Global air quality change during COVID-19: a synthetic analysis of satellite, reanalysis and ground station data

Yang, Qianqian Wang Bin Wang Yuan Yuan Qiangqiang Jin Caiyi Wang Jiwen Li Shuwen Li Muyu Li Tongwen Liu Song Shen Huanfeng Zhang Liangpei

Coronavirus disease 2019 (COVID-19) pandemic has led to a rare reduction in human activities. In such a background, data from ground-based environmental stations, satellites, and reanalysis materials are utilized to conduct a comprehensive analysis of the global air quality changes during the COVID-19 outbreak. The results showed that under the impact of the COVID-19 outbreak, a significant decrease in particulate matter (PM x ) and nitrogen dioxide (NO2) occurred in more than 40% of the world’s land area, with NO2 (PM x ) decreasing by ∼30% (∼20%). The mobility, meteorological factors, and the response speed to COVID-19 outbreaks were examined. It was further found that in quick-response cities, lockdowns produced a sharp decline in mobility and had a dominant impact on air quality. In contrast, in slow-response cities, mobility dropped gradually since the confirmation of the first COVID-19 case (FCC) and he impact of the FCC, lockdowns, and meteorological factors were comparable.