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Changes in physical and chemical properties of urban atmospheric aerosols and ozone during the COVID-19 lockdown in a semi-arid region
The synergistic response of urban atmospheric aerosols and ozone (O(3)) to reduction of anthropogenic emissions is complicated and still needs further study. Thus, the changes in physical and chemical properties of urban atmospheric aerosols and O(3) during the Coronavirus Disease 2019 (COVID-19) lo...
Autores principales: | , , , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Elsevier Ltd.
2022
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9259058/ https://www.ncbi.nlm.nih.gov/pubmed/35818429 http://dx.doi.org/10.1016/j.atmosenv.2022.119270 |
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author | Chang, Yi Du, Tao Song, Xin Wang, Wenfang Tian, Pengfei Guan, Xu Zhang, Naiyue Wang, Min Guo, Yumin Shi, Jinsen Zhang, Lei |
author_facet | Chang, Yi Du, Tao Song, Xin Wang, Wenfang Tian, Pengfei Guan, Xu Zhang, Naiyue Wang, Min Guo, Yumin Shi, Jinsen Zhang, Lei |
author_sort | Chang, Yi |
collection | PubMed |
description | The synergistic response of urban atmospheric aerosols and ozone (O(3)) to reduction of anthropogenic emissions is complicated and still needs further study. Thus, the changes in physical and chemical properties of urban atmospheric aerosols and O(3) during the Coronavirus Disease 2019 (COVID-19) lockdown were investigated at three urban sites and one rural site in Lanzhou with semi-arid climate. Fine particulate matter (PM(2.5)) decreased at four sites by ∼ 20% while O(3) increased by >100% at two urban sites during the COVID-19 lockdown. Both primary emissions and secondary formation of PM(2.5) decreased during the lockdown. Significant increase in both sulfur and nitrogen oxidation ratios was found in the afternoon, which accounted for 48.7% of the total sulfate and 40.4% of the total nitrate, respectively. The positive matrix factorization source apportionment revealed increased contribution of secondary formation and decreased contribution of vehicle emissions. Aerosol scattering and absorption decreased by 33.6% and 45.3%, resulting in an increase in visibility by 30% and single scattering albedo (SSA) at 520 nm slightly increased by 0.02. The enhanced O(3) production was explained by increased volatile organic compounds to nitrogen oxides ratio, decreased aerosol, as well as increased SSA. The primary emissions of secondary aerosol precursors significantly decreased while Ox (i.e., NO(2) and O(3)) exhibited little change. Consequently, Ox to CO ratio, PM(2.5) to elemental carbon (EC) ratio, secondary inorganic aerosols to EC ratio, and secondary organic carbon to EC ratio increased, confirming enhanced secondary aerosol production efficiency during the lockdown. Positive feedback among O(3) concentration, secondary aerosol formation, and SSA was revealed to further promote O(3) production and secondary aerosol formation. These results provide scientific guidance for collaborative management of O(3) and particulate matter pollution for cities with semi-arid climate. |
format | Online Article Text |
id | pubmed-9259058 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2022 |
publisher | Elsevier Ltd. |
record_format | MEDLINE/PubMed |
spelling | pubmed-92590582022-07-07 Changes in physical and chemical properties of urban atmospheric aerosols and ozone during the COVID-19 lockdown in a semi-arid region Chang, Yi Du, Tao Song, Xin Wang, Wenfang Tian, Pengfei Guan, Xu Zhang, Naiyue Wang, Min Guo, Yumin Shi, Jinsen Zhang, Lei Atmos Environ (1994) Article The synergistic response of urban atmospheric aerosols and ozone (O(3)) to reduction of anthropogenic emissions is complicated and still needs further study. Thus, the changes in physical and chemical properties of urban atmospheric aerosols and O(3) during the Coronavirus Disease 2019 (COVID-19) lockdown were investigated at three urban sites and one rural site in Lanzhou with semi-arid climate. Fine particulate matter (PM(2.5)) decreased at four sites by ∼ 20% while O(3) increased by >100% at two urban sites during the COVID-19 lockdown. Both primary emissions and secondary formation of PM(2.5) decreased during the lockdown. Significant increase in both sulfur and nitrogen oxidation ratios was found in the afternoon, which accounted for 48.7% of the total sulfate and 40.4% of the total nitrate, respectively. The positive matrix factorization source apportionment revealed increased contribution of secondary formation and decreased contribution of vehicle emissions. Aerosol scattering and absorption decreased by 33.6% and 45.3%, resulting in an increase in visibility by 30% and single scattering albedo (SSA) at 520 nm slightly increased by 0.02. The enhanced O(3) production was explained by increased volatile organic compounds to nitrogen oxides ratio, decreased aerosol, as well as increased SSA. The primary emissions of secondary aerosol precursors significantly decreased while Ox (i.e., NO(2) and O(3)) exhibited little change. Consequently, Ox to CO ratio, PM(2.5) to elemental carbon (EC) ratio, secondary inorganic aerosols to EC ratio, and secondary organic carbon to EC ratio increased, confirming enhanced secondary aerosol production efficiency during the lockdown. Positive feedback among O(3) concentration, secondary aerosol formation, and SSA was revealed to further promote O(3) production and secondary aerosol formation. These results provide scientific guidance for collaborative management of O(3) and particulate matter pollution for cities with semi-arid climate. Elsevier Ltd. 2022-10-15 2022-07-06 /pmc/articles/PMC9259058/ /pubmed/35818429 http://dx.doi.org/10.1016/j.atmosenv.2022.119270 Text en © 2022 Elsevier Ltd. All rights reserved. Since January 2020 Elsevier has created a COVID-19 resource centre with free information in English and Mandarin on the novel coronavirus COVID-19. The COVID-19 resource centre is hosted on Elsevier Connect, the company's public news and information website. Elsevier hereby grants permission to make all its COVID-19-related research that is available on the COVID-19 resource centre - including this research content - immediately available in PubMed Central and other publicly funded repositories, such as the WHO COVID database with rights for unrestricted research re-use and analyses in any form or by any means with acknowledgement of the original source. These permissions are granted for free by Elsevier for as long as the COVID-19 resource centre remains active. |
spellingShingle | Article Chang, Yi Du, Tao Song, Xin Wang, Wenfang Tian, Pengfei Guan, Xu Zhang, Naiyue Wang, Min Guo, Yumin Shi, Jinsen Zhang, Lei Changes in physical and chemical properties of urban atmospheric aerosols and ozone during the COVID-19 lockdown in a semi-arid region |
title | Changes in physical and chemical properties of urban atmospheric aerosols and ozone during the COVID-19 lockdown in a semi-arid region |
title_full | Changes in physical and chemical properties of urban atmospheric aerosols and ozone during the COVID-19 lockdown in a semi-arid region |
title_fullStr | Changes in physical and chemical properties of urban atmospheric aerosols and ozone during the COVID-19 lockdown in a semi-arid region |
title_full_unstemmed | Changes in physical and chemical properties of urban atmospheric aerosols and ozone during the COVID-19 lockdown in a semi-arid region |
title_short | Changes in physical and chemical properties of urban atmospheric aerosols and ozone during the COVID-19 lockdown in a semi-arid region |
title_sort | changes in physical and chemical properties of urban atmospheric aerosols and ozone during the covid-19 lockdown in a semi-arid region |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9259058/ https://www.ncbi.nlm.nih.gov/pubmed/35818429 http://dx.doi.org/10.1016/j.atmosenv.2022.119270 |
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