AUTHOR=Zhang Hanyu , Wang Xuejun , Shen Xianbao , Li Xin , Wu Bobo , Chen Wenjing , Yao Zhiliang TITLE=Analysis of air pollution characteristics, transport pathways and potential source areas identification in Beijing before, during and after the COVID-19 outbreak JOURNAL=Frontiers in Environmental Science VOLUME=Volume 10 - 2022 YEAR=2022 URL=https://www.frontiersin.org/journals/environmental-science/articles/10.3389/fenvs.2022.982566 DOI=10.3389/fenvs.2022.982566 ISSN=2296-665X