Tao Jun, Zhang Zhisheng, Zhang Leiming, Li Jiawei, Wu Yunfei, Pei Chenglei, Nie Fuli
Institute for Environmental and Climate Research, Jinan University, Guangzhou, China; South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou, China.
South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou, China; Guangdong Provincial Observation and Research Station for Climate Environment and Air Quality Change in the Pearl River Estuary, Guangzhou, China.
Chemosphere. 2022 Aug;300:134598. doi: 10.1016/j.chemosphere.2022.134598. Epub 2022 Apr 14.
To identify potential formation mechanisms of water-soluble organic carbon (WSOC) and quantify their contributions to WSOC in urban Guangzhou of south China, a comprehensive campaign was carried out in winter of 2019-2020. During the campaign, WSOC, total carbon (TC), black carbon (BC), water-soluble inorganic ions (WSIIs) and fourteen elements in PM were collected using inline instruments. Bulk PM and size-segregated particle samples were also synchronously collected using offline instruments for analyzing the dominant chemical components including WSOC, organic carbon (OC), elemental carbon (EC) and WSIIs. In addition, gaseous pollutants (e.g., NH, SO, HNO, NO, O) and meteorological parameters were also measured during the same period. PM pollution episodes during the campaign period were mainly driven by increased nitrate concentrations. The mass concentration of WSOC increased from 3.9 ± 1.1 μg m on non-episode days to 6.8 ± 0.6 μg m on episode days, although the mass ratio of WSOC to OC in PM changed little (<4%). Photochemical processes dominated WSOC formation in the afternoon and aqueous phase chemical processes played the dominant role in the night, from which newly formed WSOC distributed in the condensation mode and the droplet mode, respectively. Source apportionment analysis using positive matrix factorization (PMF) model suggested that on average 35% and 65% of WSOC mass in PM were related with the photochemical processes and aqueous phase chemical processes, respectively. Aqueous phase chemical processes were highly affected by nitrate pollution, which was closely related with O pollution.
为了确定水溶性有机碳（WSOC）的潜在形成机制，并量化其对中国南方广州市城区WSOC的贡献，于2019年至2020年冬季开展了一项综合监测活动。在监测期间，使用在线仪器收集了WSOC、总碳（TC）、黑碳（BC）、水溶性无机离子（WSIIs）和PM中的14种元素。还使用离线仪器同步采集了大气颗粒物（PM）总量和粒径分级的颗粒物样本，以分析包括WSOC、有机碳（OC）、元素碳（EC）和WSIIs在内的主要化学成分。此外，同期还测量了气态污染物（如NH₃、SO₂、HNO₃、NO₂、O₃）和气象参数。监测期间的PM污染事件主要由硝酸盐浓度增加所致。尽管PM中WSOC与OC的质量比变化不大（<4%），但WSOC的质量浓度从非污染日的3.9±1.1 μg/m³增加到污染日的6.8±0.6 μg/m³。光化学过程在下午主导了WSOC的形成，而水相化学过程在夜间起主导作用，新形成的WSOC分别以凝聚模态和液滴模态分布。使用正定矩阵因子分解（PMF）模型的源解析分析表明，PM中WSOC质量平均分别有35%和65%与光化学过程和水相化学过程有关。水相化学过程受硝酸盐污染的影响很大，而硝酸盐污染与O₃污染密切相关。
