Environmental Problems, Their Causes, and Sustainability 1

PreventionMass transitBicycles andwalkingLess pollutingenginesLess polluting fuelsImprove fuel efficiencyGet older, pollutingcars off the roadGive buyers large taxwrite-offs for buyinglow-polluting, energyefficientvehiclesSolutionsMotor Vehicle Air PollutionRestrict driving in polluted areasCleanupEmission controldevicesCar exhaustinspections twicea yearStricter emissionstandardsFigure 20-19 Solutions: methods for reducing emissions frommotor vehicles.What Should We Do about UltrafineParticles? Another ControversyThere is controversy over reducing emissionsof ultrafine particles that pose a serious threat tohuman health.Research indicates that invisible particles—especiallyfine particles with diameters less than 10 microns(PM-10) and ultrafine particles with diameters less than2.5 microns (PM-2.5)—pose a significant health hazard.Such particles come from a variety of sources (Figure20-6).They are not effectively captured by most air pollutioncontrol equipment and are small enough to penetratethe respiratory system’s natural defenses againstair pollution. They can also bring with them dropletsor other particles of toxic or cancer-causing pollutantsthat become attached to their surfaces.Once they are lodged deep within the lungs, thesefine particles can cause chronic irritation that can triggerasthma attacks, aggravate other lung diseases, andcause lung cancer. These lung problems interfere withthe blood’s uptake of oxygen and release of CO 2 ,which strains the heart and increases the risk of deathfrom heart disease. According to several recent studiesof air pollution in U.S. cities, fine and ultrafine particlesprematurely kill 65,000–200,000 Americans eachyear.Exposure to particulate air pollution is much worsein most developing countries, where urban air qualityhas generally deteriorated. The World Bank estimatesthat reducing particulate levels globally to WHO guidelineswould prevent 300,000–700,000 premature deathsper year!In 1997, the EPA announced stricter emission standardsfor ultrafine particles in the United States. TheEPA estimates the cost of implementing the standardsat $7 billion per year, with the resulting health andother benefits estimated at $120 billion per year.According to industry officials, the new standardis based on flimsy scientific evidence and its implementationwill cost $200 billion per year. EPA officialssay that their review of the scientific evidence—one ofthe most exhaustive reviews ever undertaken by theagency—supports the need for the new standard forultrafine particles. Furthermore, a 2000 study by theHealth Effects Institute of 90 large American cities supportedthe link between fine and ultrafine particlesand higher rates of death and disease. Industries affectedby these new standards are lobbying Congressto have them weakened or overturned or to extenddeadlines for their implementation.xHOW WOULD YOU VOTE? Do you support establishinga stricter standard for emissions of ultrafine particles? Castyour vote online at http://biology.brookscole.com/miller14.How Can We Reduce Indoor Air Pollution?Emphasize PreventionLittle effort has been spent on reducing indoor airpollution even though it is a much greater threat tohuman health than outdoor air pollution.Reducing indoor air pollution does not require settingindoor air quality standards and monitoring the morethan 100 million homes and buildings in the UnitedStates (or the buildings in any country). Instead, airpollution experts suggest several ways to prevent orreduce indoor air pollution (Figure 20-20). Anotherpossibility for cleaner indoor air in some high-risebuildings is rooftop greenhouses through which buildingair can be circulated.In developing countries, indoor air pollution fromopen fires and leaky and inefficient stoves that burnwood, charcoal, or coal could be reduced if governmentsgave people inexpensive clay or metal stoves,which burn biofuels more efficiently while ventingtheir exhaust to the outside, or stoves that use solar energyto cook food (solar cookers) in sunny areas. Doingthis would also reduce deforestation by using less fuelwoodand charcoal.458 CHAPTER 20 Air Pollution