salts. • Carbon monoxide (CO) is a colorless, odorless, and highly toxic gas that forms during the incomplete combustion of carbon-containing materials. At high levels, CO can cause headache, nausea, drowsiness, mental impairment, collapse, coma, and death. • Carbon dioxide (CO2) is a colorless, odorless gas that contributes to climate change. • Nitric oxide (NO) is a colorless gas that forms when nitrogen and oxygen gas in air react at the high-combustion temperatures in automobile engines and coal-burning power and industrial plants. In the air, NO reacts with oxygen to form nitrogen dioxide (NO2), a reddish-brown gas. Collectively, NO and NO2 are called nitrogen oxides (NOX). Some of the NO2 reacts with water vapor in the air to form nitric acid (HNO3) and nitrate salts (NO3–)—components of harmful acid deposition,. Both NO and NO2 play a role in the formation of photochemical smog—a mixture of chemicals formed under sulfur dioxide and sulfuric acid. • Sulfur dioxide (SO2) is a colorless gas with an irritating odor. In the atmosphere, SO2 can be converted to aerosols, which consist of microscopic suspended droplets of sulfuric acid (H2SO4) and suspended particles of sulfate (SO4 2–) salts that return to the earth as a component of acid deposition. Sulfur dioxide, sulfuric acid droplets, and sulfate particles reduce visibility and aggravate breathing problems. They can also damage crops, trees, soils, and aquatic life in lakes; and they corrode metals and damage paint, paper, leather, and stone on buildings and statues. And they are a major component of the Asian Brown Cloud. Suspended particulate matter (SPM) consists of a variety of solid particles and liquid droplets small and light enough to remain suspended in the air for long periods. Such particulates are a major component of the Asian Brown Cloud. Ozone (O3), a colorless and highly reactive gas, is a major ingredient of photochemical smog. It can cause coughing and breathing problems, aggravate lung and heart diseases, reduce resistance to colds and pneumonia, and irritate the eyes, nose, and throat. • Volatile organic compounds (VOCs): Organic compounds that exist as gases in the atmosphere or that evaporate into the atmosphere are called volatile organic compounds (VOCs). Examples are hydrocarbons emitted by the leaves of many plants, and methane (CH4), a greenhouse gas that is 20 times more effective per molecule than CO2 at warming the atmosphere through the greenhouse effect. • Lead is a highly toxic pollutant. Because it is a chemical element, lead (Pb) does not break down in the environment. This potent neurotoxin can harm the human nervous system, especially in young children. Each year, 12,000–16,000 American children younger than age 9 are treated for acute lead poisoning, and about 200 die. About 30% of the survivors suffer from palsy, partial paralysis, blindness, and mental retardation. Children younger than age 6 and unborn fetuses, even with quite low blood levels of lead, are especially vulnerable to nervous system impairment, lowered IQ. For examples of prevention see Figure 18-7. • Air pollution can be detected with the use of chemical instruments and satellites. Researchers have developed a mobile laboratory that uses sophisticated instruments to make instant measurements of primary and secondary air pollutants from motor vehicles, factories, and other sources. Biological indicators, such as lichens, can be used to detect the presence of air pollution. Lichens are good biological indicators of air pollution because they continually absorb air as a source of nourishment. A highly polluted area may have no lichens or only gray-green crusty species. An area with moderate air pollution may have orange crusty lichens. 4. Distinguish between industrial smog and photochemical smog in terms of their chemical composition and formation. List and briefly describe five natural factors that help to reduce outdoor air pollution and six natural factors that help to worsen it. What is a temperature inversion and how can it affect air pollution levels? Answer: • Industrial smog consisting mostly of an unhealthy mix of sulfur dioxide, suspended droplets of sulfuric acid, and a variety of suspended solid particles that give the resulting smog a gray color, which is why it is sometimes called gray-air smog. When burned, most of the carbon in coal and oil is converted to carbon monoxide (CO) and carbon dioxide (CO2). The sulfur compounds they contain react with oxygen to produce sulfur dioxide (SO2) gas, some of which reacts with water vapor and is converted to tiny suspended droplets of sulfuric acid (H2SO4). Some of these droplets react with ammonia (NH3) in