Measurement report: The importance of biomass burning in light extinction and direct radiative effect of urban aerosol during the COVID-19 lockdown in Xi'an, China

<p>Due to the complexity of emission sources, a better understanding of aerosol optical properties is required to mitigate climate change in China. Here, an intensive real-time measurement campaign was conducted in an urban area of China before and during the COVID-19 lockdown in order to expl...

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Main Authors: J. Tian, Q. Wang, H. Liu, Y. Ma, S. Liu, Y. Zhang, W. Ran, Y. Han, J. Cao
Format: Article
Language:English
Published: Copernicus Publications 2022-06-01
Series:Atmospheric Chemistry and Physics
Online Access:https://acp.copernicus.org/articles/22/8369/2022/acp-22-8369-2022.pdf
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author J. Tian
J. Tian
Q. Wang
Q. Wang
Q. Wang
H. Liu
Y. Ma
S. Liu
S. Liu
Y. Zhang
W. Ran
Y. Han
Y. Han
Y. Han
J. Cao
author_facet J. Tian
J. Tian
Q. Wang
Q. Wang
Q. Wang
H. Liu
Y. Ma
S. Liu
S. Liu
Y. Zhang
W. Ran
Y. Han
Y. Han
Y. Han
J. Cao
author_sort J. Tian
collection DOAJ
description <p>Due to the complexity of emission sources, a better understanding of aerosol optical properties is required to mitigate climate change in China. Here, an intensive real-time measurement campaign was conducted in an urban area of China before and during the COVID-19 lockdown in order to explore the impacts of anthropogenic activities on aerosol light extinction and the direct radiative effect (DRE). The mean light extinction coefficient (<span class="inline-formula"><i>b</i><sub>ext</sub></span>) decreased from 774.7 <span class="inline-formula">±</span> 298.1 Mm<span class="inline-formula"><sup>−1</sup></span> during the normal period to 544.3 <span class="inline-formula">±</span> 179.4 Mm<span class="inline-formula"><sup>−1</sup></span> during the lockdown period. A generalised additive model analysis indicated that the large decline in <span class="inline-formula"><i>b</i><sub>ext</sub></span> (29.7 %) was due to sharp reductions in anthropogenic emissions. Chemical calculation of <span class="inline-formula"><i>b</i><sub>ext</sub></span> based on a ridge regression analysis showed that organic aerosol (OA) was the largest contributor to <span class="inline-formula"><i>b</i><sub>ext</sub></span> in both periods (45.1 %–61.4 %), and the contributions of two oxygenated OAs to <span class="inline-formula"><i>b</i><sub>ext</sub></span> increased by 3.0 %–14.6 % during the lockdown. A hybrid environmental receptor model combined with chemical and optical variables identified six sources of <span class="inline-formula"><i>b</i><sub>ext</sub></span>. It was found that <span class="inline-formula"><i>b</i><sub>ext</sub></span> from traffic-related emissions, coal combustion, fugitive dust, the nitrate and secondary OA (SOA) source, and the sulfate and SOA source decreased by 21.4 %–97.9 % in the lockdown, whereas <span class="inline-formula"><i>b</i><sub>ext</sub></span> from biomass burning increased by 27.1 %, mainly driven by the undiminished need for residential cooking and heating. An atmospheric radiative transfer model was further used to illustrate that biomass burning, rather than traffic-related emissions, became the largest positive effect (10.0 <span class="inline-formula">±</span> 10.9 W m<span class="inline-formula"><sup>−2</sup></span>) on aerosol DRE in the atmosphere during the lockdown. Our study provides insights into aerosol <span class="inline-formula"><i>b</i><sub>ext</sub></span> and DRE from anthropogenic sources, and the results imply the importance of controlling biomass burning for tackling climate change in China in the future.</p>
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spelling doaj.art-264d6c6df9fa41ad9db2cd1cfd0e67b72022-12-22T03:33:15ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242022-06-01228369838410.5194/acp-22-8369-2022Measurement report: The importance of biomass burning in light extinction and direct radiative effect of urban aerosol during the COVID-19 lockdown in Xi'an, ChinaJ. Tian0J. Tian1Q. Wang2Q. Wang3Q. Wang4H. Liu5Y. Ma6S. Liu7S. Liu8Y. Zhang9W. Ran10Y. Han11Y. Han12Y. Han13J. Cao14Key Laboratory of Aerosol Chemistry and Physics, State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, ChinaCAS Center for Excellence in Quaternary Science and Global Change, Xi'an 710061, ChinaKey Laboratory of Aerosol Chemistry and Physics, State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, ChinaCAS Center for Excellence in Quaternary Science and Global Change, Xi'an 710061, ChinaNational Observation and Research Station of Regional Ecological Environment Change and Comprehensive Management in the Guanzhong Plain, Shaanxi, Xi'an 710061, ChinaKey Laboratory of Aerosol Chemistry and Physics, State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, ChinaMeteorological Institute of Shaanxi Province, Xi'an 710015, ChinaKey Laboratory of