深圳大气中VOCs的二次有机气溶胶生成潜势

使用气溶胶生成系数法和产率法,对深圳四季5种芳香烃和异戊二烯所生成的二次有机气溶胶(SOA)量分季节计算并比较得出:四季中除春季外,其余三季产率法计算得到的SOA量均高于生成系数法计算的结果,四季所生成SOA的平均值分别为(2.48±2.02)μg/m3和(2.10±1.21)μg/m3.2种方法计算结果均为夏季SOA的生成量最大,秋季和冬季次之,春季最小.生成系数法计算得出人为源和天然源的贡献分别为96%和4%,而产率法得到两种源的贡献分别为86%和14%.将生成系数法和产率法计算得到的夏季SOA值与实测值进行比较,发现计算值均低于实测值,分别占实测值的21%和31%.最后计算芳香烃和异戊二烯的自由基反应速率得出,与OH自由基反应是其生成SOA最主要的途径,比例为75%,与NO3自由基和O3的反应比例分别为22%和3%.在生成SOA速度上,苯乙烯的速度最快,苯的速度最慢.

The generation potential of secondary organic aerosol of atmospheric VOCs in Shenzhen

Both the fractional aerosol coefficients (FAC) and yields (Y) methods was wsed to calculate the secondary organic aerosol (SOA) production from atmospheric volatile aromatics and isoprene in ShenZhen. Throughant the year results from the Yields method were all larger than the results by the FAC method except in spring, and the total average SOA production values were (2.48±2.02) μg/m3 and (2.10±1.21) μg/m3. The calculated SOA value in the summer was the largest, followed by in the autumn, winter, and spring. By the FAC method, the contribution from anthropogenic sources was 96%, while the contribution from natural sources was 4%. By the Yields method, contributions of anthropogenic and natural sources were 86% and 14%, respectively. During summer time, the calculated SOA values by the FAC and Yields methods only accounted for 21% and 31% of the measured SOA value. The OH radical reaction activities of aromatic hydrocarbons and isoprene were also calculated, and the results showed that the aromatic hydrocarbons' reaction with OH radicals was the main source of SOA with a percentage of 75%, while the percentages of NO3 and O3 were 22% and 3%. In terms of generating speed of SOA, styrene was found to have the fastest speed, while the speed of benzene was the slowest.