典型污染源大气颗粒物、BC与VOCs的排放特征

Emission characteristics of particle matter, BC and VOCs fromtypical air pollution sources

为理解不同污染源产生的大气颗粒物、黑碳(BC)和挥发性有机物(VOCs)的排放特征,于民用燃煤烟气、餐饮油烟和施工扬尘条件下,对大气颗粒物质量浓度、BC和VOCs浓度以及颗粒物数浓度与质量浓度的粒径分布进行现场测量。结果表明,不同污染源排放的颗粒物、BC、VOCs浓度、颗粒物粒径分布及相关性差异明显。其中,燃煤烟气和施工扬尘排放的颗粒物质量浓度主要分布在粗粒子中,较小和较大粒径颗粒物的数浓度增加显著;而餐饮油烟排放的颗粒物质量浓度主要分布在微米级粒子中,1μm附近的颗粒物的数浓度大幅度增长。另外,燃煤烟气与餐饮烟气中的BC和VOCs主要来自燃烧与加热过程,与细颗粒物数浓度呈显著的正相关关系,伴随着细颗粒物产生;而施工扬尘中BC主要来自施工机械尾气与扬尘,与粗、细颗粒物均有显著的相关性,随着各种颗粒物的排放而排放。上述三类污染源中颗粒物、BC与VOCs的排放特征为大气污染来源识别提供了依据。

To understand the emission characteristics of particulate matter(PM),black carbon(BC),and volatile organic compounds(VOCs)from different pollution sources,in-situ measurements of the PM,BC,and VOCs concentrations as well as the size distributions of particle number and mass concentrations were conducted under the conditions of residential coal burning flue gas,cooking smoke,and construction dust.The results showed that there were obvious differences among different pollution sources in the PM,BC,and VOCs concentrations,the distribution of particle number and mass concentrations,and the correlations between different pollutants.For coal burning flue gas and construction dust,the PM mass mainly existed in coarse particles and there was significant increase in the number concentrations of both fine and coarse particles.However,in the cooking smoke,the particle mass mainly distributed in micron particles and the number concentrations of particles around one micrometer exhibited a sharp increase.In addition,BC and VOCs in the coal burning flue gas and cooking smoke were mainly produced from burning and heating processes.Their concentrations showed significant positive correlation with number concentrations of fine particles,suggesting they were emitted accompanying by fine particles.Nevertheless,as to construction dust,most BC came from construction machinery exhausts and fugitive dust.The BC concentration was strongly corelated with both fine and coarse particles,implying they were released with various particles.Overall,the emission characteristics of PM,BC,and VOCs from the above three sources provide basis for source identification of air pollution.