重庆市大气颗粒物时空分布及影响因素

发布时间：2019-01-07 07:07

【摘要】：大气颗粒物作为首要的大气污染物,对人体健康、环境等方面带来严重危害,目前已受到关注,许多研究者开展了大气颗粒物多方面的研究。本研究基于重庆市2013年～2015年17个空气质量监测站点数据,利用ArcGIS等工具分析重庆市大气颗粒物的时空分布特征；利用SPSS秩相关法分别探究气象因子、气态污染物对大气颗粒物的影响,以及对典型污染天气的作用；基于Trajstat后向轨迹模拟,分析重庆市不同季节及典型污染天气大气颗粒物的区域传输来源。主要结论如下：(1)在日际尺度上,PM2.5与PMlo浓度均呈现明显的双峰双谷曲线变化；在季节尺度上,大气颗粒物浓度变化趋势为冬季秋季春季夏季；观测时间内,共出现典型污染天气次数为11次,共计85天。(2)基于GIS空间分布研究表明,大气颗粒物浓度在重庆的分布呈由北部到南部逐渐递增的趋势,人口与交通密集,工商业发达的区域污染源排放量大,大气颗粒物浓度偏高。(3)气态污染物与大气颗粒物的关系密切。SO2、NO2是大气颗粒物的重要前体物,他们的浓度变化趋势相似；03与大气颗粒物的关系相对复杂,O3可以加快污染物的生成速度,大气颗粒物又具有降低大气光化学反应从而抑制03产生的作用。(4)在污染源一定的条件下,气象因子是影响大气颗粒物浓度变化的主要因素。一般来说,大气颗粒物与气压均呈正相关关系,而与风速、气温、相对湿度、降雨呈负相关关系。典型污染天气下,大气颗粒物浓度与气压、风速、气温、降雨呈负相关关系,与相对湿度呈正相关关系。典型污染多发生在低温、风速小、无降水或降水少、大气层结构稳定、逆温层厚度大的天气条件下。(5)重庆市受亚热带季风气候影响,大气颗粒物传输路径存在明显的季节差异性。从传输距离来看,短距离的区域传输轨迹占主要部分,表明重庆市大气颗粒物主要来自本地源排放。典型污染天气轨迹模拟结果显示区域间的污染输送现象明显,局地排放是主要的污染源,表现为区域环流控制的天气形势抑制大气颗粒物输送,不易向其它地区扩散转移,造成大气颗粒物在本地堆积,导致典型污染发生。
[Abstract]:As the primary atmospheric pollutant, atmospheric particulate matter has brought serious harm to human health and environment, and has been paid attention to. Many researchers have carried out research on atmospheric particulate matter in many aspects. Based on the data of 17 air quality monitoring stations in Chongqing from 2013 to 2015, the temporal and spatial distribution characteristics of atmospheric particulates in Chongqing were analyzed by means of ArcGIS and other tools. The effects of meteorological factors, gaseous pollutants on atmospheric particulates and typical polluted weather were investigated by SPSS rank correlation method. Based on the Trajstat backward trajectory simulation, the regional transport sources of atmospheric particulates in different seasons and typical polluted weather in Chongqing were analyzed. The main conclusions are as follows: (1) on the daytime scale, the concentrations of PM2.5 and PMlo show obvious bimodal and bimodal curves, and on the seasonal scale, the variation trend of atmospheric particulate concentration is winter, autumn, spring and summer; During the observation period, the number of typical polluted weather was 11, which was 85 days. (2) based on the spatial distribution of GIS, the distribution of atmospheric particulate matter in Chongqing was gradually increasing from the north to the south, and the population and traffic were dense. (3) the relationship between gaseous pollutants and atmospheric particulate matter is close. SO2,NO2 is an important precursor of atmospheric particulate matter, and their concentration change trend is similar; The relationship between 03 and atmospheric particulates is relatively complex. O3 can accelerate the formation rate of pollutants, and atmospheric particulates can reduce atmospheric photochemical reactions and thus inhibit 03. (4) under certain pollution sources, Meteorological factors are the main factors affecting the concentration of atmospheric particulates. Generally speaking, there is a positive correlation between atmospheric particulate matter and atmospheric pressure, but a negative correlation with wind speed, air temperature, relative humidity and rainfall. In typical polluted weather, the concentration of particulate matter is negatively correlated with air pressure, wind speed, temperature and rainfall, and positively correlated with relative humidity. Typical pollution occurs under the weather conditions of low temperature, low wind speed, no or less precipitation, stable atmospheric structure and large thickness of inversion layer. (5) Chongqing is affected by subtropical monsoon climate. There are obvious seasonal differences in the transport paths of atmospheric particulates. From the point of view of transmission distance, the short distance regional transport track accounts for the main part, which indicates that the atmospheric particulates in Chongqing mainly come from local source emissions. The simulation results of typical polluted weather track show that the pollution transport between regions is obvious, and the local emission is the main pollution source. The weather situation controlled by the regional circulation inhibits the transport of particulate matter in the atmosphere, and it is not easy to spread and transfer to other areas. Atmospheric particulates accumulate locally, leading to typical pollution.
【学位授予单位】：北京林业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：X513

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