Association and interaction of O3 and NO2 with emergency room visits for respiratory diseases in Beijing, China: a time-series study

Abstract

Abstract Background Ozone (O3) and nitrogen dioxide (NO2) are the two main gaseous pollutants in the atmosphere that act as oxidants. Their short-term effects and interaction on emergency room visits (ERVs) for respiratory diseases remain unclear. Methods We conducted a time-series study based on 144,326 ERVs for respiratory diseases of Peking University Third Hospital from 2014 to 2019 in Beijing, China. Generalized additive models with quasi-Poisson regression were performed to analyze the association of O3, NO2 and their composite indicators (Ox and Ox wt) with ERVs for respiratory diseases. An interaction model was further performed to evaluate the interaction between O3 and NO2. Results Exposure to O3, NO2, Ox and Ox wt was positively associated with ERVs for total respiratory diseases and acute upper respiratory infection (AURI). For instance, a 10 μg/m3 increase in O3 and NO2 were associated with 0.93% (95%CI: 0.05%, 1.81%) and 5.87% (95%CI: 3.92%, 7.85%) increase in AURI at lag0-5 days, respectively. Significant linear exposure–response relationships were observed in Ox and Ox wt over the entire concentration range. In stratification analysis, stronger associations were observed in the group aged 75% quantile) of NO2 in the < 18 years group. Conclusions Short-term exposure to O3 and NO2 was positively associated with ERVs for respiratory diseases, particularly in younger people (< 18 years). This study for the first time demonstrated the synergistic effect of O3 and NO2 on respiratory ERVs, and Ox and Ox wt may be potential proxies.

Keywords

• Air pollution
• Ozone
• Nitrogen dioxide
• Emergency room visits
• Respiratory diseases
• Interaction