泰山夏季 PM2.5中二元羧酸类 SOA 的分子组成及来源

Compositions and Sources of Summertime Dicarboxylic Acids and Related SOA in PM_(2.5) from Mt. Taishan

为研究泰山夏季大气PM_(2.5)中二元羧酸类化合物的浓度水平、分子组成及来源,于2014年7~8月在泰山山顶进行PM_(2.5)样品采集,分析其二元羧酸类化合物、生物源二次有机气溶胶的示踪物(异戊二烯、α-/β-蒎烯及β-石竹烯的氧化产物)、水溶性有机碳(WSOC)及无机离子.结果表明,泰山夏季PM_(2.5)中二元羧酸的总浓度为(376±189)ng·m-3,其中草酸(C2)的浓度最高,其次是丙二酸(C3)、丁二酸(C4)和壬二酸(C9).泰山地区二元羧酸总浓度高于海洋地区,但低于城市和其他高山地区,表明受人为污染影响较小.C2/C4、C3/C4和F/M比值表明二元羧酸主要来自光化学氧化,且氧化程度较深.C9占二元羧酸的相对含量、C9/C6和C9/Ph比值均高于城市、海洋与高山地区,表明泰山地区SOA主要受生物源的影响,而非人为源.通过与模式估算值的对比及相关性分析,进一步表明泰山夏季二元羧酸类SOA主要受当地生物源光化学氧化的影响.

To identify the compositions and sources of dicarboxylic acids and related SOA in Mt. Taishan, PM2. 5 samples were collected from July to August, 2004, and analyzed for dicarboxylic acids and related compounds, the tracers of biogenic secondary organic aerosol （ SOA） （ Isopene, α-/ β-Pinene and β-caryophyllene SOA tracers）, water-soluble organic carbon （ WSOC） and inorganic ions. The results showed that total dicarboxylic acids were （376 ± 189） ng·m ^- 3 , and C2 was the most abundant dicarboxylic acid, followed by C3 , C4 and C9 . The concentrations of diacids were more abundant than those in marine regions, but lower than those in urban and other mountainous areas, indicating that the atmosphere in Mt. Taishan was less influenced by anthropogenic pollution. C2 / C4 , C3 / C4 and F/ M ratios indicated that diacids were mostly produced by more intensive photochemical oxidation. The relative abundance of C9 to the total diacids, C9 / C6 and C9 / Ph ratios were higher than those in urban, marine and mountainous regions, further suggesting that SOA in Mt. Taishan atmosphere were mostly derived from biogenic sources rather than anthropogenic sources. Compared to the budgets of model and correlation analysis, it suggested that diacids and related SOA in Mt. Taishan were mostly derived from photochemical oxidation of local biogenic sources.