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

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. 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 Oxwt) with ERVs for respiratory diseases. An interaction model was further performed to evaluate the interaction between O3 and NO2. Exposure to O3, NO2, Ox and Oxwt 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