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Rob McConnell,¹ Kiros Berhane,¹ Frank Gilliland,¹ Stephanie J. London,² Hita Vora,¹ Edward Avol,¹ W. James Gauderman,¹ Helene G. Margolis,³ Fred Lurmann,⁴ Duncan C. Thomas,¹ and John M. Peters¹

¹Department of Preventive Medicine, University of Southern California School of Medicine, Los Angeles, California, USA
²National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
³California Air Resources Board, Sacramento, California, USA
⁴Sonoma Technology Inc., Petaluma, California, USA

Abstract

The association of air pollution with the prevalence of chronic lower respiratory tract symptoms among children with a history of asthma or related symptoms was examined in a cross-sectional study. Parents of a total of 3,676 fourth, seventh, and tenth graders from classrooms in 12 communities in Southern California completed questionnaires that characterized the children's histories of respiratory illness and associated risk factors. The prevalences of bronchitis, chronic phlegm, and chronic cough were investigated among children with a history of asthma, wheeze without diagnosed asthma, and neither wheeze nor asthma. Average ambient annual exposure to ozone, particulate matter (PM₁₀ and PM_2.5 ; 10 µm and < 2.5 µm in aerodynamic diameter, respectively) , acid vapor, and nitrogen dioxide (NO₂) was estimated from monitoring stations in each community. Positive associations between air pollution and bronchitis and phlegm were observed only among children with asthma. As PM₁₀ increased across communities, there was a corresponding increase in the risk per interquartile range of bronchitis [odds ratio (OR) 1.4/19 µg/m³ ; 95% confidence interval (CI) , 1.1-1.8) . Increased prevalence of phlegm was significantly associated with increasing exposure to all ambient pollutants except ozone. The strongest association was for NO₂, based on relative risk per interquartile range in the 12 communities (OR 2.7/24 ppb ; CI, 1.4-5.3) . The results suggest that children with a prior diagnosis of asthma are more likely to develop persistent lower respiratory tract symptoms when exposed to air pollution in Southern California. Key words: air pollution, asthma, bronchitis, children, respiratory tract. Environ Health Perspect 107:757-760 (1999) . [Online 5 August 1999]

http://ehpnet1.niehs.nih.gov/docs/1999/107p757-760mcconnell/ abstract.html

Address correspondence to R. McConnell, Department of Preventive Medicine, USC School of Medicine, 1540 Alcazar Street, CHP 236, Los Angeles, CA 90033 USA. Telephone: (323) 442-1593. Fax: (323) 442-3272. E-mail: rmcconne@hsc.usc.edu

We are grateful for the important input from our External Advisory Committee: D. Bates, M. Lippmann, J. Samet, J. Spengler, F. Speizer, J. Whittenberger, A. Winer, and S. Zeger. In addition, W. Linn, H. Gong, G. Cass, S. Colome, S. Hering, W. McDonnell, R. Reiss, and P. Roberts provided excellent advice. We acknowledge the hard work of the study field team and the cooperation of the 12 communities, the school principals, the many teachers, the students, and their parents. Programming support was provided by E. Rappaport and J. Manila. S.S. Stanley provided clerical support.

This study was supported by the California Air Resources Board (contract A033-186) , the National Institute of Environmental Health Science (grant #5P30ES07048-02) , the U.S. Environmental Protection Agency (contract #CR824034-01-3) , and the Hastings Foundation.

The statements and conclusions in this report are those of the contractor and not necessarily those of the California Air Resources Board. The mention of commercial products, their source, or their use in connection with material reported herein is not to be construed as either an actual or implied endorsement of such products.

Received 1 February 1999 ; accepted 1 June 1999.