"We are just beginning to realize that these microscopic specks of dust and soot are far more toxic in the human body than larger, coarser particles," said Constantinos Sioutas, deputy director and co-principal investigator of USC's Southern California Particle Center and Supersite.

"They aren't trapped by the nose and trachea, but travel all the way down to the tiniest branches of the lungs and enter the bloodstream through the alveoli, which are very thin-walled sacs of spongy tissue at the ends of the bronchioles," said Sioutas, an associate professor of civil and environmental engineering in the USC School of Engineering.

More residents than ever are falling prey to microscopic soot less than 1/100th the diameter of a human hair. These particles, known as "particulate matter" or PM, lodge deep inside the lungs, where they are rapidly absorbed into the bloodstream or remain embedded for long periods of time.

Particle smog has been blamed for a 17-percent increase in premature deaths from heart and lung disease, according to recent studies by Harvard University and the National Institutes of Health, among others.

Nationwide, this invisible soot - which is less than 2.5 microns in diameter - has been linked to roughly 60,000 smog-related deaths in the United States each year.

In 2000, the Environmental Protection Agency responded to the paucity of information about particulate matter by establishing the Southern California Particle Center and Supersite, the nation's largest research center focused on understanding the health effects of exposure to airborne particulate matter.

With an $18 million grant, the center brought together interdisciplinary faculty from five instit
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Contact: Diane Ainsworth
dainswor@usc.edu
213-821-5808
University of Southern California
17-Dec-2003