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Patrick L. Kinney,¹ George D. Thurston,² and Mark Raizenne³

¹Division of Environmental Sciences, Columbia University School of Public Health, New York, NY 10032 USA; ²Institute of Environmental Medicine, New York University Medical Center, Long Meadow Road, Tuxedo, NY 10987 USA; ³Health Canada, Ottawa, Ontario, Canada

Abstract
Studies of children attending summer camps often have observed relationships between daily outdoor ozone (O₃) concentrations and decreased lung function that are qualitatively similar to results seen in human chamber studies. The former studies, focusing on the pulmonary effects of O₃ and associated pollutants on children under natural conditions of exposure, are potentially of great importance to understanding the public health impact of ambient O₃. However, a thorough assessment of the results of these studies has been hampered by differences in the analysis and reporting of data across the various studies. We obtained data sets from six summer camp studies carried out by three separate investigative groups, including two New Jersey studies performed by New York University, two studies in Ontario carried out by Health and Welfare Canada, and two studies in southern California. The data consisted of sequential, daily measurements of forced expiratory volume in 1 sec (FEV₁) , peak expiratory flow rate (PEFR) , and 1-hr O₃ concentration in the hour preceding lung function measurements for each child. We analyzed the relationships between lung function and O₃ using linear regression models that fit subject-specific intercepts and a single, pooled O₃ slope. These models were fit for each of the six studies separately and for all studies combined. All of the study-specific slopes of FEV₁ on O₃ were negative (i.e., increased O₃ associated with decreased FEV₁) ; five of six were statistically significant. Analysis of the combined six-study data set yielded a slope of -0.50 ml FEV₁/ppb O₃ (p<0.0001) . Addition of time-trend variables to the combined-data analysis diminished, but did not eliminate, the FEV₁-O₃ relationship. Study-specific slopes for PEFR on O₃ were more variable. Combined over studies, no significant relationship was observed between PEFR and O₃. However, this negative finding appeared to be partially confounded by time trends in PEFR. The results of this reanalysis provide strong evidence that children exposed to O₃ under natural conditions experience decreases in FEV₁ of the kind demonstrated in laboratory studies, and raise concern that other acute respiratory effects observed in those studies (e.g., pulmonary inflammation) may also occur in young people exposed to ambient O₃. Key words: air pollution, children, epidemiology, lung/pulmonary function, ozone, summer camps. Environ Health Perspect 104:170-174 (1996)

Address correspondence to P. L. Kinney, Division of Environmental Sciences, Columbia University School of Public Health, 60 Haven Avenue, B-1, New York, NY 10032 USA.

We thank Mort Lippmann and Dalia Spektor of New York University for providing the Fairview Lake study data sets ; Haluk Ozkaynak of Harvard University for the Pine Springs study data set ; and Diane Gibbons of General Motors Corporation, who provided Haluk Ozkaynak with the Pine Springs data. The two Canadian camp studies and the San Bernardino study data sets were provided by Mark Raizenne. Funding was provided by contracts from Health and Welfare Canada.

Received 14 April 1995 ; accepted 20 November 1995.