• 关键词：细颗粒物(PM_2.5)  长期观测  颗粒物组成  重污染  成都

• 基金项目：环境保护部公益项目(No.201009001);首都经济贸易大学青年教师科研启动基金(No.00891554410201);2015年首都经济贸易大学中青年教师科研提升基金

• 陈源
• 1. 北京大学环境科学与工程学院, 北京 100871;2. 首都经济贸易大学安全与环境工程学院, 北京 100070

• 谢绍东
• 北京大学环境科学与工程学院, 北京 100871

• 罗彬
• 四川省环境监测中心, 成都 610041

• 摘要：为了解成都市大气细颗粒物的污染特征,于2012年5月-2013年5月在成都市城区开展了每6 d采集1次样品的长期颗粒物观测.利用十万分之一分析天平、热光碳分析仪、离子色谱、电感耦合等离子体质谱(ICP-MS)分别分析了颗粒物样品的质量浓度、有机碳/元素碳、水溶性离子、无机元素等,同步收集了污染物在线观测数据、气象数据和卫星遥感数据.结果表明,采样期间,成都市可吸入颗粒物(PM₁₀)和细粒子(PM_2.5)浓度颗粒物浓度分别高达(129.7±76.4)和(91.6±54.3) μg·m^-3,PM_2.5中以二次无机离子(SNA,43.6%)和有机物(OM,31.2%)污染最为突出,其次为土壤组分(Soil,13.8%)、元素碳(EC,5.0%)和微量元素(Trace,0.8%);1月、3月、5月和10月是污染较重的月份.通过比较揭示了不同污染源影响下的典型污染特征.生物质燃烧期间,成都城区PM_2.5浓度达214.3 μg·m^-3,PM_2.5/PM₁₀比达0.89,其中OM贡献增加至57.2%,K⁺浓度达8.7 μg·m^-3,OC/EC比达8.3,SNA比重下降;而沙尘传输期间,PM_2.5浓度为122.6 μg·m^-3,仅占PM₁₀浓度的0.28,PM_2.5中土壤组分比例剧增至77.3%,SNA和无机元素的比重明显下降;静稳天气下PM_2.5浓度为261.0 μg·m^-3,各组分比重并无明显变化,硝酸盐和铵盐比例稍有增加.

• Abstract：Particulate samples were collected at an urban sampling site in Chengdu every six days from May 2012 to May 2013 to investigate the chemical characteristics and pollution pattern of fine particles. Using electronic balance, thermal/optical carbon analyzer, ion chromatography and Inductively Coupled Plasma Mass Spectrometry (ICP-MS), mass concentrations, OC (organic carbon)/EC (elemental carbon), water-soluble ions and inorganic elements of particulate matter (PM) were analyzed. On-line measurement data of gaseous pollutants, meteorological data, and remote-sensing data were collected simultaneously during the sampling period. During the sampling period, the annual mean PM₁₀ and PM_2.5 concentrations were (129.7±76.4) and (91.6±54.3) μg·m^-3, respectively. Secondary inorganic aerosols (SNA, 43.6%) and organic matter (OM, 31.2%) were the most abundant components in PM_2.5, followed by soil (13.8%), EC (5.0%), and trace elements (0.8%). Weak seasonal variations of PM_2.5 were observed at the urban sampling site, while PM_2.5 levels in January, March, April, and October were relatively higher than those in other months. Under the influence of biomass burning, PM_2.5 in urban Chengdu increased substantially to 214.3 μg·m^-3 and OC/EC ratios rose to 8.3 with OM contribution of 57.2%. Surprisingly, K⁺ concentrations increased to 8.7 μg·m^-3, while SNA concentrations decreased. During dust transport episode in Chengdu, soil contributed 77.3% of the PM_2.5 concentration (122.6 μg·m^-3), and PM_2.5 accounted for 28% of PM₁₀ mass. PM_2.5 concentrations during heavy pollution caused by stable weather increased to 261.0 μg·m^-3, but the composition patterns of PM_2.5 were rather constant with minor increases in nitrate and ammonia.

• Key words：fine particle (PM_2.5)  long-term observation  composition  heavy pollution  Chengdu

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