Aerosol Chemistry and Physics, State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, ChinaCAS Center for Excellence in Quaternary Science and Global Change, Xi'an 710061, ChinaKey Laboratory of Aerosol Chemistry and Physics, State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, ChinaKey Laboratory of Aerosol Chemistry and Physics, State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, ChinaKey Laboratory of Aerosol Chemistry and Physics, State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, ChinaCAS Center for Excellence in Quaternary Science and Global Change, Xi'an 710061, ChinaNational Observation and Research Station of Regional Ecological Environment Change and Comprehensive Management in the Guanzhong Plain, Shaanxi, Xi'an 710061, ChinaInstitute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China<p>Due to the complexity of emission sources, a better understanding of aerosol optical properties is required to mitigate climate change in China. Here, an intensive real-time measurement campaign was conducted in an urban area of China before and during the COVID-19 lockdown in order to explore the impacts of anthropogenic activities on aerosol light extinction and the direct radiative effect (DRE). The mean light extinction coefficient (<span class="inline-formula"><i>b</i><sub>ext</sub></span>) decreased from 774.7 <span class="inline-formula">±</span> 298.1 Mm<span class="inline-formula"><sup>−1</sup></span> during the normal period to 544.3 <span class="inline-formula">±</span> 179.4 Mm<span class="inline-formula"><sup>−1</sup></span> during the lockdown period. A generalised additive model analysis indicated that the large decline in <span class="inline-formula"><i>b</i><sub>ext</sub></span> (29.7 %) was due to sharp reductions in anthropogenic emissions. Chemical calculation of <span class="inline-formula"><i>b</i><sub>ext</sub></span> based on a ridge regression analysis showed that organic aerosol (OA) was the largest contributor to <span class="inline-formula"><i>b</i><sub>ext</sub></span> in both periods (45.1 %–61.4 %), and the contributions of two oxygenated OAs to <span class="inline-formula"><i>b</i><sub>ext</sub></span> increased by 3.0 %–14.6 % during the lockdown. A hybrid environmental receptor model combined with chemical and optical variables identified six sources of <span class="inline-formula"><i>b</i><sub>ext</sub></span>. It was found that <span class="inline-formula"><i>b</i><sub>ext</sub></span> from traffic-related emissions, coal combustion, fugitive dust, the nitrate and secondary OA (SOA) source, and the sulfate and SOA source decreased by 21.4 %–97.9 % in the lockdown, whereas <span class="inline-formula"><i>b</i><sub>ext</sub></span> from biomass burning increased by 27.1 %, mainly driven by the undiminished need for residential cooking and heating. An atmospheric radiative transfer model was further used to illustrate that biomass burning, rather than traffic-related emissions, became the largest positive effect (10.0 <span class="inline-formula">±</span> 10.9 W m<span class="inline-formula"><sup>−2</sup></span>) on aerosol DRE in the atmosphere during the lockdown. Our study provides insights into aerosol <span class="inline-formula"><i>b</i><sub>ext</sub></span> and DRE from anthropogenic sources, and the results imply the importance of controlling biomass burning for tackling climate change in China in the future.</p>https://acp.copernicus.org/articles/22/8369/2022/acp-22-8369-2022.pdf
spellingShingle J. Tian
J. Tian
Q. Wang
Q. Wang
Q. Wang
H. Liu
Y. Ma
S. Liu
S. Liu
Y. Zhang
W. Ran
Y. Han
Y. Han
Y. Han
J. Cao
Measurement report: The importance of biomass burning in light extinction and direct radiative effect of urban aerosol during the COVID-19 lockdown in Xi'an, China
Atmospheric Chemistry and Physics
title Measurement report: The importance of biomass burning in light extinction and direct radiative effect of urban aerosol during the COVID-19 lockdown in Xi'an, China
title_full Measurement report: The importance of biomass burning in light extinction and direct radiative effect of urban aerosol during the COVID-19 lockdown in Xi'an, China
title_fullStr Measurement report: The importance of biomass burning in light extinction and direct radiative effect of urban aerosol during the COVID-19 lockdown in Xi'an, China
title_full_unstemmed Measurement report: The importance of biomass burning in light extinction and direct radiative effect of urban aerosol during the COVID-19 lockdown in Xi'an, China
title_short Measurement report: The importance of biomass burning in light extinction and direct radiative effect of urban aerosol during the COVID-19 lockdown in Xi'an, China
title_sort measurement report the importance of biomass burning in light extinction and direct radiative effect of urban aerosol during the covid 19 lockdown in xi an china
url https://acp.copernicus.org/articles/22/8369/2022/acp-22-8369-2022.pdf
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