I just can't get behind easing up on the pollution laws to allow more electric generators to be built. There are too many real tradeoffs.

http://www.boston.com/dailynews/163/nation/Study_finds_tiny_air_pollutant:.shtml

Study finds tiny air pollutants can trigger heart attack

By Lisa Falkenberg, Associated Press, 6/12/2001 01:09

DALLAS (AP) High levels of air pollution can trigger heart attacks in at-risk people exposed for even a short time, a study has found.

Researchers who interviewed 772 Boston-area patients about four days after their attacks found that the onset of symptoms correlated with times of high daily air pollution.

Tiny, invisible particles long have been thought to cause long-term cardiovascular diseases. The new study is the first to examine short-term effects on the heart, said senior author Dr. Murray Mittleman, director of cardiovascular epidemiology at Boston's Beth Israel Deaconess Medical Center.

The study of 489 men and 283 women, conducted from January 1995 to May 1996, defined at-risk people as obese, inactive or those with a history of heart problems.

The results appear in Tuesday's edition of Circulation, a journal of the American Heart Association.

The pollution particles are called PM-2.5, for particulate matter less than 2.5 micrometers in diameter. They're emitted by cars, power plants and industry, as well as fireplaces and wood-burning stoves.

Studies in the past five years have linked deaths and hospital admissions to a spike in PM-2.5 levels. In the study, risk for heart attack peaked two hours and 24 hours after patients were exposed to increased levels of the particles.

After two hours, risk increased 48 percent in the hours when pollution was the worst, compared to the best hours; after 24 hours, risk increased 62 percent.

The study also examined health risks caused by ozone, a chief ingredient of smog that's created when air pollutants mix. Ozone has been linked to lung and breathing problems, but researchers in this study found no data linking it to heart attacks, Mittleman said.

The study did not address how the particles trigger heart attacks. Other studies have shown that the particles, small enough to bypass the body's defenses and get into the lungs and other tissue, cause inflammation and blood clotting. These symptoms may contribute to heart attacks by blocking flow of blood through the heart, some researchers say.

Still other studies have shown that the particles may create electrical reactions that affect the nervous system.

PM-25 particles are light enough to travel long distances and infest air that's typically clean. Air conditioning helps to filter it out of the indoors.

''The best advice is to avoid outdoor activity on hot, hazy days,'' said study co-author Douglas Dockery, professor of environmental epidemiology at Harvard.

Researchers noted that Boston does not have excessive pollution and meets federal air quality standards, so the risk could be even worse in high-pollution cities such as Houston and Los Angeles.

The Environmental Protection Agency's air quality standards, last updated in 1997, have been challenged in court in part because no one has pinpointed why pollution particles pose a health risk.

The study could be used to encourage the EPA to consider stricter air standards, said Dr. Jonathan Samet, chairman of the department of epidemiology at Johns Hopkins University, who was not involved in the study.

-- Anonymous, June 12, 2001