COVID-19 Cannot Sustainably Improve Air Quality: Evidence from Reopening an Economy

One “silver lining” of the COVID-19 pandemic has been the reduction in air pollution that followed lockdowns. Unfortunately, this unintended air pollution decline will likely be short-lived. As regions begin to recover their economies, travel and industrial activity will increase the ambient pollutants quickly offsetting the improvement in air quality. Therefore, it is urgent to clarify the causal impact of reopening an economy on air quality during COVID-19. Based on city-level daily air quality data in China, this paper is the first to empirically analyze the causal effect of reopening the economy in the provincial capital Lanzhou on concentrations of four air pollutants using the synthetic control method. The results show that the reopening caused a significant increase in the concentration of NO2 by as much as 30 μg/m3 (an increase of 75% from the lockdown level) and a significant increase in O3 concentrations by 60μg/m3 (a 60% increase) which peaked on the 6th day after the restart. The reopening also led to significant fluctuations in SO2 and CO concentrations. This study contains useful conclusions by providing timely and reliable causal evidence on the lasting impact of COVID-19 on air quality.