2016 年 31 巻 1 号 p. 47-58
Abstract To evaluate seasonal variations and sources of the carbonaceous components in aerosols emitted from biomass burning and vegetation in urban site, we measured organic carbon, elemental carbon, radiocarbon (14C) in total carbon (TC), and levoglucosan concentrations in total suspended particulate matter collected in Nagoya. Higher 14C concentrations were observed during spring (56.4 pMC) and summer–early fall (57.4 pMC) than during late fall–winter (47.1 pMC). In particular, 14C concentration in April was influenced by pollens, and it showed the highest 14C value (about 70 pMC) in our observations. Levoglucosan concentrations had clear seasonal variations: the contents from late fall–winter were higher than those in other seasons, similar to other reports in Japan. Moreover, levoglucosan had a good correlation with non-fossil carbon in total carbon (TCnf) calculated by 14C concentration, from early fall–winter. Furthermore, TCnf was roughly divided into two origins: biomass burning (TCbb) and biogenic carbon except for biomass burning (TCbio). The contributions of TCbb to TCnf and TC in late fall–winter were found to be the highest. Meanwhile, TCbio was higher than TCbb in all seasons, and the main sources of TCbio were considered to vary by seasons: pollens in spring and biogenic secondary organic aerosols in summer.