Environmental Problems, Their Causes, and Sustainability 1

How Many People Die Prematurely fromAir Pollution? A Major KillerEach year air pollution prematurely kills about3 million people, mostly from indoor air pollutionin developing countries.Table 20-2 lists some of the harmful health effects ofprolonged or chronic exposure to six major air pollutants.According to the World Health Organization,worldwide at least 3 million people (most of them inAsia) die prematurely each year from the effects of airpollution—an average of 8,200 deaths per day. About2.8 million of these deaths (93%) are from indoor airpollution, mostly from burning wood or coal insidedwellings in developing countries. This explains whythe World Health Organization and the World Bank considerindoor air pollution one of the world’s most serious environmentalproblems.In the United States, the EPA estimates that annualdeaths related to indoor and outdoor air pollutionrange from 150,000 to 350,000 people—equivalent toone to two fully loaded 400-passenger jumbo jetscrashing each day with no survivors. Millions more becomeill and lose work time. Most of these deaths arerelated to inhalation of fine and ultrafine particulatesin indoor air.According to recent studies by the EPA, each yearmore than 125,000 Americans get cancer from breathingsoot-laden diesel fumes from buses, trucks, tractors,bulldozers and other construction equipment,and portable generators. The EPA says that in one yeara large diesel-powered bulldozer produces as much airpollution as 26 cars.The EPA has proposed emission standards fordiesel-powered vehicles that become effective in 2007with full compliance by 2012. The EPA estimates thatthese standards should reduce diesel-fuel emissionsby more than 90% and prevent as many as 12,000 prematuredeaths. Manufacturers of diesel-powered enginesand vehicles dispute the EPA findings and hopeto relax or delay the standards. Environmentalists contendthat the standards will encourage the use of hybriddiesel-electric buses or better buses and otherlarge vehicles powered by natural gas.20-7 PREVENTING AND REDUCINGAIR POLLUTIONHow Have Laws Helped Reduce Air Pollutionin the United States? Clean Air Acts to theRescueClean Air Acts in the United States have greatlyreduced outdoor air pollution from six majorpollutants.The U.S. Congress passed Clean Air Acts in 1970,1977, and 1990. With these laws the federal governmentestablished air pollution regulations for key pollutantsthat are enforced by each state and by majorcities.Congress directed the EPA to establish nationalambient air quality standards (NAAQS) for six outdoorcriteria pollutants (Table 20-2). The EPA regulatesthese chemicals by using criteria developed from riskassessment methods to set maximum permissible levelsin outdoor air.One limit, called a primary standard, is set to protecthuman health, and another, called a secondary standard,is intended to prevent environmental and propertydamage. Each standard specifies the maximum allowablelevel, averaged over a specific period, for a certainpollutant in outdoor (ambient) air. The EPA has alsoestablished national emission standards for more than188 hazardous air pollutants (HAPs) that may cause serioushealth and ecological effects. These chemicals includeneurotoxins, carcinogens, mutagens, teratogens, endocrinesystem disrupters, and other toxic compounds(Section 19-3, p. 416). Most of these chemicals are chlorinatedhydrocarbons, volatile organic compounds, orcompounds of toxic metals.Measurements of HAPs in outdoor air are made inabout 50 locations in the United States. One of the bestsources of information about these chemicals in yourlocal area is the annual Toxic Release Inventory (TRI) collectedand released to the public as part of communityright to know laws enacted by Congress in 1986. ThisTRI law requires 23,000 refineries, power plants, hardrock mines, chemical manufacturers, and factories toreport their releases above certain minimum amountsand their waste management methods for 667 toxicchemicals.Great news. According to a 2003 EPA report, combinedemissions of the six criteria air pollutantsdecreased by 48% between 1970 and 2002 even withsignificant increases in gross domestic product, vehiclemiles traveled, energy consumption, and population.Also, between 1983 and 2002, emissions of each ofthe six major outdoor air pollutants decreased—by93% for lead, 41% for carbon monoxide, 40% for volatileorganic compounds (VOCs), 34% for suspendedparticulate matter with a diameter less than 10 microns(PM-10), 33% for sulfur dioxide, and 15% forNO x . During this same period the ground-level atmosphericconcentration for ozone averaged over 8 hoursdecreased by 14%. Between 1983 and 2002, the averageatmospheric concentration of very fine suspended particulatematter with a diameter less than 2.5 microns(PM-2.5) decreased by 8%. And nationwide emissionsof toxic chemicals into the air dropped by about 21%between 1990 and 1999.However, releases of two HAPs—mercury anddioxins which are toxic at very low levels—have increasedin recent years. According to the EPA, about100 million Americans live in areas where the estimatedhttp://biology.brookscole.com/miller14453