2013年北京市PM_(2.5)的时空分布

Spatial-temporal characteristics of PM_(2.5) in Beijing in 2013

对2013年北京市35个自动空气质量监测子站的PM2.5数据进行分析,探讨PM2.5的时间分布特征、空间分布特征以及与前体物和大气氧化性的相关性关系。结果表明,PM2.5浓度由高到低的季节依次是冬季、春季、秋季和夏季,平均浓度分别为122.8μg·m-3、85.1μg·m-3、84.9μg·m-3和79.1μg·m-3;各类监测站中浓度由高到低的依次是交通站、城区站、郊区站和区域站,平均浓度分别为102.2μg·m-3、91.8μg·m-3、89.1μg·m-3和88.7μg·m-3。PM2.5月均浓度呈波浪型分布,在1月份、3月份、6月份和10月份各出现一个峰值。全年来看,交通站PM2.5的日变化规律呈单峰型分布,其他站点呈双峰型分布。分地区来看,年均PM2.5浓度由高到低的依次是东南部、西南部、城六区、东北部和西北部。PM2.5浓度与NO2、SO2和OX浓度均为显著正相关,表明前体物和大气氧化性对PM2.5浓度有显著影响。

Data of PM2.5from 35 automatic air quality monitoring stations of Beijing in 2013 were analyzed to examine the temporal and spatial characteristics of PM2.5and the correlation between PM2.5and its precursors and atmospheric oxidation.The results showed that the average concentrations of PM2.5in different seasons decreased in the order of winter,spring,autumn and summer,which were 122.8 μg· m^-3,85.1 μg· m^-3,84.9 μg· m^-3 and 79.1 μg· m^-3,respectively.The average concentrations of PM2.5at different stations decreased in the order of traffic station,urban station,suburban station and regional station,which were 102.2 μg · m^-3,91.8 μg · m^-3,89.1 μg · m^-3 and 88.7 μg · m^-3,respectively.Monthly average concentrations of PM2.5showed a wavy-shaped curve,the peaks of which appeared in January,March,June and October,respectively.For the whole year,diurnal variation of PM2.5at traffic station showed a single-peak curve,while other stations showed bimodal curves.Annual average concentrations of PM2.5in different regions decreased in the order of southeast,southwest,center（six districts）,northeast and northwest.Concentrations of PM2.5were significantly positively correlated with those of NO2,SO2 and OX,which indicated that precursors and atmospheric oxidation had a significant impact on the concentration of PM2.5.