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Unbalanced emission reductions of different species and sectors in Chinaduring COVID-19 lockdown derived by multi-species surface observationassimilation
Journal article   Open access   Peer reviewed

Unbalanced emission reductions of different species and sectors in Chinaduring COVID-19 lockdown derived by multi-species surface observationassimilation

Lei Kong, Xiao Tang, Jiang Zhu, Zifa Wang, Yele Sun, Pingqing Fu, Meng Gao, Huangjian Wu, Miaomiao Lu, Qian Wu, …
Atmospheric chemistry and physics, Vol.23(11), pp.6217-6240
06/07/2023
DOI: 10.5194/acp-23-6217-2023
url
https://doi.org/10.5194/acp-23-6217-2023View
Published (Version of record) Open Access

Abstract

The unprecedented lockdown of human activities during the COVID-19 pandemic has significantly influenced social life in China. However, understanding the impact of this unique event on the emissions of different species is still insufficient, prohibiting the proper assessment of the environmental impacts of COVID-19 restrictions. Here we developed a multi-air-pollutant inversion system to simultaneously estimate the emissions of NOx, SO2, CO, PM2.5 and PM10 in China during COVID-19 restrictions with high temporal (daily) and horizontal (15 km) resolutions. Subsequently, contributions of emission changes versus meteorological variations during the COVID-19 lockdown were separated and quantified. The results demonstrated that the inversion system effectively reproduced the actual emission variations in multi-air pollutants in China during different periods of COVID-19 lockdown, which indicate that the lockdown is largely a nationwide road traffic control measure with NOx emissions decreasing substantially by similar to 40 %. However, emissions of other air pollutants were found to only decrease by similar to 10% because power generation and heavy industrial processes were not halted during lockdown, and residential activities may actually have increased due to the stay-at-home orders. Consequently, although obvious reductions of PM2.5 concentrations occurred over the North China Plain (NCP) during the lockdown period, the emission change only accounted for 8.6% of PM2.5 reductions and even led to substantial increases in O-3. The meteorological variation instead dominated the changes in PM2.5 concentrations over the NCP, which contributed 90% of the PM2.5 reductions over most parts of the NCP region. Meanwhile, our results suggest that the local stagnant meteorological conditions, together with inefficient reductions of PM2.5 emissions, were the main drivers of the unexpected PM2.5 pollution in Beijing during the lockdown period. These results highlighted that traffic control as a separate pollution control measure has limited effects on the coordinated control of O-3 and PM2.5 concentrations under current complex air pollution conditions in China. More comprehensive and balanced regulations for multiple precursors from different sectors are required to address O-3 and PM2.5 pollution in China.
 Physical Sciences Environmental Sciences Environmental Sciences & Ecology Life Sciences & Biomedicine Meteorology & Atmospheric Sciences Science & Technology

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