Guojun He, Yuhang Pan, and Takanao Tanaka
Replication Codes for Paper "The Short-term Impacts of COVID-19 Lockdown on Urban Air Pollution in China "
This repository contains data and codes that can be used to reproduce the results found in the manuscript "The Short-term Impacts of COVID-19 Lockdown on Urban Air Pollution in China ".
Abstract: To prevent the escalation of COVID-19 transmission, China locked down one-third of its cities, which strictly restricted personal mobility and economic activities. Using daily comprehensive air quality data in China, we evaluate the impacts of these measures on the Air Quality Index (AQI) and PM2.5 concentrations. To infer their causal relationships, we employ difference-in-differences models that compare cities with and without lockdown policies. We find that city lockdowns led to a significant improvement in air quality. Within weeks, the AQI in the locked-down cities was brought down by 19.84 points (PM2.5 down by 14.07 µg/m3) relative to the control group. In addition, in cities without formal lockdowns, air quality also improved because of the enforcement of other types of counter-virus measures. AQI in those cities was brought down by 6.34 points (PM2.5 down by 7.05 µg/m3) relative to the previous year. The lockdown effects are larger in colder, richer, and more industrialized cities. Despite these improvements, PM2.5 concentration during the lockdown periods remained four times above the WHO recommendations, suggesting much further efforts are needed. Besides, previous environmental policies could obtain similar air quality improvement at a much lower economic cost, making city lockdowns an unsustainable option to address environmental issues.
Link to the Paper at Nature Sustainability: https://www.nature.com/articles/s41893-020-0581-y
For replication issues, please feel free to contact us at yhyhpan [at] gmail.com.