Impacts of COVID-19 on Air Quality over China: Links with Meteorological Factors and Energy Consumption

Abstract

The stringent control measures in China to curb the spread of Coronavirus disease have had profound societal and environmental impacts, including changes in energy consumption practices and thereby in air pollutant emissions. In this study, a suite of satellite and numerically assimilated air pollution and meteorological data combined with information on energy consumption practices and nighttime light (NTL) was used to evaluate the effects of these COVID-19 control measures on air quality. These data revealed that control measures reduced aerosols mostly over central and eastern parts of China by countering favorable meteorological conditions for increased aerosols. The control measures reduced short-lived nitrogen dioxide (NO 2 ) with little influence on long-lived carbon monoxide (CO). Consistent with energy production and energy consumption statistics in different sectors, NTL data suggest that high human mobility within the residential sector and reduced activity in other sectors during the implementation of control measures explain small but significant decreases in black carbon and sulfate aerosols, respectively, during this period. Overall, these results provide useful information for policy makers and the scientific community by clarifying the contributions of meteorological factors and energy consumption to changes in air quality. This information can guide the development of air pollution mitigation strategies and provides insight into the air pollution status in China and the potential for long-distance transport.

Abrupt emission reduction during COVID-19 intensified the spring 2020 rainfall over India

“…Changes in aerosol field emission caused by the lockdown could have had an impact on radiation and cloud characteristics (Timmermann et al, 2020;Khatri and Hayasaka, 2021). Here, we show changes in cloud parameters in response to aerosol changes during the lockdown period.…”

“…The study also highlighted that the impact of aerosol are stonger over GHGs on change in precipitation. Hence, we suggest detailed modelling studies, which may shed further light on the link between aerosol reduction and associated regional climatic effects (Khatri et al, 2021).…”

“…From our model simulations, the changes in cloud parameters in 2020 (C19-CTL) indicate the response of clouds to anthropogenic emission reduction (Figure 2). It is well known that in the presence of an anomalous increase in aerosol loading, cloud invigoration may take place, i.e., in response to increased aerosol number concentration; there can be a decrease in cloud-droplet size (Rosenfeld et al, 2014;Zhao et al, 2018;Khatri et al, 2021). This may further lead to vertical cloud growth and conversion of a water cloud into an ice cloud.…”

Aerosol Loading and Radiation Budget Perturbations in Densely Populated and Highly Polluted Indo‐Gangetic Plain by COVID‐19: Influences on Cloud Properties and Air Temperature

“…The dense population can result regional high AOD (Ramachandran & Cherian, 2008 ; Wang et al., 2017 ). Recent studies (e.g., Bonardi et al., 2021 ; Khatri & Hayasaka, 2021 ) showed a weak influence of lockdown measures on household air pollutant reduction, suggesting that such high AOD could be possible over densely populated IGP even without active emissions from commercial and transportation sectors. As there was decrease in AOD over upwind regions during lockdown period (Pandey & Vinoj, 2021 ), such high AODs were less likely due to the effects of human activities of upwind regions.…”

Improvement of Air Quality during the COVID-19 Lockdowns in the Republic of Slovenia and its Connection with Meteorology

“…Meteorological variables including temperature, humidity, wind speed, and wind direction greatly impact particulate concentrations in the atmosphere (Khatri and Hayasaka, 2021;Zhu et al, 2020). As stated, the wind conditions in the RS are influenced by its varied relief, location and the Alps.…”