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Breathing Easier: Chemistry Professor Studies Ways to Lower Air Pollution...continued
Los Angeles is now understood to be the textbook "tailpipe" case, because automobiles are largely responsible for both the hydrocarbon and nitrogen oxide emissions that lead to elevated levels of ozone. Air quality has been significantly improved in that area over the past 30 years by attention to reducing tailpipe emissions of hydrocarbons and nitrogen oxides. More fuel-efficient engines, cleaner fuels, and catalytic converter technology have been successfully implemented to reduce the number of unhealthy days due to smog by over 50 percent. However, the Los Angeles recipe for improved air quality has not proven as successful in other locales. For example, a recent study of Houston’s air quality problems came to the conclusion that hydrocarbon emissions from the world’s largest concentration of petrochemical plants are largely to blame for the problem there. Therefore, the scientific evidence suggests that stricter emission controls for automobiles probably would not be a cost-effective way of improving air quality in Houston, whereas limits on emissions from oil refineries would likely be effective. Similarly, a recent study of Atlanta’s smog problems concluded that the presence of deciduous forests (a source of the hydrocarbon isoprene) around the city exacerbates the ozone-producing propensity of the atmosphere. Because it is not desirable to remove the forests, the scientific recommendation is to take aggressive measures to limit emissions of the other ozone producing ingredient, the nitrogen oxides, from all sources, tailpipe or otherwise. Therefore, these particular cases show that a detailed understanding of the chemical mechanisms responsible for ozone formation must inform policy decisions if they are to be effective and economical.
It is also important to recognize the political factors that play a role in the implementation of strategies to improve air quality. It is particularly significant to note that while the CAA provides for uniform national standards, the implementation and enforcement of any pollution abatement strategy lies with the states. The political strength of the environmental movement in California has always pushed that state to enforce stricter standards than that required by the federal CAA. Indeed, because of California’s influence, air quality is probably better nationwide as technologies developed to comply with strict California policies have been implemented across the country. However, in both the Houston and Atlanta cases, presumably because of the lesser political influence of environmental issues in these areas as compared to California, officials have only begun to implement new policies designed to lower smog levels after years of violating the CAA. Even now, these policies were formulated at the point of a gun; the U.S. EPA had threatened to carry out the "death penalty" provision of the CAA--revocation of federal highway funds--if strong action had not been taken in those cities. And, of course, the U.S. EPA itself is subject to political forces. Currently, the CAA necessitates a process called New Source Review (NSR), which requires that any new or upgraded power plant install the most technologically advanced (and expensive) emissions control technology. The utility industry argues that this policy discourages the building of new power plants, and encourages the continued operation of older, dirtier power plants. The Bush administration agrees with this conclusion, and has taken steps to make the NSR aspect of the CAA much more lenient. Many states that are already struggling to comply with the CAA are downwind of many of the power plants that would be subject to the less stringent emission standards. Undoubtedly, the resolution of this issue will be litigiously complex.
In summary, there have been some notable successes in the effort to improve air quality, particularly with respect to the acute smog episodes common to America’s large cities, thanks to a large-scale effort to understand and monitor the chemical processes of the atmosphere coupled with effective public policy decisions. Therefore, many urban areas have experienced an improvement in air quality since the CAA was enacted. However, at the same time, air quality has decreased in many less urbanized locales due to emissions that are transported across municipal, state, and even national boundaries. These issues are complex from a purely scientific level and much research, such as that described in this article, is currently being performed to address this problem. The issues are even more complex on a public policy level because the CAA does not provide for coordinated action above the state level--most interstate pollution issues are now settled in federal court. Nonetheless, if as much scientific and policy progress is made in the next 30 years as has been made in the past 30 years, we might all be breathing easier in the future.
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