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Smog's ozone: EPA wants more controls.

Smog's ozone: EPA wants more controls

While there is growing concern about the depletion of the beneficial stratospheric ozone layer, environment scientists are becoming increasingly wary of an overabundance of harmful, ground-level ozone. More than one-third of the U.S. population lives in areas that fail to meet the federal air-quality standard for ozone, a major constituent in urban smog, according to Lee M. Thomas, administrator of the Environmental Protection Agency (EPA). That's particularly troubling, he told a meeting of the Air Pollution Control Association in Minneapolis on Monday, because of new health effects data EPA has collected.

These data, from a variety of studies, indicate that even healthy individuals -- and especially those who exercise strenuously outdoors -- may be suffering adverse respiratory effects from concentrations of ozone at the current standard. Previously, policymakers had thought the current ozone standard provided a margin of safety even to those considered at increased risk, including people with emphysema, asthma and other chronic respiratory problems.

In urban air, ozone (O.sub.3.) forms when nitrogen oxides (from power plants and other sources) and hydrocarbons (from sources such as gasoline and paint thinner) rect with oxygen in the presence of sunlight. The chemical can lead to shortness of breath and aggravate existing respiratory disease. In animals, it has damaged lung tissue and increased susceptibility to infection. Ozone is not the only photochemically produced oxidant, but EPA has decided to focus on it as the primary irritant in smog -- the assumption being that reducing ozone production will simultaneously reduce the production of related photochemical oxidants.

The host of new human studies suggesting that some people may be suffering subtle adverse respiratory effects from exposure to ozone concentrations at 0.12 parts per million -- the level now allowed by EPA--is leading his agency to question whether its current standard is too high, Thomas says. The Clean Air Act requires not only that EPA base its primary ozone air-quality standard on health effects data, but also that this standard provide an adequate margin of safety to "protect the health of any (sensitive) group of the population."

Thomas sees the more critical problem for EPA right now, however, as what to do for the one-in-three people who live in what he refers to as "nonattainment" areas -- 32 major U.S. metropolitan regions that, after failing to meet the ozone air-quality standard in 1982, were given a five-year extension. Some areas should make the december 1987 deadline. Others won't be able to, Thomas says, "no matter how hard they try."

While open to suggestions on how to reduce urban ozone pollution, especially in chronic nonattainment areas, Thomas says he is now considering four basic approaches: forcing states to toughen enforcement of existing ozone-limiting procedures; instituting new control measures -- such as a limits on gasoline volatility or a requirement that new cars contain on-board gasoline-vapor-control systems; requiring that states outline how they plan to comply relatively soon--perhaps in three years; and developing a "sustained progress program" for those states with nonattainment areas well above the current standard that would require a succession of new steps be taken to continually reduce ozone levels over time.

David Doniger of Washington, D.C., a senior attorney with the Natural Resources Defense Council, calls Thomas's four-point strategy "disappointing." "We'd hoped for real action," he says, "not just talk about possible action." Requiring on-board controls for curbing gasoline vapors during car refueling has already been under discussion for two years, he says. And, he adds, the agency could have long ago designated the "stage two" vapor-control nozzles already standard on gas pumps in California and Washington, D.C., as a "reasonably available control technology." Such a designation would have made them all but mandatory in states having nonattainment areas, he points out. Finally, he says that if every state were made to assume the type of hydrocarbon-emissions control program used in California -- the state with the biggest problem--far fewer states would be out of compliance with the existing ozone standard today.

William Becker, executive director of the Washington, D.C.-based State and Territorial Air Pollution Program Administrators, agrees with Doniger on the gasoline vapor controls. Becker estimates that "about half a dozen states will make or not make their 1987 deadline based upon their ability to implement stage-two [gas pump] controls." Maryland is one state, he says, that was politically forced to back down on a planned requirement for these gas-pump controls when industrial leaders pointed out that the controls had not yet been designated as "reasonably available" by EPA.

In general, however, Becker says his group found the structure of Thomas's new ozone strategy sound. He adds that "there are a plethora of unresolved issues that will make or break this policy. But we got a commitment from the EPA staff [on June 23] that they will work with state and local air-pollution control officials to resolve them." One of the biggest of those issues is what to do about polluters whose hydrocarbon emissions cross state lines.
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Author:Raloff, Janet
Publication:Science News
Date:Jun 28, 1986
Words:833
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