河北省涞水县大气颗粒物单颗粒分析表征及来源识别

为了解河北省涞水县颗粒物污染特征，采用单颗粒分析技术扫描电镜-X射线能谱法和气团后向轨迹分析技术对该县2015年3个典型污染时段〔即正常管控、严格管控（2015年阅兵期间）及发生严重颗粒物染污〕采集的7个大气颗粒物样品进行了分析表征和来源解析.共测量了1 506个粒径≥0.5 μm的单颗粒，其中粒径小于2.5 μm的颗粒占98%以上，测量结果揭示了细颗粒污染特征.结果表明:①碳质颗粒为主要颗粒物种类，其检出数目占比在90%以上.②非供暖期严格管控时段，当地居民日常生活产生的球形碳质颗粒检出数目占比最高.③非供暖期正常管控时段，机动车排放的碳质集合体颗粒检出数目占比最高，交通污染贡献最大.④供暖期球形碳质颗粒检出数目占比最高，含硫颗粒检出数目占比相对增加，燃煤的贡献最大.3个采样时段48 h气团后向轨迹分析结果表明，在空气质量良好、颗粒物污染水平较低的情况下，影响研究区域空气质量的主要是本地源；雾霾天气（处于严重颗粒物污染时段）时，西南方向外来源和本地源共同构成研究区域的颗粒物污染状态. 

Individual-Particle Analysis and Sources Identification of Atmospheric Fine Particles in Laishui County, Hebei Province of China

Laishui County in Hebei Province is located 90 km southwest to Beijing. In order to understand the local pollution characteristics of particulate matter, individual-particle analysis technique (SEM-EDX) was performed on 7 samples of atmospheric particles collected in 3 typical periods of atmosphere pollution in Laishui County. In total 1506 particles (diameter larger than 0.5 μm) were measured, and the diameter of more than 98% particles was less than 2.5 μm, indicating a characteristic of severe fine particle pollution. The results show that:(1) Carbonaceous particles are the main types of particulate matter and the number detected is over 90%. (2) During the China Military Parade, a non-heating period with strict atmospheric control policies implemented, the spherical carbon-rich particles, which were mainly from daily activities of citizens, had the highest number abundance among all particles. (3) During normal non-heating days, abundance of vehicle-emitted soot aggregates was the highest, which showed the largest contribution of traffic to particle pollution. (4) Abundance of spherical carbon-rich particles was highest during heat-period, while the abundance of S-rich particles was significantly increased, implying the main contribution of coal combustion emission to air pollution. Combined with 48-h analysis of air mass back trajectories in 3 typical periods of atmosphere pollution, it was concluded that the local sources were the main cause of pollutants during periods with low level air pollution, while external and local sources both play an important role during periods with severe air pollution in Laishui County.