Update on air quality issues
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Richard M. Dowd
In recent years, air quality issues have been centered on new concerns, such as toxic air pollutants and carcinogenicity. However, several traditional issues have reemerged in recent months, and action appears imminent in two contrcversial areas: the bubble policy and acid rain.
The bubble revisited In essence, the bubble policy devised by EPA treats all emissions from different points within a facility as if they originated under a single enclosed dome o r bubble; facility operators are allowed to reduce selected emissions within that bubble to meet one overall emission limit for the facility. Since the US. Supreme Court decision of June 1984 affirming EPA‘s discretion to allow certain applications of the bubble policy within air quality control regions (AQCRs) designated as nonattainment (areas not achieving national ambient air quality standards), there has been controversy within and outside the agency about the extent of the policy’s applicability. Recent dispute has revolved around the issue of banking-allowing emission reductions to be applied as credits in subsequent permit applications for new facilities or for modifications to existing sources. Early indications are that EPA will allow banking-for use, trades, or outright sale of emission reduction credits-in nonattainment AQCRs under certain circumstances. Banking of emission reductions is likely to be allowed, provided that there is a 20% reduction in overall emissions after application of the credit. In particular, it appears that reductions attributable to facility or process shutdowns will be eligible for banking credit if one of three condition; prevails: M)13.936W86/09200659$01.5010
application for a new or modified source had been made prior to the shutdown, the shutdown occurred before the adoption of the bubble policy, o r the credit is otherwise allowed through a state-approved banking program. There are also circumstances under which EPA will allow the banking credit even if the shutdown occurred for nonenvironmental reasons such as economic problems. As with all issues associated with the bubble policy, this decision is likely to encounter continuing controversy.
ozone on highly sensitive individuals, such as asthmatics. At present, the standard is designed to protect exercising adults. Some CASAC members believe that, as more research is done, quite possibly the level at which adverse effects on people can be measured will be lower than has been substantiated to date. No new studies, however, have been presented to support a more stringent standard. Any tightening of the standard would have significant implications for attainment of air quality standards in many parts of the country.
Acid rain bill The House Energy and Commerce Subcommittee on Health and Environment, chaired by Henry Waxman (D-Cal.), has reported its first bill to control acid rain. The bill, with bipartisan sponsorship, proposes a IO-million Uyr reduction in annual SO2 emissions and a 4-million Uyr reduction in NO., emissions by 1997, with 1980 as the base year for measuring reduction levels. The bill phases the reductions in two stages: Half will be made by 1993 and the remainder by 1997. It also contains compensation provisions to distribute any resulting cost increases equitably among electric utility users. The bill would authorize the states to identify suitable control strategies and plans. If a state did not comply, federal standards would take effect.
In the wake of recent intensive efforts to deal with acid rain, study results have been slowly forthcoming, led several years ago by West German research linking forest damage to acid deposition. New US. studies indicate that the issue may be more complicated than theories had indicated. In particular, ozone is implicated, as well as the previously suspect sulfur and nitrogen oxides. Although this is not surprising because there is evidence that ozone affects agricultural crops, new evidence shows increasing damage to pine forests in the East; perhaps this damage is due to a combination of sulfur oxides and ozone. The theory currently commanding the most support hypothesizes that acid deposition leaches nutrients from the soil; ozone then furfher weakens the trees, allowing natural enemies such as insects greater scope to kill them. Mitigation has been achieved in some cases by adding nutrients to the soil directly around trees (fertilizing), but fertilizing one tree is a far different job than fertilizing an entire forest. These traditional issues have resurfaced, but the current focus on them does not lessen concerns about control of hazardous air pollutants and other toxic wastes. New issues-such as incineration-associated with EPA’s implementation of the congressionally mandated land disposal ban are likely to dominate in coming months.
Meeting on OzOne In April, EPA’s Clean Air Science Advisory Committee (CASAC) met with agency staff to discuss the revised ozone criteria document and accompanying staff paper. CASAC raised questions regarding the ozone standard itself and suggested that EPA may find it desirable to reduce the present 0.12-parts per million one-hour standard to a more stringent level. Although CASAC made no specific recommendations, members expressed concern about the potential for adverse health effects at even lower levels. There seemed to be no support for relaxing the standard. This touches on an issue-that has been central to the ozone debate for at least 10 years: the effect of
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Forest damage
Richard M. Do&, Ph.D., is a Washi n ~ l o n ,D.C., consultanr to Emironmental Research & ~ c h n o ~ oInc. ~y, Environ. Sci. Technol.. Vol. 20. NO. 7. 1986
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