• 关键词：PM_2.5  重污染  碳组分  水溶性离子  源解析  气象因子  轨迹传输

• 基金项目：国家重点研发计划子课题（No.2017YFC0212405）

• 王维思
• 河南省环境监测中心, 河南省环境监测技术重点实验室, 郑州 450000

• 王楠
• 河南省环境监测中心, 河南省环境监测技术重点实验室, 郑州 450000

• 高玉娟
• 南京雨后地软环境技术有限公司, 南京 210013

• 左瑞亭
• 1. 南京雨后地软环境技术有限公司, 南京 210013;2. 江苏及象生态环境研究院有限公司, 南京 210013

• 马双良
• 河南省环境监测中心, 河南省环境监测技术重点实验室, 郑州 450000

• 王晶晶
• 河南省环境监测中心, 河南省环境监测技术重点实验室, 郑州 450000

• 摘要：为研究郑州冬、春季重度污染期间细颗粒物的组分特征、污染来源、气象影响因素及外来传输影响，基于本地超级站污染监测数据及相关气象要素监测数据对重污染时段进行分析，并对本地污染成因进行探讨.结果表明，2019年1—3月郑州共有426 h达到重度及以上污染水平，首要污染物均为PM_2.5.重污染时段碳组分（OC+EC）共占PM_2.5的14.6%，OC与EC存在显著相关性，1、2、3月的r值分别为0.72、0.89和0.91，且二者比值多介于2~4之间，表明机动车和燃煤排放是碳组分的主要来源；水溶性离子浓度排序为NO₃^- > NH₄⁺ > SO₄^2- > Cl^- > K⁺ > Ca²⁺ > Mg²⁺ > Na⁺，SNA（SO₄^2-、NO₃^-、NH₄⁺）浓度达123.37 μg·m^-3，占PM_2.5的61.2%，且NO₃^-占比达30.2%， NO₃^-/SO₄^2-值为1.98，说明移动源对水溶性组分的贡献大于固定源. PMF受体解析结果按污染源贡献量大小依次为：机动车源（34.9%）、二次源（24.6%）、燃煤源（20.2%）、扬尘源（9.2%）、生物质及烟花爆竹源（8.2%）和工业源（2.9%），机动车和燃煤燃烧是造成大气重污染的主要排放源.气象分析表明，与清洁时段相比，重污染期间大气整体处于有利于颗粒物二次生成和不利于污染扩散的条件下，整体温度偏低（3.2 ℃），相对湿度较高（67%），风速较弱（1.3 m·s^-1）.除本地污染物的累积外，来自偏东和偏南方向的短距离传输及东北方向中长距离输送（分别占外界传输的36.4%、22.6%和22.0%）也是造成郑州重污染天气的重要原因.

• Abstract：Based on the supersite monitoring data and the corresponding meteorological data, the pollution mechanism for winter and spring in Zhengzhou are investigated, and the compositional characteristics, source apportion, meteorological effects and the transportation contributions to the particles during the heavy polluted periods are revealed. From January to March 2019, the total heavy polluted period reaches 426 hours with the major pollutant PM_2.5. The amounts of OC and EC account for 14.6% to PM_2.5, with the correlation of r being 0.72、0.89 and 0.91 during the three months respectively. The ratio of OC to EC is 2~4 mostly, which implies that the emissions from vehicle and coal combustion are probably the major sources for carbon component. The order of mass concentrations of water-soluble ion gives NO₃^- > NH₄⁺ > SO₄^2- > Cl^- > K⁺ > Ca²⁺ > Mg²⁺ > Na⁺. SNA accounts for 61.2% to PM_2.5 with the concentration 123.37 μg·m^-3, while NO₃^- accounts for 30.2% with the NO₃^-/SO₄^2- ratio 1.98, which indicates the larger contribution from mobile sources than stationary sources. PMF results present the contribution order of pollution sources to be vehicle source (34.9%), secondary source (24.6%), coal source (20.2%), dust source (9.2%), biomass and fireworks source (8.2%) and industry source (2.9%), i.e, vehicle and coal source are the primary pollution sources. The typical meteorological condition in heavy polluted periods, e.g., the low temperature (3.2℃), high humidity (67%) and week wind (1.3 m·s^-1), are in favor of the hygroscopic growth and secondary transformation of particles. Besides the local accumulation, backward trajectory shows the important contribution of transportation of pollutants, including the short-distances transportation from east and south and the middle-long distance transportation from northeast with their contribution ratios 36.4%, 22.6% and 22.0% respectively.

• Key words：PM_2.5  heavy pollution  carbon component  water-soluble ions  source identification  meteorological factors  trajectory transmission

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