Association between air pollution and emergency department visits for upper respiratory tract infection inLanzhou, China.

There is limited evidence regarding the associations between air pollution and emergency hospital visits for upper respiratory tract infection (URTI) in the arid regions of northwest China. We collected daily emergency department (ED) visits for URTI from three hospitals in Lanzhou during January 2014 and December 2018, as well as daily air pollutants and meteorological factors. In the present study, generalized additive model with quasi-Poisson regression was used to evaluate the relationship between short-term exposure to ambient pollutants and daily emergency hospital visits for URTI in Lanzhou, China. Furthermore, subgroup analyses were conducted by gender (male and female), age (0-14, 15-64, and ≥ 65 years)), and season (cold season, warm season). The results of the single-pollutant model show that the associations of PM, PM, SO, NO, and CO with URTI ED visits were all statistically significant, whereas we observed insignificant associations of O8h. The highest association of each pollutant with hospital emergency visits was observed with PM (5.302% (95% CI: 3.202, 7.445)), PM (0.808% (95% CI: 0.291, 1.328)), SO (10.607% (95% CI: 5.819, 15.611)), and NO (5.325% (95% CI: 2.379, 8.357)) at lag 07 for an increase of 10 ug/m in concentrations of the pollutants. Percentage increase for each 1-mg/m increase in CO was 20.799% (95% CI: 11.834, 30.482) at lag 07. In the stratification analyses, females were more susceptible to PM and PM, while males were more sensitive to the effects of SO, NO, and CO, and the higher association effect of four pollutants (PM, SO, NO, and CO) on hospital visits for URTI among children (0-14 years). The associations appeared to be stronger in the cool season than in the warm season. This study suggests that short-term exposure to air pollution, especially to SO and CO, was associated with increased risk of hospital emergency visits for URTI in Lanzhou, China. Relevant strategies and health interventions should be strengthened to reduce the air pollution level in the future.