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

Abstract

Purpose: 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. Patients and Methods: 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. Results: 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. Conclusion: 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.