Asthmatic Children Vulnerable to Even Low Levels of Ozone

Children with severe asthma are particularly vulnerable to ozone in air pollution even at levels below Environmental Protection Agency (EPA) standards, Yale researchers report in the October 8 issue of Journal of the American Medical Association.

During the spring and summer of 2001, daily measurements of respiratory symptoms (wheezing, coughing, shortness of breath, chest tightness) and asthma medication use for 271 children with active asthma were coupled with air pollution data from the Departments of Environmental Protection of Connecticut and Massachusetts.

In the period covered by the study, fine particles in air pollution never exceeded EPA standards and one-hour peak ozone levels exceeded EPA standards on only three days.

Statistical analysis revealed that for every 50 parts per billion (ppb) increase in ozone level, the likelihood of wheezing increased by 35 percent and chest tightness by 47 percent among asthmatic children on maintenance medication. Increase in shortness of breath (by 32 percent) and rescue medication use (by eight percent) coincided with the highest levels of ozone.

Earlier studies of children with asthma living in highly polluted regions, such as Mexico City and Los Angeles, conclude that ozone and fine particles regularly in excess of EPA standards (65 micrograms per cubic meter for fine particles and 120 ppb for ozone) greatly increase the risk for respiratory symptoms, asthma medication use, and reduced lung function.

“These results extend previous work suggesting that ozone, even at levels below current EPA standards, is strongly associated with adverse health effects in children with asthma,” said first author Janneane Gent, associate research scientist in the Department of Epidemiology and Public Health at Yale School of Medicine.

Gent’s Yale colleagues on the study include principal investigator Brian Leaderer, Elizabeth Triche, Theodore Holford, Kathleen Belanger and Michael Bracken. William Beckett, M.D. of the University of Rochester also participated on the study.

The National Institute of Environmental Health Sciences funded the study. >P> Citation: Journal of The American Medical Association, Vol. 290, No. 14, October 8, 2003.

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Karen N. Peart: karen.peart@yale.edu, 203-432-1326