the atmosphere to form solid particles of ammonium sulfate [(NH4) 2SO4]. • Photochemical smog is a mixture of primary and secondary pollutants formed under the influence of UV radiation from the sun. Its begins when exhaust from morning commuter vehicles releases large amounts of NO and VOCs into the air over a city. The NO is converted to reddish- brown NO2, explaining why photochemical smog is sometimes called brown- air smog. When exposed to ultraviolet radiation from the sun, some of the NO2 reacts with VOCs released by certain trees, motor vehicles, and some businesses. The resulting photochemical smog is a mixture of ozone, nitric acid, aldehydes, peroxyacyl nitrates ( PANs), and other secondary pollutants. Collectively, NO2, O3, and PANs in this chemical brew are called photochemical oxidants because these damaging chemicals can react with and oxidize certain compounds in the atmosphere or inside your lungs. • Five natural factors help reduce outdoor air pollution. First, particles heavier than air settle out as a result of gravitational attraction to the earth. Second, rain and snow help cleanse the air of pollutants. Third, salty sea spray from the oceans washes out many pollutants from air that flows from land over the oceans. Fourth, winds sweep pollutants away and mix them with cleaner air. Fifth, some pollutants are removed by chemical reactions. • Six other factors can increase outdoor air pollution. First, urban buildings slow wind speed and reduce dilution and removal of pollutants. Second, hills and mountains reduce the flow of air in valleys below them (Figure 15-4) and allow pollutant levels to build up at ground level. Third, high temperatures promote the chemical reactions leading to formation of photochemical smog. Fourth, emissions of volatile organic compounds (VOCs) from certain trees and plants in heavily wooded urban areas can play a large role in the formation of photochemical smog. A fifth factor—the so-called grasshopper effect—occurs when air pollutants are transported by evaporation and winds from tropical and temperate areas through the atmosphere to the earth’s polar areas, where they are deposited. • Under certain atmospheric conditions, a layer of warm air can temporarily lie atop a layer of cooler air nearer the ground, creating a temperature inversion. Because the cooler air is denser than the warmer air above it, the air near the surface does not rise and mix with the air above. If this condition persists, pollutants can build up to harmful and even lethal concentrations in the stagnant layer of cool air near the ground. 5. What is acid deposition and how does it form? What are its major environmental impacts on vegetation, lakes, human-built structures, and human health. List three major ways to reduce acid deposition. Answer: • Acidic substances remain in the atmosphere for 2–14 days, depending mostly on prevailing winds, precipitation, and other weather patterns. During this period they descend to the earth’s surface in two forms: wet deposition consisting of acidic rain, snow, fog, and cloud vapor, and dry deposition consisting of acidic particles. The resulting mixture is called acid deposition—sometimes called acid rain. • Acid deposition damages statues and buildings, contributes to human respiratory diseases, and can leach toxic metals (such as lead and mercury) from soils and rocks into lakes used as sources of drinking water. Acid deposition harms aquatic ecosystems and forests. • Reduce by reducing coal use, burning low-sulfur coal, increasing natural gas use, increasing use of renewable energy resources, removing SO2 particulates and NOx from smokestack gases, removing NOx from motor vehicular exhaust, taxing emissions of SO2, and reducing air pollution by improving energy efficiency. 6. What is the major indoor air pollutant in many developing countries? What are the top four indoor air pollutants in the United States? Describe indoor air pollution by radon- 222 and what can be done about it. Answer: • In developing countries, the indoor burning of wood, charcoal, dung, crop residues, coal, and other cooking and heating fuels in open fires or in unvented or poorly vented stoves exposes people to dangerous levels of particulate air pollution. • According to the EPA and public health officials, the four most dangerous indoor air pollutants in developed areas are tobacco smoke; formaldehyde emitted from many building materials and household products; radioactive radon-222 gas, which can seep into houses from underground rock deposits; and very small (ultrafine) particles. • Radon- 222 is a colorless, odorless, radioactive gas that is produced by the natural radioactive