One tranquil night in June, the air pollution monitors at Shenandoah National Park registered a swift and curious spike in smog, and the trouble wasn't coming from the sanctuary's abundant trees and wildlife.
The pollutants were blowing in from the Midwest, wafting toward the East Coast and along the way tripping air-quality monitors in pristine refuges and threatening worse concentrations in cities. For the Washington area, it was the start of the worst stretch of ozone pollution this summer.
Between June 24 and June 26, when air-quality regulators tracked the movement of a mass of ozone-laden air across the eastern United States, smog monitors from Annandale to western Prince George's County recorded levels in excess of federal health limits.
"We got a lot of bad air from the Ohio River Valley," said Charles Piety, a University of Maryland meteorologist who studies these flows for the state. "It was our standard high-ozone meteorology."
Although the Washington area's infamous traffic and the popularity of SUVs often are blamed for the region's smog problems, which were classified as "severe" by federal officials this year, a significant source of the area's pollution lies beyond local control. Some scientists say that half and sometimes more of the offending ozone is from out of town. And as the pollution monitors at Shenandoah show, it's arriving in concentrations high enough to violate federal health limits even without a boost from local emissions.
Regardless of the ozone's origins, such episodes have dramatic local consequences beyond the breathing woes of asthmatics and others with lung ailments.
Washington's late-June ozone episode could, in fact, prove both critical and costly: To comply with federal air-quality regulations by 2005, the region is allowed three days for any one monitor to pick up an ozone "exceedance."
The June incident set off one local monitor on two days, meaning that just one more exceedance is allowed at that site for the next 21/2 years.
Area leaders will meet this week to consider another plan to reduce local emissions in hopes of coming into compliance with federal regulations. The costs to businesses, consumers and governments of the existing and new measures, which include reformulated gasoline and new kinds of paint, have not been calculated precisely. But they will run at least into the tens of millions of dollars annually, officials say.
"There is a significant equity issue here," said Joan Rohlfs, chief of air-quality planning at the Metropolitan Washington Council of Governments, which coordinates area pollution plans. "Some say it's just a local problem. But you have to look at the bigger picture, too."
Jeff Clark, director of policy for the Environmental Protection Agency's air-quality office, said: "Ultimately, we may need a congressional fix to better address this long-range ozone transport. But we've been doing everything we can in the meantime to cut regional emissions that cause the problem."
Clark cited the agency's work toward cleaner cars and fuels and regulations to take effect next year that limit summertime emissions from power plants across the eastern part of the country. "The downwind people tend to point fingers at the upwind people and vice versa. What we're trying to do is get both sides to achieve the needed emissions reductions," he said.
The quandary over enforcement stems at least partly from scientific uncertainty. Researchers long have sought to quantify the amount of ozone transported from one region to another. Modeling experiments cited by the EPA in the late 1990s suggested that during four ozone episodes in Washington, the proportion of out-of-state ozone was about 24 percent.
Local leaders have reported that the predominant cause of the region's smog is local emissions, and they have issued warnings about the proliferation of commuter traffic, SUVs in particular. During a code red ozone alert, people are discouraged from unnecessary driving or refueling before dark.
"It varies from episode to episode, but the problems are coming from our cars, trucks and SUVs, and we are not doing everything that we can be doing to reduce the ozone levels," said Michael Replogle, who monitors the issue for the advocacy group Environmental Defense.
Research by a team at the University of Maryland suggests that experiments in the 1990s overestimated the role of local emissions. The estimates were based on complicated models of meteorology and atmospheric chemistry.
But actual air samples taken more recently by researchers in flight, both upwind and downwind during ozone episodes, suggested that during a typical episode, about half of the man-made pollution, and in some cases more, came from out of town.
In addition, a critical flaw was discovered in the old models. They assumed that, for the most part, ozone from the Midwest was not traveling across the Appalachians. But it was.
"We knew they were wrong, based on our airplane flights," said Jeff Stehr, a research scientist at Maryland. "The models were not capturing it at all."
Given the updated science, exactly how ozone emissions should be regulated is a matter of continuing debate.
Environmentalists and some local officials continue to raise concerns about older, dirtier power plants operating in the Midwest.
Emissions restrictions taking effect next year across a multi-state region are expected to reduce the effects on Washington and elsewhere, however. And in what some hailed as a key precedent for environmentalists, a federal judge on Thursday ruled that FirstEnergy's Ohio Edison Co. violated clean-air laws by renovating seven aging coal-fired power plants without installing anti-pollution equipment.
Some, such as D.C. Council member Phil Mendelson (D-At Large), who heads the region's air-quality committee, argue that the matter of ozone transport is beside the point: Even if Washington is being held accountable for out-of-town smog, he said, federal officials have been too lenient.
"The federal system is not being hard enough on us," Mendelson said. "Ozone transport is an issue, but so are our own emissions. If we weren't putting up as much gas as we do, we wouldn't be arguing about the transport."
Moreover, people on both sides note, Washington's emissions often blow into cities downwind, so who are Washingtonians to complain?
"We are a major source of pollution for the tens of millions of people who live downwind of us," Replogle said. "We should be careful about using this argument lest others use it against us. We're all in this together."
To many, a regulation system that holds individual regions accountable for a problem that spans borders seems out of balance.
"Whatever we in the Washington region commit to doing about ozone, we are only addressing half the problem, and that's unacceptable," said Fairfax Supervisor T. Dana Kauffman (D-Lee), who serves on the region's air-quality committee. "Unfortunately, air pollution doesn't recognize state boundaries. Ohio's profit is our problem."
source: http://www.washingtonpost.com/ac2/wp-dyn/A39491-2003Aug9?language=printer 10aug03
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