中国中东部地区典型城市大气细颗粒物中化学组成特征及来源解析研究

发布时间：2018-05-18 04:27

本文选题：中东部地区 + PM_(2.5)　；参考：《南京大学》2017年硕士论文

【摘要】：随着经济的快速发展和城市化的进程不断加快,我国中东部地区大气污染持续恶化,大气颗粒物尤其是大气细颗粒物PM2.5对空气质量、气候变化和人体健康造成严重的负面影响。本研究于2014年12月至2015年11月不同季节的代表性月份在我国中东部地区的5个典型城市,分别是北京、南京、武汉、太原和广州进行了大气PM2.5的离线连续观测,分析其质量浓度污染特征。本研究同时分析了大气PM2.5中水溶性无机离子、有机碳及元素碳的含量和时空变化特征,并利用主成分分析法对PM2.5中水溶性无机离子和碳组分进行了来源解析。本研究成果旨在为政府制定有效的污染防控策略提供科学理论依据。研究结果如下:根据我国最新《空气环境质量标准》二级标准(GB 3095-2012,75μg/m3),南京和太原PM2.5污染严重,其次为武汉和北京;广州污染最轻。5个城市全年PM2.5污染等级均以良和轻度污染天气为主,总的百分比为67.7%～81.1%。污染源、区域大气传输和气象条件共同作用,导致PM2.5具有明显的季节差异性。冬季和(或)秋季其PM2.5日均浓度变化波动范围较大,且冬季PM2.5平均浓度最高,而春季和夏季变化趋势较为平稳。水溶性无机离子是大气PM2.5的主要化学组分之一,总水溶性无机离子在PM2.5中所占百分比为38.5%(北京)、44.3%(南京)、49.0%(太原)、46.7%(武汉)、32.2%(广州)。其中SO42-N03-和NH4+(简称SNA)是主要的水溶性无机离子种类,占总水溶性无机离子的74.6%(北京)、82.%(南京)、73.9%(太原)、85.2%(武汉)、86.2%(广州)。SNA/PM2.5百分比的季节变化均表现为夏季和秋季较高,冬季和春季较低。北京和广州PM2.5呈电中性,南京和太原PM2.5呈碱性,武汉PM2.5呈酸性。太原PM2.5中NH4+含量足以完全中和SO42-、NO3-和Cl-,而其他4个城市PM2.5中NH4+相对较为缺乏,其中南京和武汉NH4+仅能部分中和SO42-。北京移动排放源对大气PM2.5污染的贡献占主导地位。南京固定排放源和移动排放源对pM2.5的贡献相当。武汉、太原和广州的固定排放源对其PM2.5的贡献占主导。碳组分也是大气PM2.5的主要成分之一,北京、太原、武汉和广州的碳质气溶m((TCA)年均浓度分别为24.73μg/m3、34.79μg/m3、26.17μg/m3和16.85μg/m3,分别占PM2.5质量浓度的34.4%、36.6%、30.3%和26.9%。PM2.5中有机碳(OC)年均浓度是元素碳(EC)的1.9～2.3倍。冬季PM2.5中OC和EC浓度最高,而夏季最低。北京、太原和武汉PM2.5中OC和EC具有相同的来源,而广州OC和EC来源较为复杂。4个城市大气PM2.5中OC/EC均大于2.0,表明均存在二次有机碳(SOC)污染。太原SOC年均浓度最高,为10.9μg/m3,在OC中所占百分比为69.0%;广州SOC浓度最低,为4.0μg/m3所占百分比54.0%。受排放源和气象条件影响,SOC浓度季节变化规律不同于SOC/OC占比变化规律。利用主成份分析(PCA)对中东部地区5个城市大气PM2.5中的水溶性无机离子和碳组分进行来源解析。结果表明:北京市PM2.5中水溶性无机离子主要来源于二次源、生物质燃烧和扬尘;碳组分主要来源于生物质燃烧、燃煤和机动车尾气。南京水溶性无机离子主要来源于燃煤、机动车尾气、生物质燃烧和扬尘。太原PM2.5中水溶性无机离子的主要来源是二次源、生物质燃烧、燃煤、扬尘和农业畜牧;碳组分的主要来源是生物质燃烧、燃煤、汽油车尾气。武汉水溶性无机离子主要来源于二次源、燃煤、生物质燃烧和扬尘;碳组分主要来源于燃煤、汽油车尾气和生物质燃烧。广州水溶性无机离子主要来源于二次源、生物质燃烧、扬尘和燃煤;碳组分主要来源于燃煤、机动车尾气、生物质燃烧。由此可以看出,以清洁能源替代燃煤,控制机动车保有量的增长并提高燃油质量,严禁秸秆等生物质燃烧,以及提高绿色植被覆盖率,应成为改善中东部地区大气环境质量的重要手段。
[Abstract]:With the rapid development of the economy and the accelerating process of urbanization, atmospheric pollution in the eastern and Middle Eastern regions of China has been deteriorating. The atmospheric particles, especially the fine particulate matter PM2.5, have caused serious negative effects on air quality, climate change and human health. The representative months of this study from December 2014 to November 2015 were in the representative months. 5 typical cities in the middle eastern part of China, Beijing, Nanjing, Wuhan, Taiyuan and Guangzhou, have carried out an off-line continuous observation of atmospheric PM2.5 to analyze the characteristics of its mass concentration pollution. This study also analyzed the content and spatio-temporal characteristics of water soluble inorganic ions, organic carbon and element carbon in atmospheric PM2.5, and used principal component analysis. The source analysis of water-soluble inorganic ions and carbon components in PM2.5 was carried out. The results of this study are aimed at providing scientific theoretical basis for the government to formulate effective pollution prevention and control strategies. The results are as follows: according to the latest "standard of air environmental quality" in China (GB 3095-2012,75 mu g /m3), the PM2.5 pollution in Nanjing and Taiyuan is serious, followed by Wuhan and Beijing; the most polluted.5 cities in Guangzhou are both good and mild pollution weather, the total percentage is 67.7% to 81.1%. pollution sources, the regional atmosphere transmission and meteorological conditions are combined, resulting in the obvious seasonal difference of PM2.5. The fluctuation range of the daily average concentration of PM2.5 in winter and (or) autumn is larger. And the average concentration of PM2.5 in winter is the highest, but the change trend in spring and summer is more stable. Water soluble inorganic ions are one of the main