Hospitals see effects of spikes in pollutionMar 8, 2006 | Chicago Sun Times
When the air is filled with increased levels of soot and other tiny particles, more people end up in the hospital with heart and lung problems, according to the largest study yet on the health effects of such pollutants.
Published today in the Journal of the American Medical Association, the nationwide study of 11.5 million Medicare enrollees is the latest in a growing body of research linking cardiovascular and respiratory diseases with exposure to fine "particulate matter" known as PM 2.5.
Particulate matter has become a hot-button issue with the U.S. Environmental Protection Agency, which is in the midst of revising its standards for the pollutant. The agency has proposed reducing how much PM 2.5 could be in the air on a daily basis, but environmental groups say the revised standards don't go far enough to protect public health. The EPA will hold a public hearing on the matter at 9 a.m. today in Chicago at the Hyatt Regency, 151 E. Wacker.
PM 2.5 PRIMER
WHAT IS IT?
Particulate matter, or PM, is the term for particles found in the air, including soot, dust, smoke and liquid droplets. The smallest of these particles measure less than 2.5 micrometers, or roughly 1/30th the width of a human hair.
WHERE DOES IT COME FROM?
Major sources include coal-burning power plants, cars and trucks, factories and burning wood. PM 2.5 can be spewed directly into the air, or it can be created when gases from burning fuels react with sunlight and water vapor.
WHAT ARE THE HEALTH EFFECTS?
These tiny particles can lodge in deeper parts of the lungs that are more vulnerable to damage. Studies have shown a link between fine-particle exposure and increased cardiovascular disease, respiratory problems and premature death.
Source: U.S. EPA
Brian Urbaszewski with the American Lung Association of Metropolitan Chicago says studies like the one published today "only add weight to the need for tighter standards."
Researchers at Johns Hopkins Bloomberg School of Public Health and Yale University looked at hospitalizations from 1999 through 2002 for Medicare enrollees living in 204 urban counties, including Cook and the collar counties.
'This happens quite often'
"Our study is specific to the elderly, but there is epidemiological evidence that air pollution also affects the health of the younger population," said the study's lead author, Francesca Dominici.
The researchers found that short-term spikes in PM 2.5 levels, which are measured by outdoor monitors around the country, translated into more people being hospitalized for a variety of heart and lung ailments. For every 10 units that PM 2.5 levels jumped in the course of the day, there was one additional person hospitalized for heart failure.
"In Cook County, for example, about once every five days you'll have an increase in fine particulate matter of 10 units or more, so this happens quite often," Dominici said.
Proposed standards too weak?
Similar increases in hospitalization rates were seen among patients with chronic obstructive pulmonary disease and respiratory infections, such as pneumonia.
PM 2.5 is emitted from power-plant smokestacks and car and truck tailpipes, among other sources. It can be made up of many different substances, which might help explain why increases in PM 2.5 had different health effects depending on where participants lived.
"The Eastern region of the U.S., including Cook County and its neighboring counties, had a much stronger association between an increase in fine particulate matter and various cardiovascular outcomes, such as heart failure, ischemic heart disease and stroke," said co-author Roger Peng. "In the Western region we found a stronger association between increases in particulate matter and respiratory problems."
Peng questioned whether the EPA's proposed standards would be enough to reduce hospitalizations.
"In Cook County," he said, "the number of days with pollution above the proposed standards was only about 3 percent."