14. AIR POLLUTION: Soot exposure significantly increases death risk -- study (06/03/2009)

Robin Bravender, E&E reporter

People exposed to airborne soot pollution are nearly twice as likely to die from heart disease as previously thought, according to a study released today.

The Health Effects Institute study found that for each 10-micrograms-per-cubic-meter increase of exposure to airborne soot, or fine particle pollution, there is a 13 percent increase in risk of premature death from all types of cardiopulmonary disease and a 24 percent increase in the risk of premature death from ischemic heart disease.

Ischemic heart disease reduces blood supply to the heart and can lead to heart attacks. It is one of the leading causes of death in the United States.

The findings show that the risk of mortality from soot exposure is nearly double what was previously thought. Previous studies had shown a 7 percent to 8 percent increase in deaths from all types of cardiopulmonary disease and about a 12 percent to 15 percent increase in deaths from ischemic heart disease, said Dan Greenbaum, president of the Health Effects Institute, an independent research organization funded jointly by U.S. EPA and industry.

"This would strengthen the case that [particulate matter] is a serious health risk," Greenbaum said.

The study tracked 360,000 people over the age of 18 between 1992 and 2000 as part of an ongoing study of mortality. The study has played a central role in setting federal standards for fine particulate matter pollution in the United States. The research was conducted by a team led by Daniel Krewski of the University of Ottawa and funded by the institute.

"It is the most extensive and detailed analysis of that cohort that we've seen today," Greenbaum said.

Researchers also found that there may be significant differences in how these health effects occur nationwide. Scientists found similarly elevated risks of ischemic heart disease in both Los Angeles and New York but found that people in Los Angeles faced higher risk levels for other causes of death.

The study could play a major role in determining federal limits on particle pollution as EPA reviews the national limits on airborne soot.

A federal appeals court sent the Bush administration's 2006 soot standards back to EPA for review in February after determining that the agency had failed to adequately explain why an annual level of 15 micrograms per cubic meter is sufficient to protect public health (Greenwire, Feb. 24).