天津城区秋季PM2.5质量浓度垂直分布特征研究  

Vertical Distribution Characteristics of PM_(2.5) Mass Concentration in the Atmosphere over Tianjin

作　　者：孙玫玲[1,2] 穆怀斌[1] 吴丹朱[1] 姚青[1] 刘德义[3] 

机构地区：[1]天津市气象科学研究所,300074 [2]南开大学环境科学与工程学院 [3]天津市气候中心

出　　处：《气象》2008年第10期60-66,共7页Meteorological Monthly

基　　金：城市气象科学研究基金(UMF200607);天津市自然科学基金(08JCYBJC10200)

摘　　要：为研究天津大气颗粒物的污染水平和时空分布特征,利用天津大气边界层观测铁塔(255m),分别在40m、120m、220m处设立监测点,通过监测到的PM2.5的质量浓度,结合PM10、能见度等资料来分析污染物的时空分布规律和分布特征。结果表明,天津城区PM2.5污染水平相当严重,日均质量浓度远高于美国1997年制定的65μg.m-3的排放标准。混合层厚度和稳定度的变化对PM2.5浓度变化有一定的影响,随混合层厚度的变化,不同高度PM2.5质量浓度值有所不同。23时至11时,120m浓度明显高于其它各层,11—18时,由于大气扩散能力的增强,三层污染物质量浓度开始下降,而到了18—23时,低层污染物浓度较高,各层浓度总体趋势为120m>40m>220m。PM2.5质量浓度的日变化与稳定度的变化较一致。气象条件和早晚出行高峰期的影响导致PM2.5的质量浓度出现峰值。PM10与PM2.5的总体变化趋势基本一致,说明污染物来源基本相同。能见度水平和细粒子污染水平呈现较好的负相关,细粒子质量浓度的高低是决定能见度好坏的主要因子。降水过程是颗粒物从大气中清除的重要机制。From October 1-31, 2006, the research set 3 monitoring points respectively in 40-meter, 120-meter, 220-meter platforms and monitored the air quality with PM2.5 concentration. Combined with PM10 concentration and visibility range, the temporal and spatial distribution of pollutants was analyzed. The result indicated that PM2.5 concentration varies obviously at different vertical heights. The overall trend of pollutant distribution at three levels was 120-meter〉40- meter：〉220-meter. The mixing-layer depth and atmospheric stability is the most important factors to influence PM2.5 concentration. PM2.5 concentration also varied in different time as follows： from 23：00 to 11：00, the concentration in 120-meter platform was significantly higher than other levels; from 11：00 to 18：00, due to the enhancement of atmospheric diffusion capacity, the pollutant concentration at three levels started to decline; from 18：00 to 23：00, the pollutant concentration at lower level showed higher value. Everyday the PM2.5 mass concentration varied in a certain regular way. PM2.5 concentrations peak usually was caused by weather condition and traffic exhauster. And it also indicated that in Tianjin city the overall varying trend of PM10 and PM2.5 concentration seems the same, there was a negative correlation between the visibility range and the level of fine particles pollution. The precipitation process is the important mechanism of removing particle from atmosphere.

关 键 词：PM2.5 质量浓度 垂直分布 

分 类 号：X513[环境科学与工程—环境工程] TS207.3[轻工技术与工程—食品科学]