By Eric Pianin
Washington Post Staff Writer
Wednesday, March 6, 2002; Page A01
Researchers for the first time have linked long-term exposure to fine particles of air pollution from coal-fired power plants, factories and diesel trucks to an increased risk of dying from lung cancer.
A study published in today's issue of the Journal of the American Medical Association concludes that people living in the most heavily polluted metropolitan areas have a 12 percent increased risk of dying of lung cancer than people in the least polluted areas. The study's authors said that exposure to the tiny particles of industrial emissions and sulfate pollutants is comparable to inhaling second-hand smoke from a cigarette.
The latest findings come as the Bush administration is considering proposals
for scaling back tough government legal action
against dozens of aging coal-fired power plants and refineries that violated the law by expanding without installing state of the
art anti-pollution equipment. Power plants built before 1980 generate about half the nation's electricity but nearly all of the utility industry's unhealthy sulfur dioxide, nitrogen oxide and soot, experts said. Environmental groups seized on the new findings as support for their position that tough enforcement was still needed.
Air pollution levels have declined significantly during the past 20
years because of stepped-up enforcement of clean air laws, yet
levels of fine particle emissions in New York, Los Angeles, Chicago and Washington are at or exceed limits set by the Environmental Protection Agency.
Fine particles are compounds and pollutants produced through combustion in power plants, refineries, diesel trucks and buses. They are so tiny – smaller than 2.5 microns or a fraction of the thickness of a human hair – that they evade the human lung's natural defenses and are inhaled deeply.
Previous research by Harvard University and the American Cancer Society
strongly linked these fine particles to high mortality
rates from cardiopulmonary diseases such as heart attacks, strokes and asthma. Until now, however, scientists lacked sufficient
statistical evidence to directly link those emissions to elevated lung cancer death rates.
By gathering air pollution data and 16 years of personal health records
of 500,000 of the people who had participated in the
earlier American Cancer Society study, scientists amassed the "statistical fire power" to finally make that connection, said
Bringham Young University epidemiologist Arden Pope, a chief author of the study.
Allen Dearry, a scientist at the National Institute of Environmental
Health Sciences, which partly funded the study, called it "the
best epidemiologic evidence that we have so far that that type of exposure is associated with lung cancer death."
Environmentalists, public health advocates and citizens groups contend
that power plant emissions are among the worst
contributors to the lung and heart disease problems highlighted by the new study. Brian P. Urbaszewski, director of
environmental health programs for the American Lung Association of Metropolitan Chicago, said the study "is another nail in
the coffin for these old coal-fired power plants."
However, industry officials contend that the link between power plant
emissions and the elevated mortality rates is not all that
clear, and that there are limits to how much utilities can spend on anti-pollution measures and remain competitive.
"We as an industry have dramatically reduced emissions, and more reductions
will be made because they are required under
existing regulations," said Jayne Brady, a spokesperson for the Edison Electric Institute, a utility group. Brady added that the
new cancer study is just "one of many studies."
An EPA spokesman said the agency was "interested" in the new findings but that officials have not fully assessed it yet.
The scientific and legal controversy over the health effects of fine
particle emissions has raged for years, culminating in the
EPA's decision in 1997 to issue tough new standards limiting the annual average level of fine particles in the air to 15
micrograms per cubic meter. The Supreme Court upheld the standards in February 2001, but then remanded them to a lower
court for further consideration.
The landmark studies published by Harvard researchers in 1993 and the
American Cancer Society in 1995 documented a high
incidence of premature deaths among people chronically exposed to fine particle emissions.
Nationwide, as many as 30,100 deaths a year are related to power plant
emissions, according to a study by Abt Associates, a
private research organization that does work for the EPA. By comparison, 16,000 Americans are killed each year in drunken
driving accidents, and more than 17,000 are victims of homicides.
Industry officials and some scientists have disputed these findings
and argued that the past research failed to account for many
variables, such as regional disparities and an individual's occupation and diet.
The newly released study – conducted by Pope, George Thurston, professor
of environmental medicine at New York
University's School of Medicine, and Daniel Krewski of the University of Ottawa – sought to address the criticism in doing
follow-up studies of a half-million people living in 100 cities throughout the country.
The researchers first took into account other risk factors for heart
and lung disease such as cigarettes, diet, weight and
Lung cancer death rates were compared with average pollution levels,
as measured in micrograms per cubic meter of air. The
researchers found that the number of lung cancer deaths increased 8 percent for every increase of 10 micrograms. Other heart-
and lung-related causes of death increased 6 percent for every 10 microgram increase.
At the study's inception in 1982, the most polluted cities had fine
particulate pollution levels about 20 micrograms per cubic
meter higher than the least polluted cities. As a result, residents in the most polluted cities had an approximately 16 percent
excess risk of dying from lung cancer due to fine particulate air pollution, the study shows. By the end of the study in 1998, the
air had become somewhat cleaner, reducing that risk, but it remained 12 percent higher in the worst polluted areas, the authors
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