decay of uranium- 238, small amounts of which are contained in most rocks and soils. Radon gas seeps upward through the soil. When released outdoors, it disperses quickly in the air and decays to harmless levels. However, in buildings, radon gas can enter through cracks in foundations and walls and other openings, and build up to high levels, especially in unventilated lower levels of homes and buildings. Radon- 222 gas quickly decays into solid particles of other radioactive elements such as polonium- 210, which if inhaled, expose lung tissue to large amounts of ionizing radiation which can lead to lung cancer. • The EPA recommends that radon levels should be monitored continuously in the main living areas of homes for 2 months to a year. • Remedies include sealing cracks in the foundation and walls, increasing ventilation by cracking a window or installing vents, and using a fan to create cross ventilation. 7. Briefly describe the human body’s defenses against air pollution, how they can be overwhelmed, and the illnesses that can result. Approximately, how many people die prematurely from air pollution each year in the world and in the United States? What percentage of these deaths are caused by indoor air pollution? Answer: • Your respiratory system has a number of ways to protect you from air pollution. Hairs in your nose filter out large particles. Sticky Hairs in your nose filter out large particles. Sticky mucus in the lining of your upper respiratory tract captures smaller (but not the smallest) particles and dissolves some gaseous pollutants. Sneezing and coughing expel contaminated air and mucus when pollutants irritate your respiratory system. In addition, hundreds of thousands of tiny mucus-coated cilia line your upper respiratory tract. They continually wave back and forth and transport mucus and the pollutants they trap to your throat where they are swallowed or expelled. • Prolonged or acute exposure to air pollutants can overload or break down these natural defenses. Fine and ultrafine particulates get lodged deep in the lungs, contributing to lung cancer, asthma attack, heart attack, and stroke. Years of smoking or breathing polluted air can lead to other lung ailments such as chronic bronchitis or emphysema. • At least 2.4 million people worldwide die prematurely each year from the effects of air pollution. • In the United States, the EPA estimates that the annual number of deaths related to indoor and outdoor air pollution ranges from 150,000 to 350,000 people. • Indoor air pollution causes about 1.6 million deaths per year, or 67%. 8. Describe air pollution laws in the United States. Summarize the positive effects of such laws and discuss how the laws can be improved. List the advantages and disadvantages of using an emissions trading program. Summarize the major ways to reduce emissions from power plants and motor vehicles. What are four ways to reduce indoor air pollution? Answer: • The United States provides an excellent example of how a regulatory approach can reduce air pollution . The U.S. Congress passed the Clean Air Acts in 1970, 1977, and 1990. With these laws, the federal government established air pollution regulations for key pollutants that are enforced by states and major cities • According to a 2007 EPA report, the combined emissions of the six major air pollutants decreased 49% between 1980 and 2006, even with significant increases during the same period in gross domestic product ( up 121%), vehicle miles traveled ( up 101%), population ( up 32%), and energy consumption ( up 29%). The decreases in emissions during this period were 97% for lead ( Pb), 52% for volatile organic compounds ( VOCs), 50% for carbon monoxide ( CO), 47% for sulfur dioxide ( SO2), 33% for nitrogen oxides ( NOx), 28% for suspended particulate matter ( PM10), • See CASE STUDY: U.S. Air Pollution Laws Can Be Improved. 9. List the advantages and disadvantages of using an emissions trading program. Summarize the major ways to reduce emissions from power plants and motor vehicles. What are four ways to reduce indoor air pollution? Why is preventing air pollution more important than controlling it? Answer: • Proponents of an emissions trading program say it is cheaper and more efficient than government regulation of air pollution control. Critics of this approach contend that it allows utilities with older, dirtier power plants to buy their way out of their environmental responsibilities and continue polluting. And without strict government oversight, this approach makes cheating possible, because it is based largely on self-reporting of emissions. • Ways to reduce emissions from power plants include: burn low-sulfur