chemical components of atmospheric PM2.5. The percentage of the total water-soluble inorganic ions in PM2.5 is 38.5% (Beijing), 44.3% (Nanjing), 49% (Taiyuan), 46.7% (Wuhan), 32.2% (Guangzhou). Among them, SO42-N03- and NH4+ (abbreviated as SNA) are the main components of the water soluble inorganic ions. The main types of water-soluble inorganic ions, 74.6% (Beijing), 82% (Nanjing), 73.9% (Taiyuan), 85.2% (Wuhan), 86.2% (Guangzhou) and 86.2% (Guangzhou), are all in summer and autumn, and in winter and spring are lower. The PM2.5 of Beijing and Guangzhou is neutral, and Nanjing and Taiyuan PM2.5 are alkaline, Wuhan PM2.5 The content of NH4+ in Taiyuan PM2.5 is sufficient to completely neutralize SO42-, NO3- and Cl-, while NH4+ in the other 4 cities is relatively deficient in PM2.5, of which the contribution of Nanjing and Wuhan NH4+ only in partial neutralization and SO42-. Beijing emission sources to the atmospheric PM2.5 pollution is dominant. The contribution of the Nanjing fixed discharge source and the mobile emission source to pM2.5 is equal. The contribution of the fixed emission sources of Wuhan, Taiyuan and Guangzhou to its PM2.5 is dominant. The carbon component is one of the main components of the atmospheric PM2.5, and the annual concentration of carbon gas soluble m (TCA) in Beijing, Taiyuan, Wuhan and Guangzhou (TCA) is 24.73 u g/m3,34.79 mu g/m3 and 16.85 u g/m3, respectively, accounting for 34.4%, 36.6%, 30.3% and 26.9%.PM2. respectively of the mass concentration of PM2.5, respectively. The average annual concentration of organic carbon (OC) in 5 is 1.9 to 2.3 times the element carbon (EC). In winter, the concentration of OC and EC is the highest and the lowest in summer. Beijing, Taiyuan and Wuhan PM2.5 OC and EC have the same source, while Guangzhou OC and EC sources are more complex than 2 in.4 urban atmosphere PM2.5, indicating that there are two organic carbon pollution. Taiyuan pollution. The average annual concentration is 10.9 mu g/m3, the percentage in OC is 69%, the SOC concentration in Guangzhou is the lowest, and the percentage 54.0%. of 4 mu g/m3 is affected by the emission source and the meteorological condition. The seasonal variation of SOC concentration is different from the SOC/OC occupation ratio, and the principal component analysis (PCA) is used for the water solubility in the atmosphere PM2.5 in the Middle East region of 5 cities. The results show that the water-soluble inorganic ions in Beijing PM2.5 mainly come from the two source, biomass combustion and dust, and the main sources of carbon components are biomass combustion, coal and motor vehicle exhaust. The main sources of water soluble inorganic ions in Nanjing are from coal, vehicle exhaust, biomass combustion and dust. The main sources of water-soluble inorganic ions in the original PM2.5 are two sources, biomass combustion, coal combustion, dust and agricultural animal husbandry. The main sources of the carbon components are biomass combustion, coal combustion, and gasoline vehicle exhaust. The main sources of water soluble inorganic ions in Wuhan are from two sources, coal, biomass combustion and dust, and the main source of carbon components is from coal burning, gasoline car tail. Gas and biomass combustion. The water-soluble inorganic ions in Guangzhou mainly come from two sources, biomass combustion, dust and coal combustion. The carbon components are mainly from coal, motor vehicle exhaust and biomass combustion. Burning and improving the coverage of green vegetation should become an important means to improve the atmospheric environment quality in the Middle East region.
【学位授予单位】：南京大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X513

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