西安市某地下停车场细颗粒物浓度分布特征

CONCENTRATION DISTRIBUTION CHARACTERISTICS OF FINE PARTICULATE FROM AN UNDERGROUND PARKING GARAGE IN XI'AN,CHINA

为了解地下停车场细颗粒物分布特征,通过连续监测西安市某地下停车场不同位置细颗粒物小时浓度并采集PM2.5和PM10样品,计算各测点PM2.5和PM10日均浓度。同时对停车场出入口每小时的车流量进行统计,分析细颗粒物浓度与车流量之间的关系。结果表明：该停车场进出车辆具有明显的时间规律,工作日上班高峰期07：00—09：00出口车辆较多,17：00—21：00入口车辆较多,休息日出口峰值出现在09：00—12：00,入口高峰期出现在19：00—23：00,其余时段进出车辆较少。各测点PM2.5小时浓度值在0.004-0.477 mg/m^3,平均为0.082 mg/m^3,日平均浓度在0.043-0.090 mg/m^3,平均为0.057 mg/m^3,PM10日均值浓度为0.083-0.348 g/m^3,平均为0.189 mg/m^3。停车场出入口细颗粒物浓度与车流量之间呈现正相关性,颗粒物浓度在出入口和车流经过频繁的点位较高且细颗粒物所占比重较小（〈35%）,车流量小的区域颗粒物浓度较低但细颗粒物比重较大（〉50%）。

In order to understand the fine particle distribution characteristics of underground parking,the particulate matter＇s（ PM）（ including PM2. 5and PM10） hourly concentration were monitored and samples were collected in different sites of an underground parking garage in Xi ＇an,Shaanxi Province. Simultaneously,in order to analyze the relation between PM2. 5concentration and traffic,the vehicle traffic of entrance and exit were recorded. The results showed that the vehicle flow rate was higher at the exit during 7： 00—9： 00 and at the entrance during 19： 00—21： 00 in workdays,while at the exit during9： 00—12： 00 and at the entrance during 19： 00—23： 00 in weekends. The hourly mass concentration of PM2. 5in different sites varied from 0. 004 - 0. 477 mg/m^3,the average value was 0. 082 mg/m^3,while its daily concentration was 0. 083 - 0. 348 g/m^3 whose mean value was 0. 189 mg/m^3. There was a positive correlation between traffic and fine particle concentration. The concentration of PM were higher at entrance,exit and the site with higher vehicle flow,when PM2. 5/PM10 ratio were all below35%; while at the sites with lower vehicle flow,the PM concentration were lower and the ratio PM2. 5/PM10 were all higher than 50%.