丽江市冬季大气总悬浮颗粒物(TSP)中水溶性离子化学特征

Chemical Characteristic of Water-Soluble Ions in Total Suspended Particles (TSP) at Lijiang Winter Time

2008年12月～2009年1月在丽江市共采集25个TSP样品,目的是研究丽江市冬季TSP中水溶性离子的化学特征及它们的来源情况.结果表明,样品中主要水溶性离子的电荷浓度:Cl-、NO 3-、SO42-、Na+、NH 4+、K+、Mg2+、Ca2+分别为16.00、14.95、49.40、3.12、44.75、8.65、29.50、183.02 neq.m-3,样品中平均离子总电荷浓度值为349.39 neq.m-3,其中Ca2+平均浓度占平均离子总浓度的52.38%,阳离子平均浓度为阴离子平均浓度3.35倍.样品中SO24-/NO 3-均值为3.98,表明人类活动中固定源对大气环境影响程度大于移动源.通过计算相关系数和主因子分析,发现Ca2+和Mg2+主要来自于地表粉尘源,而NO 3-、SO42-、NH 4+和K+离子主要和丽江市冬季各种人类活动的燃烧过程有关,其中地表粉尘源影响相对较大,说明丽江市冬季大气TSP主要受自然环境因素影响.综上判断,丽江冬季大气TSP中各离子主要以CaCO3、(NH4)2SO4、MgCO3和KNO3的形式结合,并有少量的CaSO4和Ca(NO3)2存在.

25 total suspended particles（TSP） samples were collected at Lijiang city from Dec 2008 to Jan 2009.Analyzed results indicated that the concentration of Cl-,NO 3-,SO42-,Na ＋,NH 4＋,K ＋,Mg2 ＋ and Ca2 ＋ were 16.00,14.95,49.40,3.12,44.75,8.65,29.50 and 183.02 neq.m-3 respectively.The average total aerosol loading was 349.39 neq.m-3,and the average concentration of Ca2 ＋ was 52.38% percent of average total concentration,indicated it was the dominant ion in this sampling.The average concentration of detected cations was 3.35 times of anions,suggested the sum of cations generally exceed the sum of anions in our samples,and the main anion was not detected.The average value of SO42-/NO 3-was 3.98,showing that the sustained sources have mainly influences on air.According to the correlation coefficients among ions and factor analysis,Ca2 ＋ and Mg2 ＋ in our samples were from dust,and the sources of NO 3-,SO24-,NH 4＋ and K ＋ were related to various combustion processes by human activities.As a whole,the ions in our samples were mainly combined as CaCO3,（NH4）2 SO4,MgCO3,KNO3 and a little CaSO4 and Ca（NO3）2.