北京市区冬季PM_(2.5)污染特征及来源分析

Pollution Characteristics and Source Analysis of PM_(2.5) in Winter in Beijing Urban Area

选取北京市区为采样点,于2016年1月进行PM_(2.5)采集,并分析了PM_(2.5)和水溶性组分的污染特征和来源。结果表明,采样期间北京市PM_(2.5)质量浓度平均为67.7μg/m^3,水溶性离子是PM_(2.5)的主要组分,其中SO_4^(2-)、NO_3^-和NH_4^+之和占总离子的79.1%;Ca^(2+)和Mg^(2+)分别占PM_(2.5)质量浓度的2.5%和0.9%,海盐气溶胶和K^+分别占PM_(2.5)的3.6%和1.6%。采样期间NO_3^-/SO_4^(2-)为1.1,表明NO_2和SO_2主要来自移动源的贡献。北京市区冬季PM_(2.5)主要来自二次污染源、扬尘、生物质燃烧和海盐气溶胶,贡献率分别为42.351%、21.164%、16.314%和5.436%。

Beijing urban area was selected to collect PM2.5 samples in January 2016. Pollution characteristics and source of PM2.5 and water soluble ions were analyzed. Results demonstrated that the mass concentrations of PM2.5 in Beijing was 67.7 pg/m3 during sampling period. Water soluble ions were the main components of PM2.5. The sum concentration of SO42-, NO3-, and NH4＋ accounted for 79.1% of water soluble ions. The concentrations of Ca2＋ and Mg2＋ accounted for 2.5% and 0.9% of PM2.5 , respectively. Sea-salt aerosols and K＋ accounted for 3.6% and 1.6%, respectively. The ratio of NO3- and SO42- concentrations was 1.1 during sampling period, which indicated that the NO2 and SO2 were mainly derived from mobile sources. PM2.5 was mainly derived from secondary pollution, dust, biomass burning and sea salt aerosols, and the contribution rates were 42.351%,21.164%, 16.314%, and 5.436%, respectively during winter in Beijing urban area.