Impact of COVID-19 related containment measures on air pollution
The response to the COVID-19 outbreak has resulted in one of the largest short-term declines in anthropogenic emissions in modern history. To date, there has not been a comprehensive assessment of the impact of the blockade on air quality and human health. Using global satellite observations and ground measurements from 36 countries in Europe, North America, and East Asia, we find that the blockade has reduced NO 2 concentrations globally and averted about 32,000 premature deaths, including about 21,000 in China. However, there is no corresponding reduction in PM2.5 and ozone globally. Using satellite measurements, we show that the cutoff between NO 2 ozone changes is due to regional chemical regimes; COVID-related blockades indicate the need for targeted air quality policies to reduce the global burden of air pollution, especially related to secondary pollutants.
Science Advances, May 21, 2021:.Vol. 7, No. 21, eabe1178
DOI: 10.1126 / sciadv.abe1178
Commentary
A report on the impact of urban blockades on air pollution in each region was presented, along with estimates of early mortality in each region.
The impact of the urban blockade on air pollution in each region is statistically significant at the 5% level in 120 regions, representing 70% of the population. This shows that the null hypothesis that there was no change in the level of ambient air pollution due to the increase in stringency index can be rejected with 95% confidence level.
In light of these results, we calculate the average difference between the modeled counterfactual and the observed NO 2 exposure during the lockdown period in each region, the decrease is largest in China, and the population-weighted change in NO 2 concentrations averages -16 μgm, a -53% change compared to the counterfactual.
From the start of the average NO 2 local lockdown to July 6, 2020, concentrations changed by -25% in Korea, -24% in Europe, -8.6% in Japan, and -4.3% in the United States. Of the 252 regions analyzed by the ground monitoring method, 222 showed a decrease in NO 2 levels in response to more severe urban blockades.
As for changes in early mortality related to air pollution.
overall pollutants based on monitoring data, we find that the urban blockade and changes in pollutant concentrations associated with COVID-19 through July 6, 2020 resulted in -95,000 early deaths from NO 2, PM 2.5, and ozone For exposures during the lockdown period, statistically significant changes in air pollution at the 5% level contributed to -67,000 all premature deaths and, for comparison, 544,000 COVID-19 global deaths as of July 6, 2020. The reduction in early mortality per capita associated with air pollution is less than 2.8% of deaths per capita due to COVID-19 in the United States and 6.4%, but 2.3-16 times the number of deaths per capita due to COVID-19 reported in Asia.
Conclusion
This study shows that there is a relationship between the severity of urban blockades and air pollution, and the early mortality rates caused by these factors. However, the figures differ from country to country depending on the status of urban blockades and other factors, so it is not easy to say that the early mortality rates are decreasing due to the effects of urban blockades.
In areas where pollution is more severe, such as large urban areas, these effects were more likely to be observed, suggesting that air pollution and daily activities need to be reviewed.
