• 关键词：大气颗粒物  PM_2.5  气象参数  后向轨迹  聚类分析  PSCF  CWT

• 基金项目：国家自然科学基金（No.91544218）；国家重点研发计划（No.2016YFF0103004，2017YFC0209504）；安徽省杰出青年科学基金（No.1808085J19）

• 杜朋
• 1. 中国科学院安徽光学精密机械研究所环境光学与技术重点实验室, 合肥 230031;2. 中国科学院大学, 北京 100049;3. 安徽省环境光学监测技术重点实验室, 合肥 230031

• 李德平
• 暨南大学信息科学技术学院, 广州 510632

• 刘建国
• 1. 中国科学院安徽光学精密机械研究所环境光学与技术重点实验室, 合肥 230031;2. 安徽省环境光学监测技术重点实验室, 合肥 230031

• 张礁石
• 1. 中国科学院安徽光学精密机械研究所环境光学与技术重点实验室, 合肥 230031;2. 安徽省环境光学监测技术重点实验室, 合肥 230031

• 桂华侨
• 1. 中国科学院安徽光学精密机械研究所环境光学与技术重点实验室, 合肥 230031;2. 安徽省环境光学监测技术重点实验室, 合肥 230031

• 余同柱
• 1. 中国科学院安徽光学精密机械研究所环境光学与技术重点实验室, 合肥 230031;2. 安徽省环境光学监测技术重点实验室, 合肥 230031

• 王杰
• 1. 中国科学院安徽光学精密机械研究所环境光学与技术重点实验室, 合肥 230031;2. 安徽省环境光学监测技术重点实验室, 合肥 230031

• 摘要：为分析2014年APE（Asia-Pacific Economic Cooperation）会议前后北京郊区大气颗粒物数浓度和质量浓度的变化特征及其主要影响因素，于当年11月在北京怀柔区中国科学院大学雁栖湖校区教学一楼楼顶利用微量振荡天平（TEOM）、扫描电迁移率颗粒物粒径谱仪（SMPS）和空气动力学粒径谱仪（APS）对大气颗粒物质量浓度和数浓度分布进行连续在线监测；同时结合地面气象参数和HYSPLIT轨迹模式，对颗粒物的来源和传输过程进行聚类、潜在源区贡献因子（PSCF）和浓度权重轨迹（CWT）分析.结果表明，APEC期间（11月5-11日）超细粒子（PM_0.01~1）数浓度、细粒子（PM_0.5~2.5）数浓度和粗粒子（PM_2.5~10）数浓度分别为（17720.1±998.7）、（30.9±3.34）和（0.12±0.01）cm^-3，比非APEC期间（即11月1-4日和11月12-30日）分别降低了28.8%、58.6%和64.7%；APEC期间ρ（PM_2.5）为（36.1±2.4）μg·m^-3，比非APEC期间降低55.5%.PM_0.5~2.5数浓度和PM_2.5~10数浓度降幅远大于PM_0.01~1数浓度，这表明APEC期间的减排措施对于PM_0.5~2.5和PM_2.5~10的控制效果优于PM_0.01~1，说明APEC期间对PM_0.5~2.5、PM_2.5~10数浓度进行了更有效的控制.对北京气流后向轨迹聚类分析发现，来自蒙古国、内蒙古、河北西北部、河北南部方向的气流轨迹对应北京郊区的PM_0.01~1数浓度最高，为30593 cm^-3，来自河北西北部、北京、天津、河北南部方向的气流轨迹对应北京郊区的PM_0.5~2.5、PM_2.5~10的数浓度及ρ（PM_2.5）均为最高，分别为190 cm^-3、0.65 cm^-3、168 μg·m^-3.综合潜在源区贡献因子分析法（PSCF）和浓度权重轨迹分析（CWT）的结果分析发现，观测期间北京PM_0.01~1与PM_0.5~2.5、PM_2.5~10的潜在源区存在明显的区别，其中PM_0.01~1数浓度的潜在源区分布区域相对较广，主要分布在内蒙古中部、河北西北部、河北中南部和山西东北部等地区，而PM_0.5~2.5和PM_2.5~10数浓度的潜在源区分布基本一致，而且区域相对较集中，主要分布在河北北部、山西东北部和河北中南部等地区.APEC期间与非APEC期间ρ（PM_2.5）的源区贡献因子分析和浓度权重轨迹分析表明，APEC期间ρ（PM_2.5）的主要源区分布比非APEC期间相对较集中，主要位于北京当地、天津等附近地区，该地区对观测点ρ（PM_2.5）的贡献值在24~40 μg·m^-3之间.

• Abstract：To study the variant characteristics of particle number and mass concentration before, during and after 2014 APEC period in Beijing subran, a synergy of TEOM, APS and SMPS, were conducted for the on-line measurements of particle number and mass concentration in the Yanqi northeastern Beijing from November 1th to November 30th in 2014. Sources and transportation of atmospheric particles during the experiment were discussed based on PSCF, CWT, surface meteorology data and backward trajectories from HYSPLIT model. The results showed that the average number concentrations of PM_0.01~1,PM_0.5~2.5 and PM_2.5~10 were (17720.1±998.7)、(30.9±3.34) and (0.12±0.01) cm^-3,respectively, during APEC period(5-11 Nov.), lower than the ones during non-APEC period, namely 28.8%、58.6% and 64.7% (1-4 Nov. and 12-30 Nov.). In APEC period the mass concentration of PM_2.5 was (36.1±2.4) μg·m^-3, which was 55.5% lower than non-APEC period. In addition the decreased level of number concentration variation of the PM_0.01~1 was less than that of PM_0.5~2.5 and PM_2.5~10, and it suggests that the control effect had more noticeable impact on the number concentration of PM_0.5~2.5 and PM_2.5~10 than PM_0.01~1 during APEC period. The results of the back-trajectory analysis showed that the average number concentration of ultrafine particles was 30593 cm^-3 when the back-trajectory come from Mongolia, the central of Inner Mongolia, northwest Hebei, Beijing and southern Hebei. Moreover, the average number concentration of fine particles, coarse particles and the mass concentration of PM_2.5 were 190 cm^-3, 0.65 cm^-3 and 168 μg·m^-3 with the back-trajectory of air coming from northwest Hebei, Beijing, Tianjin, southern Hebei. The results of PSCF and CWT showed that the potential sources of PM_0.01~1 and PM_0.5~2.5, PM_2.5~10 were very different in the observation period. The potential sources of ultrafine particle number concentration in Beijing region were mainly distributed in the central part of Inner Mongolia, northwest Hebei, Hebei and northeast Shanxi, while the potential source area of coarse particles and fine particles were more concentrated from northern Hebei, northeast Shanxi, Hebei and other regions in South Central China. Finally the PSCF and CWT analysis of the PM_2.5 mass concentration during the APEC and non-APEC demonstrates that the source area of PM_2.5 during the APEC period was relatively concentrated in Beijing, Tianjin and its adjacent areas with the contributing value ranged from 24 μg·m^-3 to 40 μg·m^-3.

• Key words：atmospheric particulate matter  PM_2.5  meteorological parameters  backward trajectories  clustering analysis  PSCF  CWT

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