The Cancer In the Air We Breathe
Washington area health experts and regional transportation specialists seeking changes in environmental quality are seizing on a recently published study that shows local residents face an above-average risk of contracting lung cancer from fine particles
Despite improvements in some measures of local air quality over the last two decades, the study showed fine-particle pollution from power plants, industrial emissions and diesel engines severe enough to increase disease risk. It compared the effects of this kind of pollution with second-hand cigarette smoke.
"[The study] adds urgency," said D.C. Council member Phil Mendelson (D-At Large), chairman of the region's Transportation Planning Board, which votes on all road and transit projects and makes sure they conform to pollution limits. "The different governments [in the Washington area] are still unenthusiastic about finding the dollars, because clean air costs" a lot, he said.
Agreed George Thurston, professor of environmental medicine at the New York University School of Medicine and co-author of the study, "We've made a lot of progress, but we still have a long way to go."
The study, which appeared in the Journal of the American Medical Association (JAMA), provides the first definitive link between cancer risk and extended exposure to fine particles of pollution from power plants and diesel engines. Previous studies had made similar links, but with less data gathered over a shorter period of time.
While the study's authors emphasized in interviews that their research wasn't aimed at assessing health risks for residents of specific cities, Washington area residents, as part of the polluted Northeast corridor, face significantly higher cancer risk from pollution than those living in most rural areas.
The findings may help to explain why doctors in recent decades have been seeing more cases of lung cancer in nonsmokers, said Paul Y. Song, a radiation oncologist for Inova Fairfax Hospital and a member of the board of directors of the Washington-area chapter of the American Cancer Society. "In the past almost everyone you ever saw with lung cancer was a smoker," said Song, who called the link shown by the JAMA study "alarming."
But so far such reports are largely anecdotal; lung cancer mortality figures reflect too many possible contributing factors to be viewed as a measure of air quality. According to data collected by the Centers for Disease Control and Prevention and assembled by the American Cancer Society, the rate of deaths from lung cancer in Washington, Maryland and Virginia is higher than the national average. Of the three jurisdictions, Maryland has the highest lung cancer mortality rate, averaging an annual 52.9 deaths per 100,000 people over the period 1994 through 1998. The District's rate is 51.7, and Virginia's is 52. The national average is 48.8.
Because smoking is a greater risk factor for lung cancer and because rural areas tend to have more heavy smokers, disease incidence data -- the number of new cases per year -- also don't correlate with the pollution study findings.
In the Washington region, some rural or semi-rural areas show higher incidence rates than more urban areas. In mostly rural Charles County, for example, 59.3 people per 100,000 were diagnosed with lung cancer in 1999, compared with 39.2 in Montgomery County, according to the Maryland Cancer Registry. In Virginia, 54.2 new cases of lung cancer per 100,000 people were diagnosed in a rural part of Shenandoah County in 1998, significantly more than in Fairfax (34.3) or Alexandria (30.9), according to the Virginia Cancer Registry.
The Washington area is not, and has never been, as industrialized as Baltimore or New York, where measures of particulate matter have historically been higher. But there are about two dozen power plants within 100 miles of Washington, about evenly split in numbers between Maryland and Virginia. Applications to build nearly a dozen more are being reviewed by Maryland and Virginia officials, according to the Metropolitan Washington Council of Governments (COG).
People who live within 25 to 30 miles of coal-burning power plants -- generally the most polluting type of facility -- appear to be at greatest risk for exposure to particulates, Thurston said. For example, measurements of fine-particle pollution in Charleston and Huntington, W.Va., both in coal-mining country, near several coal-burning plants and in an area heavy in chemical manufacturing, show levels comparable to those in New York, Thurston said.
Reducing exposure is difficult -- or impossible -- since fine-particle pollution is in the air. The only way to improve conditions is to reduce the overall quantity of the stuff in the air -- something determined by national, regional and corporate policies. "[The study] makes it clear that since much of the pollution we're talking about is caused by fossil fuel combustion, energy policy is really also environmental and health policy," Thurston said.
Measurements of fine-particle pollution in the Washington regiongenerally show that the District's urban core has slightly higher readings than the suburbs, said David Krask, chief of technical services for the D.C. Air Quality Division.
Industry officials responding to the study called the link between power plant emissions and disease risk less clear than the researchers saw it, and said that further anti-pollution measures beyond those already planned would hurt their competitiveness.
"What this study is calling for is already happening," said Dan Genest, a spokesman for Dominion Virginia, which provides electricity to about 850,000 Washington area customers.
Genest said Dominion Virginia had already made major reductions in emissions and is in the process of installing new technologies to further reduce pollutants. At the company's Mount Storm power plant, a coal-burning plant about 100 miles west of Washington in West Virginia, $120 million worth of new pollution-reduction equipment will reduce sulfur dioxide emissions by 95 percent this year, Genest said. Similar technology is being installed at three of the company's other coal-burning plants, with reductions in nitrogen oxide projected to be around 80 percent, Genest said.
Joan Rohlfs, chief of air quality planning for COG, said that the council's staff has only recently begun tracking fine-particle pollution and that it will be some time before they can say whether Washington is in compliance with 1997 federal guidelines, limiting such emissions to 15 micrograms per cubic meter.
Of more concern traditionally in the Washington region, she said, have been ozone precursors like carbon monoxide, which come from many sources, including automobiles. In the area of ozone pollution, the Washington metro area has for years been considered an EPA "non-attainment area," meaning ozone levels exceed government standards. The region was required to meet such standards by 1999, but failed and was granted an extension to 2005.
Diesel-engine pollution, also linked to lung cancer by the JAMA study, has been a primary focus for regional planners.
The JAMA study concluded that people living in heavily polluted areas, such as Chicago, Los Angeles and Washington, have a 12 percent greater risk of dying from lung cancer than people in the least polluted cities, such as Billings, Mont., and Bismarck, N.D.
The cancer link, made in earlier studies but never so comprehensively as in the JAMA study, comes at a time when local clean-air advocates have been seeking incentives to switch diesel trucks and buses to cleaner forms of fuel and local government efforts have been hampered by tight budgets.
Late last month, members of the Transportation Planning Board, which includes representatives from local governments in the District, Maryland and Virginia, said they would likely have to delay new pollution-cutting measures because of budget constraints. But after a surprise announcement by Maryland Gov. Parris N. Glendening (D), the board unanimously voted to adopt stricter and more costly anti-pollution measures. Maryland officials have yet not indicated how much money they will provide for the new regional programs, which could include replacing taxis and buses with vehicles that run on cleaner fuel, encouraging people to use public transit and replacing engines on heavy diesel trucks.
Nationally, the Bush administration is adopting rule changes to discourage government lawsuits against dozens of coal-fired plants that violated the law in recent years by expanding without installing new anti-pollution devices.
The JAMA study gathered EPA air pollution data and 16 years of personal health records of 500,000 people. Earlier research by Harvard University (1993) and the American Cancer Society (1995) examined the health impact of fine-particle pollution over a shorter period of time.