都市エアロゾル,降水中の炭化水素の組成と季節変化

概要

論文の詳細を見る
In order to understand the source and behavior of organic matter in urban atmosphere, normal alkanes (C15-C43 ; 31-320 ngm^<-3>), hopanoid hydrocarbons (C29-C32 : 0.7-15 ngm^<-3>) and unresolved complex mixture of hydrocarbons (UCM : 270-3000 ngm^<-3>) were determined in urban and rural aerosols as well as rainwaters by using capillary GC and GC-MS. Total carbon and nitrogen contents were also determined in the aerosols. During spring to summer seasons, n-alkanes in Tokyo aerosols were dominated with higher plant-derived species such as C27, C29 and C31, whereas they were overwhelmed in winter by anthropogenic hydrocarbons with no odd/oven carbon number predominance. Hopanoid and UCM hydrocarbons mainly derived from petroleum combustion residue, showed higher concentrations in winter, however, their concentrations significantly decreased in new year holidays. The results of urban rainwater samples indicated distributions similar to aerosols. Time series rainwater samples showed that their concentrations decreased as a function of time, indicating a continuous wet scavenging of particulate organic matter. However, odd/even ratios (CPI) of n-alkanes and n-alkanes/ UCM ratios showed a gradual decrease during precipitation event, suggesting a preferential scavenging of plant-derived n-alkanes over anthropogenic hydrocarbons, the former being enriched in coarser particles.
1995-05-29