Their research results were published Oct. 8 in the Journal of the American Medical Association. The study was conducted at the Yale University School of Medicine. NIEHS is one of the federal National Institute of Health.

"Although the 1-hour average ozone levels in our study were well below the federal standard, statistical analysis revealed that for every 50 parts per billion increase in ozone, the likelihood of asthma symptoms the following day increased by more than 35 percent among asthmatic children on maintenance medication," said Brian Leaderer, Ph.D., the Susan Dwight Bliss Professor of Epidemiology at Yale University and principal investigator for the study.

Asthma, an inflammatory disorder of the airways that is characterized by periodic attacks of wheezing, shortness of breath and coughing, can be triggered by inhaled allergens such as pet dander, dust mites, molds or pollens. But researchers have also shown that air pollutants such as ground-level ozone, an active form of oxygen that is the prime ingredient of urban smog, and fine particulate matter, which includes dust, dirt, smoke and soot from a variety of natural and man-made sources, can significantly aggravate asthma symptoms.

Repeated exposures to ozone and fine particles at or above the federal standards can irritate or damage sensitive tissue in the airways and lungs, making breathing even more difficult for asthmatics and causing more attacks, increased use of medication, and more visits to hospital emergency clinics. Children are particularly vulnerable to these exposures because their respiratory systems are still developing, and they
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Contact: John Peterson
peterso4@niehs.nih.gov
919-541-7860
NIH/National Institute of Environmental Health Sciences
8-Oct-2003