The Effect of Coronavirus 2019 Disease Control Measures on the Incidence of Respiratory Infectious Disease and Air Pollutant Concentrations in Yangtze River Delta Region, China

To investigate the changes of the respiratory infectious diseases (RID) and air quality during the COVID-19 outbreak over Yangtze River Delta Region, China. We investigate the impact of COVID-19 control measures on changes of RID and air quality by constructing two proportional test and fitting ARIMA and piecewise regression models. A total of 81,345 and 1,048,511 cases of RID were identified in Shanghai and Zhejiang Province, respectively. The incidence of seven RID and influenza decreased by 37.80% and 49.57% in 2020 in Shanghai and decreased by 20.39% and 43.40% in Zhejiang Province, respectively. The monthly concentrations of overall air pollutants decreased by 12.7% and 12.85% in 2020 Shanghai and Zhejiang compared to the 2017–2019 period; the most rapid decrease was observed in SO2 concentrations (32.39% and 33.37% in Shanghai Province and Zhejiang Province, respectively). A moderate correlation was seen between influenza incidence and monthly SO2 concentrations in Shanghai (r = 0.59). A 10 μg/m3 decrease of SO2 was significantly associated with the reduction of influenza incidence(2907.76 per 100,000). This study provided the additional evidences that the measures taken for COVID-19 were effective in improving the air quality and reducing spread of other common respiratory diseases, but direct causality is not established.