Air Pollution and Childhood Asthma Hospitalizations in Chengdu, China: A Time-Series Study.

Research on the relationship between air pollutants and hospitalization for asthma in children in developing countries remains inadequate. This study aimed to assess the short-term effects of air pollutants, including sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), ozone (O3), particulate matter ≤ 2.5 µm (PM2.5), and particulate matter ≤ 10 µm (PM10), on children hospitalized for asthma in Chengdu, China, from 2017-2022. During the study period, 5592 children were hospitalized for asthma. A generalized additive model was used to control for seasonality, long-term trends, weather, day of the week, and holidays. The analysis was further stratified by age, sex, and season to estimate the associations. PM2.5, PM10, SO2, NO2, and CO were significantly associated with an increased risk of hospitalization due to asthma. A 10 μg/m3 increase in PM2.5, PM10, and CO at lag04 corresponded to an increase of 2.07%, 1.56%, and 0.33% in daily hospital admissions for asthma, respectively. A 10 μg/m3 increase in SO2 and NO2 at lag05 corresponded to an increase of 45.69% and 8.16% in daily hospital admissions for asthma, respectively. Further analysis by age found that PM10 and PM2.5 had a greater impact on children aged 5-6 years old while NO2 and CO mainly affected children under 7 years old. Analysis by by sex found that pollutants had a greater impact on hospital admissions in girls. Seasonal analysis revealed that pollutants had a more significant effect on admission during the winter. Our results suggest that increased concentrations of PM2.5, PM10, SO2, NO2, and CO in Chengdu lead to hospitalization for asthma in children and that a lag effect was observed, especially with SO2. These findings highlight the need for stricter air quality controls to reduce childhood asthma hospitalizations.