In an attempt to elucidate sources of combustion to EC and other incomplete combustion products, we investigated seasonal variations of PAHs and molecular markers for biomass burning (levoglucosan: LG, dehydroabietic acid: DH and retene) in fine particulate mountain aerosols at the 1100 m declive of Mt. Halla, Jeju Island, Korea. PAHs observed at the site (sum of 3-6 ring parental PAHs: 0.05-7.8 ng/m³) were mostly of combustion origin and showed an intense signal in winter and several minor maxima in summer. Observations of LG (0.3-840 ng/m³) and resin diterpenoid markers (DHA: 0.1-127 ng/m³, retene:2-80 pg/m³) throughout the year evidenced biomass to be a significant source of combustion to the study site. Combination of PAHs isomer pair ratios and biomass-burning tracers revealed that biomass-burning contributions intermittently overwhelmed that from fossil fuel combustion. The backward trajectory analyses showed that the intense signals of LG/PAHs ratio in fall-winter were dominated by airmass from island areas while those in summer were ascribed to selective loss of PAHs by photochemical process. On the other hand, DHA and retene spikes in summer were judged to be from local Pinaceae combustion sources. Strong influence of westerly for samples with intense signal of biomass burning (i.e., LG, LG/PAH ratio and PAHs isomer pair ratios) indicates that biomass is an important source of combustions in the inland of East Asia and its pyrolytic products are available for long-range transport in winter.