coal, remove sulfur from coal, convert coal to a liquid or gaseous fuel, and shift to less polluting energy sources. Ways to reduce emissions from motor vehicles include: use mass transit; walk or bike; use less polluting fuels; improve fuel efficiency; get older, polluting cars off the road; and give large tax write-offs or rebates for buying low-polluting, energy efficient vehicles. • Ways to prevent and reduce indoor air pollution include: clean ceiling tiles and line AC ducts to prevent release of mineral fibers; ban smoking or limit it to well-ventilated areas; set stricter formaldehyde emissions standards for carpet, furniture, and building materials; prevent radon infiltration; use office machines in well-ventilated areas; and use less polluting substitutes for harmful cleaning agents, paints, and other products. • Prevention goes a step further than control, eliminating the problem altogether, rather than focusing efforts on ameliorating the problem. 10. What are the three big ideas for this chapter? Discuss the relationship between the Asian Brown Cloud (Core Case Study) and the ways in which people have violated the three principles of sustainability. Describe how we can apply these principles to the problems of air pollution. Answer: • The three big ideas are: 1. Outdoor air pollution, in the forms of industrial smog, photochemical smog, acid deposition, and indoor air pollution, is a serious global problem. 2. Each year, at least 2.4 million people die prematurely from the effects of air pollution; indoor air pollution, primarily in less-developed countries, causes about two-thirds of these deaths. 3. We need to put our primary emphasis on preventing outdoor and indoor air pollution throughout the world. • The Asian Brown Cloud is a striking example of how bad air pollution can get. It results from large and dense populations of people relying mostly on fossil fuels for their energy, and wasting too many resources, rather than recycling and reusing products. It is an example of what can happen when people violate all of the principles of sustainability on a massive scale. • We can use these principles to help reduce air pollution. We can reduce inputs of conventional air pollutants into the atmosphere by relying more on direct and indirect forms of solar energy than on fossils fuels; reducing the waste of matter and energy resources and recycling and reusing matter resources; mimicking biodiversity by using a diversity of nonpolluting or low-polluting renewable energy resources; and reducing human population growth and wasteful resource consumption. A key strategy for solving air pollution problems is to focus on preventing or sharply reducing outdoor and indoor air pollution at global, regional, national, local, and individual levels. Critical Thinking The following are examples of the material that should be contained in possible student answers to the end of chapter Critical Thinking questions. They represent only a summary overview and serve to highlight the core concepts that are addressed in the text. It should be anticipated that the students will provide more in-depth and detailed responses to the questions depending on an individual instructor’s stated expectations. 1. The South Asian Brown Clouds (Core Case Study) exist mainly in southern and eastern Asia, and some people blame Asians for its existence. Others argue that their causes, as well as its effects, are global in nature. What is your position on this? Explain your reasoning. Answer: Answers will vary but should include some characterization of transport times and distances for pollutants. For many pollutants (particularly acid forms of N and S), the Asian brown cloud will be largely due to local emissions. For other compounds such as CO2 and to a lesser degree CO, the sources are more globally distributed. The South Asian Brown Clouds are a complex environmental issue with both regional and global dimensions. While the sources of the pollution primarily come from industrial activities, biomass burning, and vehicle emissions in southern and eastern Asia, the impacts are not confined to these regions. The pollutants can travel long distances, affecting air quality and climate globally. Blaming only the people in the affected regions oversimplifies the problem and ignores the broader, interconnected nature of global pollution. Addressing such issues requires international cooperation and collective action to mitigate the causes and manage the effects effectively. 