The Effects of Daily Six Major Pollutants on the Risk of Respiratory Disease-Related Emergency Ambulance Calls: A Six-Year Time Series Study

BackgroundIn recent years, the impact of air pollution on the emergency departments of medical institutions has become increasingly evident. Emergency Ambulance Calls (EACs), compared to traditional health indicators such as mortality and hospitalization rates, provide a more direct reflection of the short-term effects of air pollution on public health. This study aims to explore the short-term association between the daily average concentrations of six major pollutants (PM2.5, PM10, SO2, NO2, CO, O3) and EACs related to respiratory diseases in the central urban areas of Shanghai. Methods: The Generalized Additive Model (GAM) was used to estimate the excess relative risk (ERR) of each pollutant on EACs at different lag times (0-7 days). Stratified analyses were also conducted based on age, time of day, and season. Results: 122,037 respiratory diseases related EACs were recorded during the study period. In different lag-day models, each interquartile range increase in pollutant concentration was associated with the highest single-day lag excess risk of EACs on the 6th day for all six pollutants, except for O3, which peaked on the 3rd day. The study found that individuals aged 65 and above are a vulnerable population to exposure. Specifically, in spring, PM2.5 on the 6th day of single-day lag was associated with a 3.19% (95% CI, 1.48-4.93%) increase in all-day EACs risk; PM10 on the 7th day of cumulative lag was associated with a 4.98% (95% CI, 1.35-8.74%) increase in daytime EACs risk; and O3 on the 3rd day of single-day lag was associated with a 3.60% increase in daytime EACs risk among the elderly (95% CI, 1.19-6.06%). Conclusion: This study indicates that even under the national ambient air pollutant concentration limits, air pollution could still serve as significant triggers for acute respiratory disease exacerbations. It is recommended that stricter air pollution control and early warning policies be implemented to reduce the occurrence of respiratory disease-related emergencies.