National study examines health risks of coarse particle pollution

May 13, 2008

Researchers at the Johns Hopkins Bloomberg School of Public Health have conducted the largest nationwide study on the acute health effects of coarse particle pollution. Coarse particles are airborne pollutants that fall between 2.5 and 10 microns in diameter. These particles are larger than fine particles (less than 2.5 microns) and are produced by processes such as mechanical grinding, windblown dust and agriculture. These particles are of interest from both public health and regulatory perspectives.

The researchers examined associations between daily changes in hospital admissions rates for cardiovascular and respiratory outcomes and daily changes in coarse and fine particulate matter levels for 108 urban U.S. counties, which included approximately 12 million people enrolled in Medicare during the years 1999 through 2005.

The study, published in the May 14, 2008, edition of JAMA, found no evidence of an association between daily changes in coarse particles and the number of hospital admissions for respiratory diseases. The study found evidence of an association with hospital admissions for cardiovascular diseases. After taking into account fine particle levels, the association with coarse particles remained but was no longer statistically significant. The study also found that the risk of a cardiovascular hospital admission due to coarse particles was higher in more urban counties.

“Overall, the evidence was mixed, but the data suggest a link between cardiovascular admissions and ambient exposure to coarse particulate matter. This association was not statistically significant when we adjusted for fine particulate matter,” said Roger D. Peng, PhD, lead author of the study and an assistant professor in the Bloomberg School’s Department of Biostatistics.

“Although the evidence was not conclusive, the benefit of our approach is that it can be easily replicated when new data become available. Given that we found an association with coarse particles before taking into account fine particulate matter, our findings need consideration when the Environmental Protection Agency’s standard for particles in the air is next reviewed.”

The EPA regulates the levels of fine particle pollution, but does not yet have a standard for coarse particle pollution.

Previous studies by the Hopkins researchers demonstrated a strong link between fine particulate matter pollution and increased hospital admissions for cardiovascular and respiratory illnesses.

“We found continued evidence of an association between fine particulate matter and risk for hospitalization in this new data set, an extension by three years of our previous analyses,” said senior author Francesca Dominici, PhD, professor in Biostatistics. “We urge continued monitoring of the coarse fraction of particulate matter so that further studies can be carried out.”

Source: Johns Hopkins University

Explore further: Biomedical imaging at one-thousandth the cost

Related Stories

Biomedical imaging at one-thousandth the cost

November 23, 2015

MIT researchers have developed a biomedical imaging system that could ultimately replace a $100,000 piece of a lab equipment with components that cost just hundreds of dollars.

Indoor air pollution increases asthma symptoms

February 19, 2009

A study by researchers at the Johns Hopkins University found an association between increasing levels of indoor particulate matter pollution and the severity of asthma symptoms among children. The study, which followed a ...

'Refinery dust' reveals clues about local polluters

January 12, 2009

Cloaked in the clouds of emissions and exhaust that hang over the city are clues that lead back to the polluting culprits, and a research team led by the University of Houston is hot on their trails.

Agricultural bacteria: Blowing in the wind

May 9, 2012

The 1930s Dust Bowl proved what a disastrous effect wind can have on dry, unprotected topsoil. Now a new study has uncovered a less obvious, but equally troubling impact of wind: Not only can it carry away soil particles, ...

Recommended for you

How the finch changes its tune

August 3, 2015

Like top musicians, songbirds train from a young age to weed out errors and trim variability from their songs, ultimately becoming consistent and reliable performers. But as with human musicians, even the best are not machines. ...

Machine Translates Thoughts into Speech in Real Time

December 21, 2009

( -- By implanting an electrode into the brain of a person with locked-in syndrome, scientists have demonstrated how to wirelessly transmit neural signals to a speech synthesizer. The "thought-to-speech" process ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.