2. Suppose someone tells you that carbon dioxide (CO2) should not be classified as an air pollutant because it is a natural chemical that is part of the carbon cycle (see Figure 3-19, p. 70) and a chemical that we add to the atmosphere every time we exhale. Explain the faulty reasoning in this statement about CO2. Answer: While carbon is a natural part of the carbon cycle, excess carbon is considered a pollutant because it effectively overloads the system, and cannot be adequately cycled. The build-up of carbon in the atmosphere then exacerbates the greenhouse effect and contributes to global climate change. 3. China relies on coal for two-thirds of its commercial energy usage, partly because the country has abundant supplies of this resource. Yet China’s coal burning has caused innumerable and growing problems for the country and for its neighboring nations. And now, because of the South Asian Brown Clouds (Core Case Study), for the Pacific Ocean and west coast of North America are experiencing pollution problems from this phenomenon. Do you think China is justified in developing this resource to the maximum, as other countries including the United States have done with their coal resources? Explain. What are China’s alternatives? Answer: This is a question with an answer that will vary by student perspectives. Core considerations are the equity issues involved in restriction of growth in developing countries versus the potential global impacts of emissions (particularly CO2) from coal fired power plants in China. Answers should recognize those complexities. China's extensive use of coal, while economically beneficial due to its abundant supply, is problematic due to severe environmental and health impacts both domestically and globally. The pollution from coal contributes to issues like the South Asian Brown Clouds, affecting regions far beyond China. While other countries have historically exploited coal, the contemporary context demands a shift towards more sustainable practices. China is justified in seeking energy security but should also explore cleaner alternatives. Potential alternatives include investing in renewable energy sources (solar, wind, hydro), improving energy efficiency, and developing cleaner technologies for coal use to mitigate environmental harm. 4. Photochemical smog is largely the result of motor vehicle emissions. Considering your use of motor vehicles, now and in the future, what are three ways in which you could reduce your contribution to photochemical smog? Answer: Reduce driving distances. Purchase lower emission vehicles (particularly partial zero emission vehicles). Change driving times to periods when air pollution is less of a problem. 5. Should the construction of tall smokestacks be banned in an effort to promote greater emphasis on preventing air pollution and acid deposition? Explain? Answer: Tall smokestacks help disperse pollutants, and so have one benefit of reducing the local impact of emissions. Given that many polluting facilities are located in underprivileged communities, there is some benefit to this (despite the larger justice question). Banning tall smokestacks could have the effect of causing larger local emissions and impacts, though the phrasing of the question suggests it might lead to other restrictions on emissions. If that were to occur, then there could be net positive benefits. 6. Explain how sulfur impurities in coal can lead to increased acidity in rainwater and to the subsequent depletion soil nutrients. Answer: The sulfur impurities, when burned, get released into the atmosphere as sulfur dioxide. During transportation by the wind this forms secondary pollutants such as sulfuric acid (H2SO4) and particles of acid-forming sulfate salts (SO42-). They stay in the atmosphere for 2–14 days, and during this time they can descend to the earth’s surface as either wet deposition (rain, snow, fog, and cloud vapor) with a pH less than 5.6, or dry deposition consisting of acidic particles. These acidic particles can decrease the pH of rain from its normal pH of 5.6 and fall as “acid rain”. 7. If you live in the United States, list three important ways in which your life would be different today if political action by U.S. citizens between the 1970s and 1990s had not led to the Clean Air Acts of 1970, 1977, and 1990, despite strong political opposition by the affected industries. List three important ways in which your life in the future might be different if such actions now do not lead now to the strengthening of the U.S. Clean Air Act or, if you do not live in the United States, to a similar law in the country where you reside. Answer: The Clean Air Acts established national ambient air quality standards (NAAQS), emission standards for hazardous air pollutants (HAPs), and authorized emissions trading for sulfur dioxide. Without these measures