节点文献
西安市大气中PM2.5及其碳气溶胶污染特征研究
Characteristics Analyze of Atmospheric Particles PM2.5 and Carbonaceous Aerosol in Xi’an
【作者】 陶李；
【导师】 张承中；
【作者基本信息】 西安建筑科技大学 ， 环境工程， 2011， 硕士
【摘要】 本文在西安市南郊,利用TEOM（?）系列RP-1400a环境颗粒物监测采样仪,对2009.122010.11期间西安市大气中PM2.5进行实时监测和采样分析。研究了PM2.5质量浓度的年、月及高分辨率日循环变化特征,分析了其与气象要素变化的关系,同时对不同季节PM2.5中碳气溶胶组分污染特征进行了分析研究。研究期间PM2.5年均值为90.5μg/m3。PM2.5质量浓度呈现出明显的时间序列变化,秋、冬季节变化幅度大于春、夏两季,7月份PM2.5质量浓度均值为61.37μg/m3,为全年PM2.5质量浓度最低月份,1月份PM2.5污染最为严重,PM2.5质量浓度均值达到143.29μg/m3,降水量较多的月份PM2.5质量浓度较低。四季PM2.5日循环变化均呈现明显的双峰模式,交通源的污染排放对监测点PM2.5影响明显,各个季节下午时间PM2.5浓度均呈明显下降的趋势,污染较轻,下午时段内温度较高,湿度较小,风速较大的气象条件有利于PM2.5污染物的扩散。春节期间大量烟花爆竹的燃放能够形成瞬时大气中PM2.5浓度的迅速升高,造成重度的PM2.5污染,春季严重的沙尘天气会形成PM2.5高浓度污染。OC、EC的年均值分别为23.04μg/m3、6.15μg/m3, OC和EC的浓度值冬季明显高于春、夏、秋三季,冬季OC/EC的值最大。TCA年均值为43.01μg/m3,占PM2.5质量浓度的43.5%,可见碳气溶胶是西安市PM2.5的重要组分。四季PM2.5中TCA和OC日时段变化呈现较好的早晚双峰分布特征,OC的日时段变化幅度较大, EC和WSOC的日时段变化幅度较小,冬、春、夏三季OC浓度在9:0012:00时段出现最大值,秋季OC在21:0023:00时段出现最大值。OC/EC值在各个季节均呈现在交通高峰时段值较小,下午时段值较大的变化规律。全年中OC与EC的相关性较好,说明西安市OC与EC的来源比较一致,四个季节中WSOC与OC呈较好的正相关关系,WSOC与OC的来源相似,WSOC与EC的相关性明显小于与OC的相关性,WSOC与EC的来源差异较OC大。
【Abstract】 In this paper, we collected the PM2.5 real time mass concentration dates and filter samples using a TEOM 1400a ambient particulate monitor at the station point of Xi’an University of Architecture and Technology during the period of Dec 2009 to Nov 2010. In this study, the characteristics of the annual, months and high-resolution diurnal variations of PM2.5 mass concentration and its relationship with meteorological was analyzed. It also analyzes the characteristics of carbonaceous aerosol of different seasons.The annual average concentration of PM2.5 was 90.5μg/m3 during the study period. The time series of PM2.5 concentration is obvious. Winter and autumn variations range are widely than other seasons. In July, the average PM2.5 concentration is lowest of the year with the concentration of 61.37μg/m3, while January is the highest PM2.5 concentration of 143.29μg/m3. It seems that the more rainfall has the lower PM2.5 concentration.The diurnal cycle of PM2.5 concentrations in four seasons are all display evident bi-modal patterns. Traffics pollutions have more influence on the PM2.5 of the study station point. In the afternoon, the PM2.5 concentration decline obviously, in the afternoon, PM2.5 displays low concentration. So the high temperature, low RH, high wind speed in the afternoon can make contribute to dilute the particular pollutions. A lot of fireworks during spring festival days can cause serious PM2.5 pollution in a short time. Sand weather in spring can also cause serious PM2.5 pollution.The annual average OC and EC concentrations are 23.04μg/m3 and 6.15μg/m3 respectively. in winter , the OC and EC concentrations are higher than other seasons. The annual average TCA concentration during the study period is 43.01μg/m3, it account 43.5% of PM2.5. TCA is the main component of PM2.5.The diurnal cycle of carbonaceous aerosol in four seasons also display bi-modal patterns. OC various higher than EC and WSOC. In winter, spring and summer, OC concentration display max value during 9:0012:00, while in autumn, OC concentration display max value during 21:0023:00. OC/EC value always displays lower value during traffic times, but in afternoon displays higher value.In the whole year, OC and EC have good correlation, the OC and EC in Xi’an has the similar source. WSOC and OC display good correlation, WSOC and OC has the similar source. WSOC and EC is not obvious than OC, so the source of WSOC and EC may be some different.
【Key words】 PM2.5； carbonaceous aerosol； diurnal cycle； time various； source analysis；