熊健,冯徽徽,丁莹,欧菲菲,肖静怡,胡夙廷.长沙地区PM2.5传输路径和潜在源区时空分析[J].环境科学学报,2021,41(9):3663-3672
长沙地区PM2.5传输路径和潜在源区时空分析
- Spatial and temporal analysis of PM2.5 transmission paths and potential sources regions in Changsha Region
- 基金项目：国家自然科学基金（No.42071378）；湖南省自然科学基金优秀青年项目（No.2020JJ3045）；湖南省自然科学基金面上项目（No.2018JJ2498）
- 熊健
- 中南大学地球科学与信息物理学院, 长沙 410083
- 冯徽徽
- 中南大学地球科学与信息物理学院, 长沙 410083
- 丁莹
- 中南大学地球科学与信息物理学院, 长沙 410083
- 欧菲菲
- 中南大学地球科学与信息物理学院, 长沙 410083
- 肖静怡
- 中南大学地球科学与信息物理学院, 长沙 410083
- 胡夙廷
- 中南大学地球科学与信息物理学院, 长沙 410083
- 摘要：长沙地区是长江中下游重要的经济发展核心区，受本地排放与外来源输送等多因素的共同作用，其大气污染状况一直都是区域乃至国家高度重视的生态环境问题.前期研究揭示了长沙地区大气污染的扩散规律，为进一步研究该地区大气细颗粒物（PM2.5）外来源特征，采用拉格朗日混合型单粒子轨迹模式（HYSPLIT）探究2013—2020年长沙地区PM2.5外来源区分布特征，继而采用轨迹聚类、潜在源贡献因子分析（PSCF）、浓度权重轨迹（CWT）方法等从年、季节等不同尺度分析区域PM2.5时空分布规律及其外来污染物输送源特征.结果表明，在国家与地区大气污染联防联控等政策的驱动下，2013—2020年长沙地区年均PM2.5浓度由81.80 μg·m-3下降至42.96 μg·m-3并呈显著季节差异，大气污染防治措施成效显著.季节尺度上，PM2.5浓度主要呈现冬高夏低的态势，冬季最高（81.48 μg·m-3），其次为秋季（50.90 μg·m-3）与春季（47.39 μg·m-3），最小值出现在夏季（25.74 μg·m-3）；另一方面，2013—2020年长沙地区外来源潜在源区主要分布于湘东北、赣西北、豫南和鄂中地区.具体而言，春、秋、冬三季大气污染物主要来源于蒙古国西南部的长距离西北气流，分别占当年轨迹比重的4.73%、12.93%、12.66%，而夏季大气污染物主要来源于南海南部的中长距离南方气流，占当年轨迹比重的19.06%.
- Abstract：Changsha is a crucial economic development core in the middle and lower Yangtze River that suffers from severe air pollution due to the combined effects of local emissions and external source transport. This issue has received increasing attention from the regional and central governments. Our previous study had explored the characteristics of air pollution dispersion in Changsha region that is critical to curb the air pollution. This study further evaluated the characteristics of external sources of fine particulate matter (PM2.5) through the Hybrid Single-Particle Lagrangian Integrated Trajectory Model (HYSPLIT) from 2013 to 2020. Then we analyzed the spatial and temporal patterns of the external sources using the trajectory clustering, potential source contribution factor analysis (PSCF) and concentration weight trajectory (CWT) methods at annual and seasonal scales. Results show that the annual average PM2.5 in Changsha decreases from 81.80 μg·m-3 to 42.96 μg·m-3 from 2013 to 2020 due to the national and regional environmental policies. At the seasonal scale, PM2.5 pollution concentration is highest in winter (81.48 μg·m-3), followed by autumn (50.90 μg·m-3) and spring (47.39 μg·m-3), and lowest value occurs in summer (25.74 μg·m-3). The external sources for the air pollution in Changsha mainly locate in northeastern Hunan, northwestern Jiangxi, southern Henan, and central Hubei. Specifically, the air pollutants in spring, autumn and winter mainly originate from the long-range northwest air flow in southwest Mongolia, accounting for 4.73%, 12.93% and 12.66% of the trajectory proportion of the year, respectively. By contrast, the air pollutants in summer are mainly from the medium-range south air flow in south of the South China ocean (accounting for 19.06% of the total annual trajectory proportion).