our lives would be affected adversely. Lead from the tailpipe emissions of vehicles run on leaded-gasoline would still be at high levels in the air. Chronic health effects from chemicals such as chlorinated hydrocarbons would be evident in more of the population. There would be greater amounts of SO2 in the air that would lead to more acid deposition affecting aquatic ecosystems and fish declines, cause buildings and other materials to be eroded at a faster rate, and lead to increased environmental degradation. We would also probably have increased respiratory diseases such as asthma with the greater amount of SO2. If not for the Clean Air Act lowering pollution emitted from new cars, there would be even more photochemical smog in the air. 8. List three ways in which you could apply Concept 18-6 to making your lifestyle more environmentally sustainable. Answer: Concept 18-6 suggests that there are ways to reduce air pollution through new technologies but that greater emphasis should be placed on pollution prevention. This idea means that a lifestyle could/should be adjusted to avoid emissions by such measures as avoiding travel or using mass transportation. Purchasing products that are made to limit air pollution (e.g., low VOC paints) and reducing other activities that cause air pollution can help. 9. Congratulations! You are in charge of the world. List your three most important strategies for dealing with the problems of (a) outdoor air pollution and (b) indoor air pollution. Answer: There are a number of possible answers. For outdoor air pollution, the answers should include methods to address tropospheric ozone pollution through NOx or VOC emission regulation, S pollution through clean(er) coal technologies, or alternative sources of energy (e.g. natural gas). For indoor air pollution, possibilities include requirements for home and building construction that limit VOC emission and requirements for monitoring Radon and CO concentrations. 1. Outdoor Air Pollution: • Enhance Regulations and Standards: Implement stricter emissions standards for industries and vehicles to reduce pollutants. • Promote Renewable Energy: Invest in and incentivize the use of clean energy sources to decrease reliance on fossil fuels. • Increase Green Spaces: Expand urban green areas and improve public transportation to lower pollution levels and enhance air quality. 2. Indoor Air Pollution: • Improve Ventilation: Ensure proper ventilation in buildings and homes to reduce indoor pollutant levels. • Use Clean Technologies: Promote the use of low-emission appliances and materials to minimize indoor pollutants. • Raise Awareness and Education: Educate the public about indoor air quality and effective practices for maintaining a healthy indoor environment. 10. List two questions that you would like to have answered as a result of reading this chapter. Answer: 1. What are the most effective technologies and strategies for reducing both outdoor and indoor air pollution on a large scale? 2. How can policies be designed to balance economic development with environmental protection, particularly in rapidly industrializing countries? Data Analysis Coal often contains sulfur (S) as an impurity that is released as gaseous SO2 during combustion and SO2 is one of six primary air pollutants monitored by the U.S. Environmental Protection Agency. The U.S. Clean Air Act limits sulfur emissions from large coal-fired boilers to 0.54 kilograms (1.2 pounds) of sulfur per million Btus of heat generated. (1 metric ton = 1,000 kilograms = 2,200 pounds = 1.1 ton; 1 kilogram = 2.20 pounds) 1. Given that coal used by electric power plants has a heating value of 27.5 million Btus per metric ton (25 million Btus per ton), determine the number of kilograms and pounds of coal needed to produce 1 million Btus of heat. 2. Assuming that all of the sulfur in the coal is released to the atmosphere during combustion, what maximum percent sulfur can the coal contain and still allow the utility to meet the standards of the Clean Air Act? 3. About 10,000 Btus of heat input are required for an electric utility to produce 1 kilowatt-hour (kwh) of electrical energy. How many metric tons (and how many tons) of coal must be supplied each hour to provide the input heat requirements for a 1,000-megawatt (1 million-kilowatt, or 106-kilowatt) power plant? 4. Assuming that this power plant uses coal with 1.00% sulfur and operates at full capacity 24 hours per day, how many metric tons and tons of sulfur will be released into the atmosphere each year? Answers: Solution Manual for Living in the Environment: Principles, Connections, and Solutions G. Tyler Miller, Scott Spoolman 9780538735346