Cause analysis of PM(2.5) pollution during the COVID-19 lockdown in Nanning, China.
Cause analysis of PM(2.5) pollution during the COVID-19 lockdown in Nanning, China.
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中国南宁市 COVID-19 封锁期间 PM2.5 污染原因分析
DOI：
10.1038/s41598-021-90617-5
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发表时间：
2021-05-27
影响因子：
4.6
通讯作者：
Wang S
中科院分区：
文献类型：
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作者：
Mo Z;Huang J;Chen Z;Zhou B;Zhu K;Liu H;Mu Y;Zhang D;Wang S
为了分析新冠肺炎疫情防控期间广西南宁市大气PM2.5污染的原因，在2020年2月18日至24日期间，利用单颗粒气溶胶质谱仪、大气浓度计和颗粒激光雷达，结合近地表气体污染物监测、气象条件、卫星遥感火点和反向轨迹模型。将雾霾分为三个阶段：污染前期（PPP）、污染积累期（PAP）和污染消散期（PDP）。PM2.5的主要来源是生物质燃烧（BB）（40.4%），其次是次级无机源（28.1%）和机动车尾气（11.7%）。PAP的特征是大量的次级无机源，占PM2.5总浓度的56.1%，其次是BB（17.4%）。购买力平价的吸收Ångström指数（2.2）高于其他两个时期。卫星遥感监测火点分析表明，南宁市周边地区露天BB可能是主要影响因素之一。采用行星边界层-相对湿度-二次颗粒物质-颗粒物质正反馈机制来解释大气过程。该研究强调了了解BB、二次无机源和气象在空气污染形成中的作用的重要性，并呼吁制定排放控制策略的政策。
To analyse the cause of the atmospheric PM2.5 pollution that occurred during the COVID-19 lockdown in Nanning, Guangxi, China, a single particulate aerosol mass spectrometer, aethalometer, and particulate Lidar coupled with monitoring near-surface gaseous pollutants, meteorological conditions, remote fire spot sensing by satellite and backward trajectory models were utilized during 18–24 February 2020. Three haze stages were identified: the pre-pollution period (PPP), pollution accumulation period (PAP) and pollution dissipation period (PDP). The dominant source of PM2.5 in the PPP was biomass burning (BB) (40.4%), followed by secondary inorganic sources (28.1%) and motor vehicle exhaust (11.7%). The PAP was characterized by a large abundance of secondary inorganic sources, which contributed 56.1% of the total PM2.5 concentration, followed by BB (17.4%). The absorption Ångström exponent (2.2) in the PPP was higher than that in the other two periods. Analysis of fire spots monitored by remote satellite sensing indicated that open BB in regions around Nanning City could be one of the main factors. A planetary boundary layer-relative humidity-secondary particle matter-particulate matter positive feedback mechanism was employed to elucidate the atmospheric processes in this study. This study highlights the importance of understanding the role of BB, secondary inorganic sources and meteorology in air pollution formation and calls for policies for emission control strategies.