Air pollutants and asthma patient visits: Indication of source influence

Abstract

BackgroundSources of air pollutants are significant factors for adverse health effect. Few current studies explored the linking of sources influence and ambient pollutants to asthma patient visits in Shanghai, China. ObjectivesThis study explored the associations between short-term exposures to ambient pollutants and asthma morbidity with terrestrial and marine source influence in Shanghai. MethodsGeneralized additive model (GAM) was used to explore the association of daily patient visits and ambient pollutants. These analyses were calculated in R statistical software in mgcv package. PSCF modeling was used to locate potential source areas contributing to the concentrations of pollutants. ResultsWe found that per IQR of PM2.5, PM10, NO2, SO2, O3 and CO in terrestrial source were associated with an increase of 6.63% (95% CI: −0.27% to 14%), 6.48% (95% CI: 0.06% to 13.3%), 1.68% (95% CI: −2.68% to 6.24%), 2.81% (95% CI: −1.42% to 7.22%), −0.60% (95% CI: −5.94% to 5.04%) and 16.6% (95% CI: 8.68% to 25.2%), respectively in asthma patient visits. Per IQR of PM2.5, PM10, NO2, SO2, O3 and CO in marine source were associated with an increase of 5.34% (95% CI: 0.42% to 10.5%), 3.84% (95% CI: 0.08% to 7.74%), 3.21% (95% CI: −0.92% to 7.52%), 2.58% (95% CI: −1.02% to 6.30%), 1.42% (95% CI: −3.10% to 6.15%) and 8.81% (95% CI: 2.56% to 15.4%). The PSCF show all of the pollutants except O3 mainly come from terrestrial during observation. We also found that all of the pollutants except NO2 displayed the highest effect in the spring for relative risk of asthma morbidity. ConclusionsAmbient air pollutants that cause an increase in asthma patient visits, such as PM2.5, PM10, NO2, SO2 and CO are mainly produced from terrestrial sources, while O3 is primarily from marine sources. The association of ambient pollutants and asthma patient visits is closely related with seasons, especially with spring. PM2.5 and CO are major air pollutants increasing the relative risk of asthma patient visits in Shanghai.