Exposure to Ambient Air Pollutions and Upper Respiratory Tract Infection in Zhengzhou City, China: A Approximate Five-Year Surveillance Study

Background: Studies indicated that air pollutions were associated with respiratory disease have with a lag exposure–response relationship, but not linear. However, few evidences in Zhengzhou, one of the most polluted cities for China.Method: Upper respiratory tract infection (URTI) outpatient visits in the hospital, meteorological parameters and air pollutions data were obtained from October 28, 2013 to May 1, 2018 and were used for evaluating the risk effects of the air pollutants with a distributed lag non-linear model (DLNM), including the stratified analysis of gender and age.Result: 475013 cases were included, with obvious seasonal fluctuations,higher in cool/cold and lower in warm. Every increase of 10μg/m3 of PM2.5, PM10, SO2, NO2 and CO showed similar impacts on URTI outpatient visits in different genders and age sub-groups,within 0 to15 days of lag. PM10, SO2 and NO2 had the strongest immediately risk at lag 0 [RRPM10: 1.0011, 95%CI (1.0002-1.0020); RRSO2: 1.0084, 95%CI (1.0039-1.0130); RRNO2: 1.0149, 95%CI: (1.0111-1.0188), respectively], while PM2.5 and CO got highest risk at lag 15 days [RRPM2.5: 1.0014, 95%CI (1.0003-1.0025); RRCO: 1.0002, 95%CI: (1.0001-1.0003), respectively]. In addition, calculating overall accumulated effects of each 10μg/m3 increase in PM10, SO2, NO2, and CO was greater in females than in males, as well as greater in the adolescents (aged 0-18 years) and elderly (aged ≥ 60 years) than in adults (aged 19-59 years), except CO was greater in the adolescents and adults than in the elderly. No significant cumulative effects were found in PM2.5. O3 levelwasno significant correlation withURTI outpatient visits throughout the lag period.Conclusions: Our results indicated that PM10, SO2, NO2 and CO had strong immediate and lag cumulative effects in the females, adolescents, and elderly. PM2.5 has lag effects but has no significant lag cumulative impact effects on gender and age.