Low-Level Ozone and Particulate Matter Pollution is Associated with Respiratory Symptoms in Children with Asthma

Brian P. Leaderer, Ph.D., Yale University School of Medicine
William S. Beckett, Ph.D., University of Rochester School of Medicine and Dentistry
R01ES07456, R01ES05410, R01ES11013, and P30ES01247

Background: Many studies have shown that children with asthma are particularly vulnerable to adverse health effects from exposure to high levels of the air pollutants ozone and particulate matter. These studies have shown that children with asthma living in areas that regularly experience periods of high levels of these ambient pollutants are at significant risk for respiratory symptoms, the need for asthma medication use, and decreases in lung function. Other epidemiologic studies of children with asthma living in regions with levels of pollution within or near compliance with EPA standards suggest that these standards may not be protective of this more vulnerable group. The current study conducted by NIEHS grantees at the Yale University School of Medicine examines simultaneous effects of ozone and particulate matter at levels below EPA standards on daily respiratory symptoms and rescue medication use.

Advance: Ozone levels, but not particulate matter was significantly associated with respiratory symptoms and rescue medication use among children using maintenance medication. The 1-hour average (59 parts per billion) and 8-hour average (51 parts per billion) levels of ozone were significantly lower than the EPA standards of 120 and 80 respectively. No exposure-dependent associations were observed for any outcome by either pollutant among children not using maintenance medication.

Implication: The finding that asthmatic children are particularly vulnerable to ozone at levels below current EPA standards has major public health implications. On days when the ozone levels are considered safe for the general population, this at-risk group may need to take additional precautions. Parents and physicians need to be aware of ozone alert forecasts and may need to take measures to limit outdoor activity and exercise for children with asthma on days when ozone is elevated but not exceeding accepted standards.

Citation: Gent, JF, Triche EW, Holford TR, Belanger K, Bracken MB, Beckett, WS and Leaderer, BP. Association of Low-Level Ozone and Fine Particles with Respiratory Symptoms in Children with Asthma. JAMA, 2003; 290:1859-1867.