Quantitative determination of the biomass-burning contribution to atmospheric carbonaceous aerosols in Daejeon, Korea, during the rice-harvest period

To investigate the impact of biomass-burning emissions on atmospheric carbonaceous aerosols, the biomass burning tracers; levoglucosan, mannonsan, galactosan, and K+ were measured at a suburban site in Daejeon, Korea, during the rice-harvest period, during the fall, 2012. The emissions of K+ from biomass burning (K+_BB) were estimated by subtracting sea-salt K+ and soil K+ concentrations from measured K+ concentrations. Regression analysis of levoglucosan and K+_BB reveals that K+_BB alone is not suitable as a biomass-burning tracer in the Daejeon atmosphere, especially when the biomass-burning contribution is low. Levoglucosan to K+_BB ratios during the study period ranged from 0.40 to 1.39, with an average of 0.89 ± 0.30, whereas levoglucosan to mannosan ratios ranged from 4.61 to 15.45, with an average of 6.70 ± 2.69. The ratios of levoglucosan to mannosan, K+, organic carbon (OC), and elemental carbon (EC) show that biomass-burning aerosols in the Daejeon atmosphere during the rice-harvest period are emitted mainly from crop residue, grass, and leaf burnings. The contributions of biomass-burning emissions to OC and EC concentrations were 45% ± 12% and 12% ± 7.3%, respectively, indicating that a large fraction of OC was emitted from biomass burning.