衡阳市区大气颗粒物的污染特征及环境安全评价

发布时间：2018-04-14 13:09

本文选题：衡阳市区 + 大气颗粒物　；参考：《南华大学》2015年硕士论文

【摘要】：随着经济的迅速发展,人口密度也快速增加,向大气环境排放的污染物也不断增加。空气颗粒物是大气污染物之一,其危害不仅与颗粒物浓度、粒径有关,而且受到所吸附的化学成分的影响,颗粒物中所含重金属对人体和环境的影响不容忽视。本文以衡阳市区作为研究对象,于2014年4-5月在四个典型的城市功能区设置采样点,收集可吸入颗粒、TSP、PM2.5样品。利用空气动力学原理、重量法、火焰原子吸收法、原子荧光法、Tessier连续提取法分析了其粒径分布、质量浓度、重金属含量和重金属的形态分布特征,并采用单因子评价法和内梅罗综合污染指数法等方法进行评价,得到以下结论:(1)衡阳市区粒径范围为0.500-10.366 um的颗粒平均总数量为每立方米空气中152.089个,平均总质量浓度为86.81ug/m3,可吸入颗粒的质量浓度和数量主要分布在细颗粒物上。(2)TSP的质量浓度平均值为230.8μg/m3。TSP平均质量浓度:工业区商业区交通干线民教生活区。部分样品的质量浓度超过环境空气质量标准(GB3095-2012)所规定的二级标准(300μg/m3)。采样期间PM2.5的质量浓度平均值为118.9μg/m3。PM2.5平均质量浓度:工业区民教生活区商业区交通干线。24个样品中有20个样品的质量浓度超过环境空气质量标准(GB3095-2012)所规定的二级标准(75μg/m3)。雨水冲刷可以使TSP浓度大幅度降低。而PM2.5会随着相对湿度的增加,PM2.5的质量浓度逐渐减小。采样点PM2.5与TSP质量浓度的比值平均值为51.52%,悬浮颗粒物主要以细颗粒物为主。(3)TSP与PM2.5样品中重金属浓度大小顺序为:PbCuAsCdHg。TSP与PM2.5样品中均有部分样品的As、Cd浓度高于环境空气质量标准(GB3095-2012)中规定环境空气中参考浓度限值(As为0.06 ug/m3,Cd为0.05 ug/m3),工业区超标样品较多;各种重金属含量的PM2.5/TSP值均大于其大气颗粒物质量浓度PM2.5/TSP值,重金属更容易富集在细颗粒物中。(4)TSP和PM2.5四种重金属单项污染指数达到安全等级的样品所占总样品数的百分比趋势相同:HgPbCdAs,四个功能区重金属的单项污染指数大小顺序均为:AsCdPbHg。内梅罗综合污染指数评价所采样品,处于安全和尚清洁级别的样品占总量的比例TSP和PM2.5分别为41.67%和83.33%,超过背景值的样品分别为50%和12.5%,处于中度污染和污染严重的样品很少,且都是从工业区采得。(5)形态分析显示TSP与PM2.5中重金属的形态分布呈现相同的趋势,As、Hg主要以残渣态F5形式存在,较为稳定,对人类健康和周边环境的影响较小。Pb、Cd、Cu在(F1+F2+F3+F4)中存在较多,容易发生转移。TSP与PM2.5中所含重金属的生物有效性由强到弱顺序均为:CdPbCuAsHg,其中Cu、Hg元素的生物有效性TSP强于PM2.5,而Pb、Cd、As元素的生物有效性PM2.5强于TSP。Pb、Cd、Cu、As为潜在生物可利用性元素,Hg为生物不可利用性元素。
[Abstract]:With the rapid development of economy, the population density is increasing rapidly, and the pollutant emission to the atmosphere environment is also increasing.Air particulate matter is one of the air pollutants. Its harm is not only related to particle concentration and particle size, but also affected by the adsorbed chemical composition. The effects of heavy metals in particulate matter on human body and environment can not be ignored.In this paper, Hengyang urban area was used as the research object. Sampling points were set up in four typical urban functional areas in April-May 2014 to collect TSPP PM2.5 samples of respirable particles.The particle size distribution, mass concentration, heavy metal content and speciation of heavy metals were analyzed by means of aerodynamics, gravimetry, flame atomic absorption spectrometry and Tessier continuous extraction.By using single factor evaluation method and Nemero comprehensive pollution index method, the following conclusions are obtained: the average total number of particles in Hengyang city is 152.089 per cubic meter of air, where the particle size ranges from 0.500 to 10.366 um.The average total mass concentration was 86.81ugp / m3. The mass concentration and quantity of inhalable particles were mainly distributed on fine particles. The average mass concentration of tsp was 230.8 渭 g/m3.TSP.The mass concentration of some samples exceeds the second class standard (300 渭 g / m ~ (3)) specified by the ambient air quality standard GB3095-2012.The average mass concentration of PM2.5 during sampling period is 118.9 渭 g/m3.PM2.5: traffic trunk line in commercial district of Minjiao living district in industrial area. Twenty out of 24 samples have mass concentration exceeding 75 渭 g / m ~ (3) specified in Ambient Air quality Standard (GB3095-2012).Rain Water can reduce the concentration of TSP by a large margin.However, the mass concentration of PM2.5 decreased with the increase of relative humidity.The average value of mass concentration of PM2.5 to TSP was 51.52, and the concentration of heavy metals in tsp and PM2.5 samples was in the order of:% PbCuAsCdHg.tsp and PM2.5 samples. The concentration of Ash CD in some samples was higher than that in ambient air.In the quality standard GB3095-2012, the limit value of reference concentration in ambient air is 0.06 ugm3Cd-0.06 ug-m3Cd-0.05ugm3N, and there are more samples in industrial area.The PM2.5/TSP value of heavy metal content was higher than the PM2.5/TSP value of atmospheric particulate mass concentration.Heavy metals were more easily enriched in fine particles. The percentage trend of heavy metals in the total number of samples with the four heavy metal pollution indexes reaching the safety grade was the same as that in the four functional regions, and the order of the single pollution index of the four functional regions was: 1% AsCdPbHg.According to the Nemero Comprehensive pollution Index, the proportion of the samples in the safety and cleanliness level was 41.67% and 83.33% of the total samples, respectively, while the samples exceeding the background value were 50% and 12.5%, respectively, and the samples with moderate and serious pollution were very few, and the proportion of the samples at the level of safety and cleanliness was 41.67% and 83.33%, respectively.The speciation analysis showed that the speciation distribution of heavy metals in TSP and PM2.5 showed the same trend, mainly in the form of residual F5, which was relatively stable.The effect on human health and the surrounding environment is less. PbCU is more common in F _ 1 F _ 2 F _ 3F _ 4.The bioavailability of heavy metals in tsp and PM2.5 is in the order of: CdPbCuAsHg, in which the bioavailability of CuPbCuAsHg is stronger than that of PM2.5.The bioavailability of PM2.5 is stronger than that of PM2.5.HG is a bioavailability element.
【学位授予单位】：南华大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X513;X823

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