摘要：This study examines the relationship of asthma emergency department (ED) visits to daily concentrations of ozone and other air pollutants in Saint John, New Brunswick, Canada. Data on ED visits with a presenting complaint of asthma (n = 1987) were abstracted for the period 1984-1992 (May-September). Air pollution variables included ozone, sulfur dioxide, nitrogen dioxide, sulfate, and total suspended particulate (TSP); weather variables included temperature, humidex, dewpoint, and relative humidity. Daily ED visit frequencies were filtered to remove day of the week and long wave trends, and filtered values were regressed on air pollution and weather variables for the same day and the 3 previous days. The mean daily 1-hr maximum ozone concentration during the study period was 41.6 ppb. A positive, statistically significant (p < 0.05) association was observed between ozone and asthma ED visits 2 days later, and the strength of the association was greater in nonlinear models. The frequency of asthma ED visits was 33% higher (95% CI, 10-56%) when the daily 1-hr maximum ozone concentration exceeded 75 ppb (the 95th percentile). The ozone effect was not significantly influenced by the addition of weather or other pollutant variables into the model or by the exclusion of repeat ED visits. However, given the limited number of sampling days for sulfate and TSP, a particulate effect could not be ruled out. We detected a significant association between ozone and asthma ED visits, despite the vast majority of sampling days being below current U.S. and Canadian standards. Full text Full text is available as a scanned copy of the original print version. Get a printable copy (PDF file) of the complete article (2.2M), or click on a page image below to browse page by page. Links to PubMed are also available for Selected References . 1354 1355 1356 1357 1358 1359 1360
Loading...
