鞍山市春秋季PM_(2.5)中碳组分特征及来源

Characteristics and Source Apportionment of Carbon in PM_(2.5) During Spring-Autumn in Anshan

为研究鞍山市春秋季PM_(2.5)中碳组分的污染特征及来源,该文于2014年10月和2015年4月在鞍山市设立6个点位采集PM_(2.5)样品,并测定了其中有机碳(OC)和元素碳(EC)的含量。通过对鞍山市PM_(2.5)中OC和EC的浓度水平、OC与EC的相关性及比值、二次有机碳(SOC)的估算和主成分分析等进行研究,分析了鞍山市春秋季PM_(2.5)碳组分的污染特征和来源。结果表明,春季和秋季PM_(2.5)浓度的日均值分别为(94.28±10.27)μg/m^(3)和(118.60±12.92)μg/m^(3);春季PM_(2.5)中OC和EC的质量浓度分别为(12.44±1.53)μg/m^(3)和(3.80±0.74)μg/m^(3);秋季PM_(2.5)中OC和EC的质量浓度分别为(18.53±1.92)μg/m^(3)和(4.74±1.24)μg/m^(3),OC、EC在春秋季的差异具有统计学意义,各监测点位OC与EC浓度均表现为秋季高于春季;春季和秋季各点位的OC/EC值均大于2,说明各采样点位在春秋季均存在二次污染;相关分析表明,春秋季的OC与EC均显著相关,说明春秋季OC与EC来源相似;采用OC/EC最小比值法估算SOC含量,得到春季和秋季SOC浓度分别为4.65和10.37μg/m^(3);主成分分析结果表明,鞍山市大气PM_(2.5)中碳组分主要来源于燃煤、生物质燃烧、道路扬尘和机动车尾气。

To study the pollution characteristics and sources of carbon in PM_(2.5),PM_(2.5) samples were collected at six sites in Anshan in October,2014 and April,2015.And the contents of OC and EC in PM_(2.5) were measured.The pollution characteristics and sources of carbon components were obtained by analyzing the concentration levels of OC and EC,the correlation and ratio between OC and EC,the secondary organic carbon(SOC)values and principal component analysis.Results showed that the daily mean value of PM_(2.5) in spring and autumn were(94.28±10.27)μg/m^(3) and(118.60±12.92)μg/m^(3),respectively.The concentrations of OC and EC in PM_(2.5) in spring were(12.44±1.53)μg/m^(3) and(3.80±0.74)μg/m^(3);the concentrations of OC and EC in PM_(2.5) in autumn were(18.53±1.92)μg/m^(3) and(4.74±1.24)μg/m^(3).The differences of OC and EC in spring and autumn were statistically significant,and the concentrations of OC and EC at all sites were higher in autumn than in spring.The ratios of OC/EC were all larger than 2 in spring and autumn,indicating that there was secondary pollution at each monitoring station in spring and autumn.Spearman correlation analysis showed that OC and EC were significantly correlated in spring and autumn,which indicated that the emission sources of OC and EC were similar in spring and autumn.The minimum OC/EC ratio method was used to estimate the SOC formation,and the estimated SOC values in spring and autumn were 4.65μg/m^(3) and 10.37μg/m^(3).Based on principal component analysis,carbons in PM_(2.5) in Anshan were mainly from coal combustion,biomass burning,road dust and vehicle exhaust.