【作者】 王丽；

【导师】 徐仲均；

【作者基本信息】 北京化工大学 ， 环境科学与工程， 2013， 硕士

【摘要】 由于大气颗粒物对气候、环境和人体健康影响很大,而水溶性无机离子又是其中的重要化学组成,研究不同粒径水溶性无机离子的浓度以及其来源对于大气气溶胶的发展有极其深远的意义。京津冀近年来,随着能源的消耗不断攀升,机动车尾气的大量排放,区域污染越来越显著,尤其是灰霾天气的频繁出现,对于京津冀大气气溶胶的重要化学组成-水溶性无机离子的研究也迫在眉睫。本文于2010年8月-2011年8月利用Andersen分级采样器采集了北京、天津、唐山和保定大气颗粒物样品,采用离子色谱分析其中的离子成分,进一步阐述了京津冀水溶性无机离子的浓度水平、粒径分布和来源,并提出了控制防治措施。结果表明：京津冀四个站点总悬浮颗粒物(TSP)中总水溶性无机离子浓度(p(TWSI))天津>保定>北京>唐山,细粒子中p(TWSI)保定>天津>北京>唐山。北京大气粗、细粒子中总水溶性无机离子(TWSI)平均浓度分别为41.36±15.76gg·m-3和66.54±47.95μg·m3；天津大气粗、细粒子中TWSI平均浓度分别为48.04±15.79μg·m3和69.12±34.85μg·m-3；唐山大气粗、细粒子中TWSI平均浓度分别为39.40±11.03μg-m-3和61.80±44.63μg·m-3；保定大气粗、细粒子中TWSI平均浓度分别为40.49±13.32μg·m-3和71.73±45.12μg·m-3；四个站点仅细粒子中的TWSI就都超出了环境质量标准中PM2.5年均浓度限值(35gg·m3),说明京津冀地区水溶性无机离子污染严重。京津冀四个站点大气细粒子中主要的水溶性无机离子均为NO3-、SO42-、NH4+和Cl-；粗粒子中主要的水溶性无机离子均为NO3-、Ca2+和SO42-。基本所有水溶性无机离子的季节变化均为夏季或冬季最高。粒径分布分析结果表明,ρ(SO42-)、ρ(NO3-)、ρ(Na+)、ρ(Cl-)和ρ(K+)均呈双峰分布,在0.43-1.1μm出现第一峰值,在4.7～5.8μm出现第二峰值；ρ(NH4+)呈细模态单峰分布,在0.43～1.1μm出现峰值；ρ(Mg2+)和ρ(Ca2+)呈粗模态单峰分布,在4.7～5.8μm出现峰值。京津冀四个站点SNA除了北京没有发生模态转移外,都有模态转移的明显迹象,湿度可能是发生这种转移的主要影响因素。京津冀雾霾天气水溶性无机离子浓度的增加主要来自于细粒径段二次离子的积累,其它离子对其影响较小。京津冀四个典型城市水溶性无机离子的来源主要是二次源、扬尘、生物质燃烧、NH4+和N03-在粗粒径段的非均相反应、海盐等。细粒子中水溶性无机离子的来源主要是二次源和扬尘,而且四个站点二次源的方差贡献率都超过40%,说明京津冀燃煤和机动车尾气污染严重,整个区域应加强对气态污染物人为排放的控制。更多还原

【Abstract】 Aerosol has important effects on climate, environment and human health and water-soluble ions are important chemical composition in aerosol. It is important to study concentration levels, sources and size distributions of water-soluble ions in aerosol. In recent years, with the increasing of energy consumption and the amount of automobile, regional pollution has become more serious in Beijing-Tianjin-Hebei Region. Especially since the haze happened frequently in Beijing-Tianjin-Hebei Region, it is an imminent study about water-soluble ions in aerosol.To investigate the concentration levels, sources and size distributions of water soluble inorganic ions (WSI), size-segregated aerosol samples were collected using Andersen cascade sampler from Aug2010to Aug2011in Beijing, Tianjin, Tangshan and Baoding. The WSI were analyzed by ion chromatography(IC).The results indicated that the order of total WSI (TWSI) concentration of TSP in the region was Tianjin>Baoding>Beijing>Tangshan. The order of TWSI of the fine particles in the region was Baoding>Tianjin>Beijing>Tangshan. The annual mean concentrations of TWSI in the coarse mode were41.36±15.76,48.04±15.79,39.40±11.03,40.49±13.32μg·m-3in Beijing, Tianjin, Tangshan and Baoding, respectively. The annual mean concentrations of TWSI in the fine mode were66.54±47.95,69.12±34.85, 61.80±44.63,71.73±45.12μg·m-3in Beijing, Tianjin, Tangshan and Baoding, respectively. All the annual mean concentrations of TWSIin the fine mode in the four sites had exceeded averaged concentration of PM2.5in the environmental quality standards (35μg·m-3), which indicated that the pollution of TWSI was serious. Secondary water-soluble ions (SWSI)(SO42-, NO3-and NH4+) and Cl-were the main components, and were mainly found in the fine particles in the four sites of Beijing-Tianjin-Hebei Region. In the coarse particles, NO3-、Ca2+and SO42-were the dominant contributions to WSI. Almost all water-soluble ions in fine particles are similar seasonal variation characteristics.The highest WSI concentrations appeared in winter or in summer.Particle size distribution analysis reveals that SO42-、NO3-、Na+and K+showed a bimodal size distribution. The first peak with fine mode appeared at0.43～.1μm, and the second peak with the coarse mode appeared at4.7～5.8μm. NH4+was unimodal the peak with the fine mode of0.43～1.1μm. Ca2+and Mg2+were unimodal the peak respectively with the coarse mode of4.7～5.8μm. Modes of SNA transferred obviously in Beijing-Tianjin-Hebei Region, except Beijing, which may be due to higher humidity. Haze is more conducive to generation and accumulation of water-soluble ions, in which the accumulation of SNA is major.Sources analysis indicated that dust, biomass burning emission, sea salt, secondary formation in fine particles and heterogeneous reaction of NH4+and NO3-in coarse particles were the major sources of TWSI in Beijing-Tianjin-Hebei Region. Secondary formation and dust were the major sources of the fine particles, in which the contributing rate of secondary formation was over40%. Coal burning emission and exhaust pollution in Beijing-Tianjin-Hebei Region becomes more and more serious. The whole area should strengthen the control of gaseous pollutants emissions.更多还原