中国科学院海岸带环境过程与生态修复重点实验室知识库

中国科学院烟台海岸带研究所; 中国科学院大学; 中国科学院广州地球化学研究所

首次在位于渤海海峡中部的砣矶岛国家大气背景监测站连续采集大流量 PM_(2.5)样品，对2011年12月至2012年12月期间的65个样品进行了分析，包括质量浓度、有机碳、元素碳、水溶性离子、无机元素等。结果表明，砣矶岛PM_(2.5)的年均质量浓度为54.6μg/m~3(17.3~143.8μg/m~3)，超过国家空气质量标准(35μg/m~3)。在季节变化上表现为春季与夏季高(平均浓度分别为73.6μg/m~3与60.7μg/m~3)，分别受沙尘和山东半岛生物质燃烧的影响，而冬季最低(39.0μg/m~3)，与渤海地区冬季频降暴雪有关。PM_(2.5)中SO_4~(2-)、OM、NO_3~-、MMO是最主要的成分，分别占PM_(2.5)质量的18.8%、16.5%、10.8%和9.4%，其次为NH_4~+(3.5%)和EC (3.3%)。砣矶岛PM_(2.5)的组成较好地反映了颗粒物的主要来源及其季节变化特征，如：春季样品中Fe、Ca与Mg含量最高，与春季北方地区普遍受沙尘影响有关；夏季较高的K~+浓度与OC/EC比值反映夏季风影响下山东半岛生物质燃烧对砣矶岛PM_(2.5)的重要贡献；夏季SO_4~(2-)与NO_3~-的异常浓度反映了二次气溶胶形成的普遍特征。此外，较高的Na~+浓度与V/Ni比值表明海盐和船舶废气对砣矶岛PM_(2.5)有一定影响。

High-volume PM_(2.5) samples were collected consecutively at the national air background monitoring station at Tuoji Island, which is located in the middle of the Bohai strait. Sixty-five samples collected during December 2011 to December 2012 were analyzed to obtain PM_(2.5) concentrations and chemical compositions such as OC, EC, inorganic elements, and water-soluble ions. The average mass concentration of PM_(2.5) was 54.6mug/m~3 (17.3~143.8 mug/m~3), exceeding the standard value of 35 mug/m~3 of the National Ambient Air Quality Standard (NAAQS). High values of seasonal concentration occurred in spring and summer (73.6 mug/m~3 and 60.7 mug/m~3 in average, respectively), which were related with the dust storm in north China and biomass burning from Shandong peninsula, respectively. The lowest concentration appeared in winter (39.0mug/m~3) that may be affected by the wet deposition of clean mechanism frequent snowstorms. Sulfate (18.8%), organic matters (16.5%), nitrate (10.8%), and main metal oxides (9.4%) were the main components of PM_(2.5), followed by ammonium (3.5%) and EC (3.3%). The chemical compositions of PM_(2.5) reflected the main sources as well as their seasonal variations at Tuoji Island. For example, the high concentrations of Fe, Ca, and Mg in spring samples could be related with dust storms occurred frequently in north China, while the high values of K~+concentration and OC/EC ratio in summer reflected the series biomass combustion in Shandong peninsula. The extremely high concentrations of SO_4~(2-) and NO_4~- in summer reflected the formation of secondary aerosols. Additionally, high values of Na~+ concentration and V/Ni ratio in PM_(2.5) showed that sea salt and shipping emissions also had certain contribution to PM_(2.5) at Tuoji Island.