Objective To evaluate the short-term health effects of air pollutants on outpatient visits for respiratory diseases in Shanghai.
Methods Daily data on outpatient visits to a Grade III Class A hospital for respiratory diseases, meteorological data, and air pollution data from January 1, 2010 to October 31, 2012 were collected. A time-series analysis by generalized additive model was conducted to examine the relationship between air pollutants and daily outpatient visits, controlling for time trends, day-of-week effect, holiday effect, and weather conditions.
Results The daily outpatient visits for respiratory diseases ranged from 76 to 382 over the study period. In the single-pollutant model, SO2 concentration with lagged 4 days and NO2 and PM10 concentrations with lagged 6 days showed the most significant influence on outpatient visits. The excess relative risks of daily outpatient visits for a 10-μg/m3 increment in SO2, NO2, and PM10 were 0.69% (RR=1.006 9, 95% CI: 1.003 5-1.010 3), 0.54% (RR=1.005 4, 95% CI: 1.002 8-1.007 9), and 0.20% (RR=1.002 0, 95% CI: 1.001 1-1.002 8), respectively. In the multiple-pollutant models, all pollutants effect estimates were lower compared with the results of the single-pollutant model when other pollutants were adjusted, but the positive correlations still existed between the pollutants and the daily outpatient visits for respiratory diseases.
Conclusion The ambient air pollutant concentrations of SO2, NO2, and PM10 are positively associated with daily outpatient visits for respiratory diseases.
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