Effects of COVID-19 lockdown on global air quality and health

Abstract

The COVID-19 pandemic has put much of the world into lockdown, as one unintended upside to this response, the air quality has been widely reported to have improved worldwide. Existing studies examine the environmental effect of lockdowns at a city- or country-level, few examines it from a global perspective. Using a novel COVID-19 government response tracker dataset, combining the daily air pollution data and weather data across 597 major cities worldwide between January 1, 2020, and July 5, 2020, this study quantifies the causal impacts of 8 types of lockdown measures on changes of a range of individual pollutants based on a difference-in-differences design. The results show that the NO 2 air quality index value falls more precipitously (23–37%) relative to the pre-lockdown period, followed by PM 10 (14–20%), SO 2 (2–20%), PM 2.5 (7–16%), and CO (7–11%), but the O 3 increases 10–27%. Furthermore, intra/intercity travel restrictions have a better performance in curbing air pollution. These results are robust to a set of alternative specifications, including different panel sizes, independent variables, estimation strategies. The heterogeneity analysis in terms of different types of cities shows that the lockdown effects are more remarkable in cities from lower-income, more industrialized, and populous countries. We also do a back-of-the-envelope calculation of the subsequent health benefits following such improvement, and the expected averted premature deaths due to air pollution declines are around 99,270 to 146,649 among 76 countries and regions involved in this study during the COVID-19 lockdown. These findings underscore the importance of continuous air pollution control strategies to protect human health and reduce the associated social welfare loss both during and after the COVID-19 pandemic.

Multiple relationships between aerosol and COVID-19: A framework for global studies

“…The prevention and control measures taken by these countries have greatly reduced the transmission rates of COVID-19 ( Koyama et al, 2020 ). With the large-scale shutdowns and traffic restrictions, the aerosol pollution had a general corresponding decrease in levels ( Zhou et al, 2012 ; Liu et al, 2021 ; Shi et al, 2021 ). The results of aerosol concentration changes in different regions during the COVID-19 lockdown are summarized in Fig.…”

“…The large reduction of human activities has significantly improved air quality in many areas during the control of COVID-19. Compared with the pre-lockdown period, the concentrations of PM 10 (14–20%) and PM 2.5 (7–16%) in 597 major cities in the world have decreased significantly ( Liu et al, 2021 ). For the areas with more serious air pollution problems, the improvement of the aerosol is greater, and the decrease of PM 2.5 is greater than that of PM 10 ( Fig.…”

“…Some studies have investigated the reasons for the decrease of atmospheric aerosol concentrations. Measures such as city closure and vehicle restrictions greatly reduced the types of primary aerosols related to traffic and reduced the levels of air pollution ( Liu et al, 2021 ; Chen et al, 2021 ), and at the same time, many factories shut down and stop production, and the emission of the secondary industry decreased ( Wang et al, 2020c ). In Beijing, the vast majority of restaurants were closed, and the aerosol emissions of cooking and gas burning decreased by 30–50% on average ( Sun et al, 2020 ).…”

Exposure to Atmospheric Particulate Matter-Bound Polycyclic Aromatic Hydrocarbons and Their Health Effects: A Review

“…were largely limited in many countries. Although the harm caused by COVID-19 is very large, several studies found that these control measures could greatly affect air pollutants emissions and the air quality, and the premature deaths due to improved air quality declined in many countries and regions [ 174 , 175 , 176 , 177 ], suggesting the control of air pollution should be more strengthened.…”

National Lockdown to Cope with COVID-19 Pandemic: Effects (Contradictory) on Public Health and (Negative) on Economic System

“…In this context, Liu et al (2021) analyze the effects of COVID-19 lockdown in about 600 major cities worldwide and show that NO 2 air quality index value falls more precipitously relative to the pre-lockdown period, followed by PM 10 , SO 2 , PM 2.5 , and CO, but the level of O 3 increases. Moreover, Liu et al (2021) argue that the impact of COVID-19 lockdown on environmental pollution generates health bene ts in terms of the expected averted premature deaths due to air pollution declines. In general, the evidence that COVID-19 outbreaks have reduced levels of air pollution and detrimental effects of polluted environment on human health is now rarely contested.…”