区域大气细粒子污染特征及快速来源解析

在广东大气超级站使用单颗粒气溶胶飞行时间质谱仪(SPAMS)等仪器开展综合观测,2013年12月共监测到两个污染过程,主要的化学成分为元素碳(EC),占总颗粒数的56.8%,其次为有机碳(OC)和重金属(HM),分别占总颗粒数的12.7%和10.1%.两个污染过程中,不同颗粒类别的变化趋势有差异,说明两个污染过程的污染特征有所不同.污染来源分析发现,监测期间主要受到机动车尾气源和燃煤源的影响,二者分别占24.8%和22%;其次为工业工艺源和生物质燃烧,分别占16.4%和10.3%.第一个污染过程中,工业工艺源是首要污染源,而随着颗粒物浓度的增高,燃煤和二次无机气溶胶的比例明显增加,说明此污染过程中受一次污染源(燃煤源和工业工艺源)和二次光化学反应的复合影响.而第二个污染过程中,机动车尾气为首要污染源,其次是燃煤和工业工艺源,整个过程中各源的比例较为稳定,说明该次污染过程主要由不利气象条件导致的污染物累积形成.

The pollution characteristics and source apportionment of regional atmospheric fine particles

Single particle aerosol mass spectrometer (SPAMS) was used to analyze the single particle characteristics of aerosols in Heshan, in December 2012. Two typical pollution processes were captured during the sampling period. The fine particles were dominated by elemental carbon (EC), which accounted for 56.8% of total particles. Organic carbon (OC) and heavy metal (HM) accounted for 12.7% and 10.1% of sampled particles, respectively. Different particle types showed different temporal profiles during the two pollution processes, indicating the characteristics of the two processes were different. The source apportionment results showed that the most important PM_2.5 sources in this region were vehicle emission and coal combustion, accounting for 24.8% and 22% of PM_2.5, respectively. Industry emission and biomass burning were also important, contributing 16.4% and 10.3% to total PM_2.5 particles, respectively. During the first pollution process, industry emission was the most important source, and the contribution of coal combustion and secondary inorganic aerosol were found to be increasing with PM_2.5 concentration, implying that primary emission as well as enhanced secondary photochemical reaction played important roles in the increasing of PM_2.5 concentration. However, vehicle emission was the most important source during the secondary pollution process, and the proportion of each source was stable during the whole pollution process, indicating this process was induced by the accumulation of pollutants under unfavorable meteorological conditions.