Study sees threat from big-particle pollutants

By Andrew Stern

CHICAGO (Reuters) - On days when there is a lot of dust and other large-particle pollutants in the air, slightly more elderly people go to hospital emergency rooms with heart problems, U.S. researchers said on Tuesday.

There was also an increase in hospital visits by elderly patients complaining of respiratory illnesses when "coarse," or large, particle pollution was plentiful, although the rise was not significant, the researchers said.

"Though the evidence is mixed at this point, we did find an association between cardiovascular admissions and coarse particulate matter," Roger Peng of Johns Hopkins University in Baltimore, who led the study, said in a telephone interview.

"So I think it's important that we update this study and others like it using continuing monitoring data" collected by government pollution sensors across the United States.

Peng and others have previously identified the dangers to hearts and lungs posed by fine airborne particles, which are smaller than 2.5 microns across, or 100 times tinier than the width of a human hair.

Smaller particles spewed in vehicle exhaust and from other sources can travel farther than coarse particles and, when inhaled, can penetrate deeper into the lungs. If they become trapped, it raises the risks of illnesses that include emphysema, lung cancer and heart disease.

"It is fairly well known that fine particulate matter ... has adverse health effects," said Francesca Dominici, another Johns Hopkins researcher who worked on the study.

DUSTIER IN THE WEST