• 关键词：PM_2.5  水溶性离子  源解析  秸秆燃烧  珠海

• 基金项目：广东省科技计划项目（科技创新平台类） （No.2019B121201002）； 国家自然科学基金（No. 42105097）；中山大学中央高校基本科研业务费专项资金（No. 22qntd1908）

• 刘一鸣
• 中山大学大气科学学院， 广东省气候变化与自然灾害重点实验室， 珠海 519082;南方海洋科学与工程广东省实验室（珠海）， 珠海 519082;环珠江口气候环境与空气质量变化野外科学观测研究站， 广州 510275

• 郑浩阳
• 珠海市气象局， 珠海 519000

• 陈阁香
• 广东江扬环保咨询服务有限公司， 广州 510665

• 滕超
• 珠海市气象局， 珠海 519000

• 林泽健
• 生态环境部华南环境科学研究所， 广州 510655

• 摘要：2018年6月7日—7月10日，利用在线气体和气溶胶成分监测仪（IGAC）在珠海市沿海站对PM_2.5中水溶性离子浓度和气体开展连续观测分析.结果发现，夏初沿海地区水溶性离子处于较低水平，SO₄^2-、NH₄⁺、NO₃^-、Cl^-、Na⁺、Ca²⁺、K⁺、Mg²⁺浓度分别为4.78、1.87、1.16、0.92、0.37、0.27、0.11和0.11 μg?m^-3，其中，代表海洋来源的Na⁺和Cl^-浓度与珠江口东海岸的深圳沿海地区相当. Na⁺和Cl^-呈明显的白天高、夜晚低的日变化 特征，与海盐排放在海陆风环流下的输送有关.基于天气形势分析、气团来源分析和PMF来源解析方法研究了观测期间发生的两次污染过程，一次是受到强热带风暴外围下沉气流影响，一次是受到低压槽系统影响，在两次污染期间珠海沿海站受到偏北气流影响，初夏秸秆燃烧排放的污染物对沿海地区造成重要影响，K⁺和HONO浓度明显增加，大气氧化性的增加促进了夜间二次颗粒物和白天臭氧的生成，造成大气复合污染.在清洁阶段，珠海沿海地区受偏南气流影响，污染物浓度处于较低水平，海盐影响较大.

• Abstract：From June 7^th to July 10^th， 2018， the online gas and aerosol composition monitor （IGAC） was used to continuously observe and analyze the concentrations of water-soluble ions in PM_2.5 and gases at a coastal station of Zhuhai City. The water-soluble ions in the coastal areas in early summer were at a low level， and the concentrations of SO₄^2-， NH₄⁺， NO₃^-， Cl^-， Na⁺， Ca²⁺， K⁺， and Mg²⁺ were 4.78， 1.87， 1.16， 0.92， 0.37， 0.27， 0.11， and 0.11 μg?m^-3， respectively， in which the Na⁺ and Cl^- concentrations representing marine sources were comparable to those in the coastal area of Shenzhen on the east coast of the Pearl River Estuary. Concentrations of Na⁺ and Cl^- showed obvious diurnal variation characteristics （high during the day and low at night）， which were related to the transport of sea spray aerosol under the sea-land breeze circulation. Based on weather situation analysis， air mass source analysis and PMF source analysis methods， two pollution episodes occurred during the observation period were studied. One was under the control of the downdraft outside the strong tropical storm， and the other was affected by a low-pressure trough system. During these two episodes， the coastal site was affected by the northerly airflow， and the pollutants emitted from straw burning in early summer had an important impact on these areas. The concentrations of K⁺ and HONO increased significantly， and the increase in atmospheric oxidation capacity promoted the formation of secondary aerosols at night and ozone during the day， resulting in atmospheric compound pollution. During the clean days， the coastal areas of Zhuhai were affected by the southerly air flow， the pollutant concentration was at a low level， and the sea salt had a greater impact.

• Key words：PM_2.5  water-soluble ions  source apportionment  biomass burning  Zhuhai

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