AIR POLLUTION AND ASTHMA EMERGENCY ROOM VISITS IN RENO, NEVADA

Abstract

The association between air pollution and the daily number of emergency room (ER) visits for asthma was assessed in Reno, Nevada, for the period 1992-1994. All three hospitals in the region were included. There was a total of 1593 ER visits for asthma during this period of time. The air pollution variables were collected from seven monitoring stations, including particulate matter (PM-10), ozone (O3), and carbon monoxide (CO). Levels of pollution were moderately elevated (the average concentrations of PM-10, CO, and O3 3 were 38.0 g/m, 4.55 ppm, and 51.0 ppb, respectively). Weighted least-squares (WLS) regression and autoregressive integrated moving average (ARIMA) time-series analyses were applied and compared. After adjusting for such factors as day of the week, seasonal variation, and weather, both modeling methods showed that the daily 1-h maximum O3 concentration was a significant predictor of asthma ER visits, although ARIMA increased the magnitude of the estimated response after controlling the autocorrelated errors. Total asthma visits were found to increase 33.7% (95% CI; range 6.0-61.5%) for each 100 ppb increase in the O3 level. No association of the concentration of other measured pollutants with daily asthma ER visits was found. The results provide evidence that O3 pollution concentrations even below the federal standard may have an adverse effect on the respiratory health of susceptible persons. Further research will be conducted, examining the effects of ambient air pollution concentrations on other respiratory diseases in Reno.