摘要
2013年2月1日至3月20日、2013年7月10日至8月10日对成都市大气中细颗粒物(PM2.5)进行连续监测,同步记录气象数据。将PM2.5质量浓度与城市气象条件进行相关性分析,研究气象条件对PM2.5质量浓度的影响。2月1日至3月20日PM2.5质量浓度平均为147.38μg/m3,7月10日至8月10日平均为50.19μg/m3,大气细颗粒物污染最严重的时间出现在2月1—6日。成都市各气象条件中,PM2.5质量浓度与能见度、风速呈现显著负相关,而与其他气象要素相关性较弱,降水对PM2.5质量浓度影响也很大。改善城市通风有利于成都市大气中PM2.5的稀释和消散。通过建立3D模型并运用计算流体力学(CFD)软件模拟成都市选定的一处密集的建成区域,分析城市空间形态对通风的影响。研究发现,在假设等温的情况下,多层密集的区域对城市通风影响小,而高层对城市通风影响很大,建筑高度相近的街道与风向平行的风速大于与风向成角度的,与风向平行的街道沿线为高层的风速高于沿线为多层的,较大的开敞空间及背景风速更有利于城市通风环境。
The atmospheric fine particulate matter （ PM2.5 ） were simultaneously monitored in two periods from February 1 st to March 20th and July 10th to August 10th of 2013 in Chengdu, and main meterological parameters were collected. The relationship between PM2.5 mass concentrarion and meteorological conditions were analyzed to study the effect of meteorological conditions on PM2.5 mass concentrarion. The average concentration of PM2.5 was 147.38 μg/m3 from February 1th to March 20th and 50.19 μg/m3 from July 10 th to August 10 th , the atmospheric fine particulate pollution was most serious in February 1 st to 6 th . PM2.5 mass concentrations showed significant negative correlation with the visibility and wind speed, and weak correlation with other meteorological parameters. Precipitation also had a big impact on the mass concentration of PM2.5 . Improving urban ventilation was good for the dilution and dispersion of PM2.5 . A three-dimensional computational fluid dynamics（ CFD） model was developed to simulate a densely built-up area in Chengdu and analyzed the effect of urban spatial morphology on ventilation. The results indicated that under the assumption of isothermal, multi-storey buildings intensive region had a small impact on urban ventilation and the high-rise area had a great impact on ventilation. The streets which had similar height buildings when paralled to the wind direction had a greater wind speed than angled. Street paralled to the wind direction when filled with high-rise buildings had a greater wind speed than filled with multi-storey buildings. Large open space and ambient wind speed were more conducive to urban ventilation.
出处
《中国环境监测》
CAS
CSCD
北大核心
2014年第4期93-99,共7页
Environmental Monitoring in China
关键词
PM2
5
气象条件
空间形态
meteorological condition
spatial morphology
