银川市PM2.5的输送路径及潜在源解析

基于2015~2017年银川市PM_2.5逐小时质量浓度和同期气象数据，采用气流后向轨迹聚类分析法、潜在来源贡献函数法（PSCF）和浓度权重轨迹分析法（CWT）研究银川市PM_2.5的输送路径及潜在源分布.结果表明：2013~2018年银川市大气PM_2.5质量浓度呈先升高后下降的趋势，其中2016年PM_2.5浓度年均值最高（54.25±20.91）μg/m³；在四季变化中，冬季PM_2.5浓度最高（75.11±29.21）μg/m³，夏季最低（31.83±7.09）μg/m³.聚类分析表明西北方向气流是银川市四季PM_2.5主要的输送路径，在春、秋、冬3季PM_2.5均为西北长距离输送路径；而在夏季，短距离输送气流是PM_2.5主要的输送方式.PSCF与CWT分析表明，冬季PM_2.5潜在源区范围最大，主要集中在西北-东南走向的潜在贡献源区带，包括新疆中东部、青海省北部、河西走廊地区、内蒙古西南部、甘肃省南部以及宁夏西北部；春、秋两季PM_2.5潜在源区主要位于新疆东部与甘肃省交界区域、甘肃省东南部、湖北北部、陕西西南部以及重庆北部；夏季的潜在源区范围最小，主要集中在新疆东部与甘肃交界区域.在PM_2.5重污染天气期间，其主要来源于西北方向气流，潜在源区主要分布在新疆东部与甘肃交界区域、内蒙古西南部与甘肃交界区域以及甘肃中南部地区.因此，在实施防风固沙的基础上，加强区域环境合作，实施大气污染联合防治，可以有效缓解银川乃至京津冀地区的大气污染.

The transport pathways and potential source regions of PM2.5 in Yinchuan,China

The transport pathways and potential sources of PM_2.5 in Yinchuan City from 2015 to 2017 were investigated by backward trajectory clustering analysis, potential source contribution function (PSCF) and concentration weighted trajectory analysis (CWT) method, based on PM_2.5 hourly mass concentration and meteorological data in Yinchuan City from 2015 to 2017. The mass concentration of PM_2.5 trend in Yinchuan City firstly increased with the highest value of (54.25±20.91)μg/m³ in 2016, and then decreased from 2013 to 2018. The highest PM_2.5 concentration occurred in winter (75.11±29.21)μg/m³ and the lowest value showed in summer (31.83±7.09)μg/m³ among the four seasons. The major transport pathways were from the northwest of Yinchuan City for all seasons. The long-distance transportation of air masses mostly occurred in spring, autumn and winter, while the short-distance transportation of air masses was the main pathway in summer. PSCF and CWT showed that northwest and southeast channels were the largest potential source regions of PM_2.5 in winter, including the central and eastern Xinjiang, Northern Qinghai Province, Hexi Corridor Area, southwestern Inner Mongolia, southern Gansu Province and northwestern Ningxia. The main potential source regions in spring and autumn located in the border area between eastern Xinjiang and Gansu Province, the southeastern of Gansu Province, Northern Hubei, southwestern Shaanxi and northern Chongqing. The potential source region of PM_2.5 in Yinchuan was the smallest in summer, mainly in eastern Xinjiang and the Gansu border area. During the heavy pollution period, the main transport paths of PM_2.5 came from the northwest and the potential source regions were mainly located in eastern Xinjiang and Gansu border, southwestern Inner Mongolia and Gansu border, and the central and southern Gansu Province. Therefore, on the basis of wind prevention and sand fixation measures, enhancing regional environmental cooperation and pollution control are effective air pollution measures to alleviate Yinchuan as well as Beijing-Tianjin-Hebei region.