Lu Miaomiao, Tang Xiao, Wang Zifa, Gbaguidi Alex, Liang Shengwen, Hu Ke, Wu Lin, Wu Huangjian, Huang Zhen, Shen Longjiao
LAPC, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Science, Beijing, China.
LAPC, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China.
Environ Pollut. 2017 Dec;231(Pt 1):612-621. doi: 10.1016/j.envpol.2017.08.046. Epub 2017 Aug 29.
Wuhan as a megacity of Central China was suffering from severe particulate matter pollution according to previous observation studies, however, the mechanism behind the pollution formation especially the impact of regional chemical transport is still unclear. This study, carried out on the Nested Air Quality Prediction Modeling System (NAQPMS) coupled with an on-line source-tagging module, explores different roles regional transport had in two strong haze episodes over Wuhan in October 2014 and quantitatively assesses the contributions from local and regional sources to PM concentration. Validation of predictions based on observations shows modeling system good skills in reproducing key meteorological and chemical features. The first short-time haze episode occurred on 12 October under strong northerly winds, with a hourly PM peak of 180 μg m, and was found to be caused primarily by the long-range transport from the northern regions, which contributed 60.6% of the episode's PM concentration (versus a total of 32.7% from sources in and near Wuhan). The second episode lasted from the 15-20 October under stable regional large-scale synoptic conditions and weak winds, and had an hourly PM peak of 231.0 μg m. In this episode, both the long-distance transport from far regions and short-range transport from the Wuhan-cluster were the primary causes of the haze episode and account for 24.8% and 29.2% of the PM concentration respectively. Therefore, regional transport acts as a crucial driver of haze pollution over Wuhan through not only long-range transfer of pollutants, but also short-range aerosol movement under specific meteorological conditions. The present findings highlight the important role of regional transport in urban haze formation and indicate that the joint control of multi city-clusters are needed to reduce the particulate pollution level in Wuhan.
根据以往的观测研究,作为中国中部的特大城市,武汉正遭受严重的颗粒物污染,然而,污染形成背后的机制,尤其是区域化学传输的影响仍不清楚。本研究基于嵌套空气质量预测模型系统(NAQPMS)并结合在线源标记模块开展,探讨了区域传输在2014年10月武汉两次强霾事件中所起的不同作用,并定量评估了本地和区域源对颗粒物浓度的贡献。基于观测的预测验证表明,该模型系统在再现关键气象和化学特征方面具有良好的技能。第一次短时霾事件于10月12日在强劲北风下发生,每小时颗粒物峰值为180μg/m³,发现主要是由北方地区的远距离传输造成的,该传输对该事件颗粒物浓度的贡献为60.6%(而武汉及其附近源的贡献总计为32.7%)。第二次事件从10月15日持续至20日,处于稳定的区域大尺度天气条件和弱风环境下,每小时颗粒物峰值为231.0μg/m³。在这次事件中,远距离的远距离传输和武汉城市群的短距离传输都是霾事件的主要成因,分别占颗粒物浓度的24.8%和29.2%。因此,区域传输不仅通过污染物的远距离传输,还通过特定气象条件下的短距离气溶胶移动,成为武汉霾污染的关键驱动因素。本研究结果突出了区域传输在城市霾形成中的重要作用,并表明需要多城市群联合控制以降低武汉的颗粒物污染水平。