基于在线监测的上海郊区冬季PM_(2.5)来源解析

PM_(2.5) source apportionment at suburb of shanghai in winter based on real time monitoring

利用1405F、Marga和Xact625在线监测仪于2013年12月23日至2014年2月18日期间对上海市青浦淀山湖地区PM2.5的质量浓度和化学组分进行了测定.结果显示:淀山湖地区冬季PM2.5平均质量浓度为85.1μg·m-3,高于国家环境空气质量年均二级浓度限值1.4倍,高出同期全市PM2.5平均浓度(65.5μg·m-3)30%.无机离子组分占PM2.5的比重为58.4%,其中二次离子NO-3、SO2-4和NH+4的含量最高,总体均值分别为(17.13±15.70)μg·m-3、(13.45±11.10)μg·m-3和(12.09±10.37)μg·m-3,分别占PM2.5浓度的20.1%、15.8%和14.2%.利用PMF方法对淀山湖地区PM2.5的来源解析结果显示:二次气溶胶、燃油、生物质燃烧/海盐、扬尘/建筑尘、燃煤/冶炼尘的贡献率分别为50.8%、17.5%、17.2%、7.7%和6.9%.

PM2.5mass concentration and chemical composition were monitored at Dianshan Lake,a western Suburb of Shanghai by real time analyzers（1405F,Marga and Xact625）from 23 rd Dec.2013 to 18th Feb.2014.The result showed that the average concentration of PM2.5at Dianshan Lake was 85.1μg·m^-3,1.4times higher than the PM2.5annual limit of the national ambient air quality standards of china,30% higher than the PM2.5 average concentration of Shanghai（65.5μg·m^-3）.Total inorganic ions accounts for 58.4% of PM2.5 mass concentration,secondary inorganic ions（NO3^-,SO4^2-and NH4^＋）were（17.13±15.70）μg·m^-3、（13.45±11.10）μg·m^-3 and（12.09±10.37）μg·m^-3,accounting for 20.1%、15.8% and 14.2% of PM2.5 mass concentration,respectively.Positive Matrix Factorization（PMF）model was performed to identify the source of PM2.5at Dianshan Lake.Five significant sources contributing to the observed PM2.5were：secondary aerosols,oil combustion,biomass burning/sea salt,fugitive dust and coal combustion/smelting dust,with the contribution of 50.8%,17.5%,17.2%,7.7% and 6.9% of PM2.5 mass concentra-tion,respectively.