State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences (CAS), Lanzhou, 73000, China.
State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences (CAS), Lanzhou, 73000, China.
Environ Pollut. 2019 Feb;245:519-530. doi: 10.1016/j.envpol.2018.11.027. Epub 2018 Nov 13.
To mitigate severe wintertime pollution events in Western China, identifying the source of atmospheric fine particles with an aerodynamic diameter of ≤2.5 μm (PM) is a crucial step. In this study, we first analyzed the meteorological and emission factors that caused a considerable increase in the PM concentration in December 2016. This severe pollution episode was found to be related with unfavorable meteorological conditions and increased residential emissions. The WRF-Chem simulations were used to calculate the residential contribution to PM through a hybrid source apportionment method. From the validation that used grid data and in situ observations in terms of meteorological elements, PM and its compounds, the simulated results indicated that the residential sector was the largest single contributor to the PM concentration (60.2%), because of its predominant contributions to black carbon (BC, 62.1%) and primary organic aerosol (POA, 86.5%), with these two primary components accounting for 70.7% of the PM mass. Compared with the remote background (RB) region covering the central part of the Tibetan Plateau, the residential sector contributed 11.3% more to PM in the highly populated mega-city (HM) region, including the Sichuan and Guanzhong Basins, due to greater contribution to the concentrations of primary PM components. As the main emission source of sulfur dioxide (SO), nitrogen oxides (NO), and secondary organic aerosol (SOA), the industrial sector was the second largest contributor to the PM concentration in the HM region. However, in the RB region, the dominating emissions of NO, SOA, and BC were from the transport sector; thus, it was the next largest contributor to total PM. An evaluation of the emission control experiment suggested that mitigation strategies that reduce emissions from residential sources can effectively reduce the PM concentration during heavy pollution periods.
为了缓解中国西部冬季严重的污染事件，识别大气中直径≤2.5μm 的细颗粒物（PM）的来源是至关重要的一步。在本研究中，我们首先分析了导致 2016 年 12 月 PM 浓度显著增加的气象和排放因子。发现这次严重的污染事件与不利的气象条件和增加的居民排放有关。WRF-Chem 模拟使用混合源分配方法计算了居民对 PM 的贡献。通过对气象要素、PM 及其化合物的网格数据和现场观测进行验证，模拟结果表明，居民部门是 PM 浓度的最大单一贡献者（60.2%），因为其对黑碳（BC，62.1%）和一次有机气溶胶（POA，86.5%）的主要贡献，这两种主要成分占 PM 质量的 70.7%。与覆盖青藏高原中部的偏远背景（RB）地区相比，包括四川和关中盆地在内的人口众多的特大城市（HM）地区的居民部门对 PM 的贡献增加了 11.3%，这是由于对一次 PM 成分浓度的贡献更大。作为二氧化硫（SO）、氮氧化物（NO）和二次有机气溶胶（SOA）的主要排放源，工业部门是 HM 地区 PM 浓度的第二大贡献者。然而，在 RB 地区，NO、SOA 和 BC 的主要排放源是交通部门；因此，它是总 PM 的下一个最大贡献者。对排放控制实验的评估表明，减少居民源排放的缓解策略可以有效地降低重污染期间的 PM 浓度。
