Objective To calculate the relative risk of health center visiting due to upper respiratory diseases associated with air pollutants and evaluate the health effects of various pollutants.
Methods Data of outpatients and air monitoring were collected in 2011-2013. Distributed lag non-linear models (DLNM) were used to calculate the relative risk of health center visiting volume due to upper respiratory diseases associated with various air pollutants, and compare the lag-specific and doseresponse relationships.
Results Positive correlations were seen between selected air pollutants and outpatient number, and the outpatient number increased with higher concentrations. Steeper increases of the relative risk were found for sulfur dioxide (SO2) and fine particulate matters (PM2.5) at low concentrations, and plateaus or reductions were found at high concentrations. The relative risk for nitrogen dioxide (NO2) was lower at low concentrations, but the plateau period was insignificant on the day polluted. The longest lag days of SO2 and NO2 were short. The overall cumulative effect of PM2.5 was greater than the other pollutants, which caused longer lag days.
Conclusion All three pollutants associate positively with health center visiting due to upper respiratory disease. Effects of SO2 and NO2 may be mainly acute, while lag-specific effect of PM2.5 may be more obvious. Adverse health effects could be seen at low SO2 concentration or at high NO2 concentration.
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