摘要
利用扫描电镜-x射线能谱仪（SEM-EDX）、离子色谱、电感耦合等离子发射光谱和全自动化学分析仪器对乌鲁木齐市采暖期大气细颗粒物PM2．5）的形态结构及水溶性无机离子特征进行分析。结果表明：①乌鲁木齐市不同功能区大气PM2．5，类型多样，主要类型有硅铝酸盐、硅铝飞灰、铁氧化物颗粒、硫酸／碳酸盐晶体、钛聚集颗粒物、碳质气溶胶（烟尘集合体、焦油球、不规则碳质颗粒）、富氟颗粒和不明物质等，其中硅铝酸盐、硅铝飞灰、烟尘集合体在各个功能区都观测到，富氟颗粒仅存在于头屯河区、天山区和水磨沟区；②SO4^2-、NH4^＋、NO3^-、C1^-为乌鲁木齐市水溶性无机离子的主要组成部分，占全部无机离子的90．3％；③乌鲁木齐市大气PM2.5的pH在3．72-5．76之间，平均值为5．11，其大气气溶胶整体偏酸性，其中[NO3^-]与[SO4^2-]的比值小于1，可认为固定源排放是乌鲁木齐市大气PM2．5中水溶性无机离子的主要来源。
PM2.5 aerosol samples of Urumqi,a typical city in arid area of Northwest China, were collected during the heating period of Nov. 2013 to Feb. 2014. Microscopic morphology and elemental composition of PMzs were measured using a Field Emission Scanning Electron Microscope with Energy-Dispersive Spectrometer （SEM-EDX）, water-soluble ions of PM2.5 were analyzed by using Ion Chromatography and Automated Discrete Analyzers simulta- neously. The results indicated that the particles of PMz 5 can be classified as following groups ： aluminosilicate/silica minerals, fly ash with rich Si-A1, Fe-oxide particles, sulfate/carbonate crystals, Ti-abundant particle, carbonaceous aerosols （ including soot, tar ball and irregularly shaped carbon）, F-rich particles and some particles which we did not know. Among them, aluminosilicate/silica minerals, Si-Al-rich fly ashes and soot were observed in all functional areas of this study. F-rich particles were only observed in Toutunhe district, Tianshan district, Shuimogou district. Water-soluble components including SO4^2- , NH4＋ , NO3 - , and CI were dominant in PMz5 of Urumqi, accounting for 90.3 % of total inorganic elements. The pH value of PM2.5 in Urumqi was 5.11 in average, varying from 3.72 to 5.76, that means the whole aerosol in Urumqi is 1. The emission of fixed sources was considered Urumqi. partially acid and the mass ratio of [ NO3^ - ]/ SO4^2- ] is less than to be the major source of water-soluble inorganic ions of PM2.5 in
出处
《干旱区研究》
CSCD
北大核心
2015年第3期543-550,共8页
Arid Zone Research
基金
中国科学院百人计划项目
