In order to understand the relative importance of anthropogenic and biological sources of carbonaceous aerosols in Northeast Asia,we measured total carbon(TC)and water-soluble organic carbon(WSOC)and their stable carbon isotope ratios(d~(13)C)in total suspended particulates collected from Sapporo,northern Japan(43.07°N,141.36°E)over a 1-year period(during 2 September 2009and 5 October 2010).Temporal variations of TC showed a gradual decrease from mid-autumn to winter followed by a gradual increase to growing season with a peak in early summer.Both d~(13)C_(TC)and d~(13)C_(WSOC)showed very similar temporal trends with a gradual enrichment of~(13)C from mid-autumn to winter followed by a depletion in the~(13)C to early summer and thereafter it remained stable,except for few cases.Based on the results obtained together with the air mass trajectories,we found that biogenic emissions including biological particles(e.g.,pollen)and secondary organic aerosol formation from biogenic volatile organic compounds are the important sources of carbonaceous aerosols in spring/summer whereas fungal spores from soil and biomass burning and enhanced fossil fuel combustion contribute significantly in autumn/winter and in winter,respectively,in Northeast Asia. In order to understand the relative importance of anthropogenic and biological sources of carbonaceous aerosols in Northeast Asia, we measured total carbon (TC) and water-soluble organic carbon (WSOC) and their stable carbon isotope ratios (d ~ (13) C) in total suspended particulates collected from Sapporo, northern Japan (43.07 ° N, 141.36 ° E) over a 1-year period (during 2 September 2009 and 5 October 2010). Temporal variations of TC showed a gradual decrease from mid-autumn to winter followed by a gradual increase to growing season with a peak in early summer.Both d ~ (13) C_ (TC) and d ~ (13) C_ (WSOC) showed very similar temporal trends with a gradual enrichment of ~ (13) C from mid -autumn to winter followed by a depletion in the ~ (13) C to early summer and thereafter it remains stable, except for few cases. Based on the results obtained together with the air mass trajectories, we found that biogenic emissions including biological particles ( eg, pollen) and secondary organic aerosol formation from biogenic volatile organic compounds are the important sources of carbonaceous aerosols in spring / summer versus fungal spores from soil and biomass burning and enhanced fossil fuel combustion contribute significantly in autumn / winter and in winter, respectively, in Northeast Asia.