春季黄渤海大气气溶胶的离子特征与来源分析

Characteristics and source analysis of atmospheric aerosol ions over the Yellow Sea and the Bohai Sea in spring

于2010年春季在黄海、渤海海域采集大气气溶胶总悬浮颗粒物(TSP)样品,并运用离子色谱法对其中主要的水溶性阴离子(Cl-、NO3-、SO24-、CH3SO3-(MSA))和阳离子(Na+、K+、NH4+、Mg2+、Ca2+)浓度进行了测定.分析结果显示,黄海、渤海气溶胶样品中主要水溶性离子总浓度分别为10.2～47.1μg·m-3和43.3～73.3μg·m-3,平均值分别为(25.5±6.6)μg·m-3和(59.9±14.4)μg·m-3,其中,二次离子(非海盐硫酸盐nss-SO24-、NO3-、NH4+)浓度最高,分别占黄海、渤海气溶胶测定离子总浓度的71.8%和80.5%.阴阳离子浓度平衡计算结果显示,气溶胶中酸碱组分中和不完全,呈现酸性.春季黄海、渤海气溶胶中MSA浓度平均值分别为(0.052±0.032)μg·m-3和(0.077±0.026)μg·m-3,渤海明显高于黄海.来源分析结果表明,黄海、渤海海盐硫酸盐对总SO24-的贡献率分别为5.1%和2.0%,而生源硫化物释放对nss-SO42-的贡献率分别为11.0%和7.4%,显示来自人为活动的输入仍是大气气溶胶中SO24-的最主要来源.另外,研究海域大气气溶胶中的nss-SO24-/NO3-比值为1.52,呈现下降趋势,表明近年来我国燃煤SO2的释放得到有效控制,而机动车辆尾气排放明显上升.

Samples of total suspended particulates （TSP） were collected over the Yellow Sea （YS） and the Bohai Sea （BS） in spring,2010.Main water-soluble anions （Cl-,NO-3,SO2-4 and CH3SO-3） and cations （Na＋,K＋,NH＋4,Mg2＋ and Ca2＋） in these samples were analyzed by ion chromatography.The concentrations of the total water-soluble ions ranged from 10.2 to 47.1 μg·m-3 over the YS and from 43.3 to 73.3 μg·m-3 over the BS,respectively,with the average values of （25.5±6.6） μg·m-3 and （59.9±14.4） μg·m-3.The analytical results indicated that the concentrations of secondary ions （nss-SO2-4,NO-3,NH＋4） in aerosols were the highest,accounting for 71.8% and 80.5% of the total identified ions over the YS and the BS,respectively.The calculated results of equivalent concentrations of anions and cations showed that acid and alkaline compositions were not neutralized completely with weak acidity.The average concentrations of MSA were（0.052±0.032）μg·m-3 and （0.077±0.026）μg·m-3 in the aerosol samples collected over the YS and the BS,respectively.According to the analysis of sulfate source,sea-salt sulfates accounted for 5.1% and 2.0% of the total sulfates over the YS and the BS,respectively,and the contributions of biogenic sulfates to nss-SO2-4 were 11.0% and 7.4%,showing that human activities were the main source of sulfate in aerosols over the study areas.Furthermore,the ratio of nss-SO2-4-to-NO-3 in aerosols was 1.52,showing that the emission of SO2 from coal burning had been controlled effectively,while the emission from automobile exhaust had increased obviously.