By sampling dioxins discharged from typical biomass combustion boilers (including large-, medium-, and small-scale) in southern region and undergoing sample pretreatment, the dioxin samples were analyzed by high-resolution gas chromatography/high-resolution mass spectrum (HRGC/HRMS). Data showed that the total average concentration of dioxin discharged by large-scale biomass combustion boiler was 40.8pg/m3, consisting of 4.85~20.6pg/m3 in particles and 21.3~45.2pg/m3 in gas phase, each of which was much lower than the discharge concentration from the medium-scale biomass combustion boiler, which was 2470pg/m3 in total average, 34.3~4074pg/m3in particles, and 99.6~3261pg/m3 in gas phase, respectively. Furthermore, the small-scale biomass combustion boiler had the highest dioxin discharge concentration, with 16234pg/m3 in total average, 441~43170pg/m3 in particles, and 776~5553pg/m3 in gas phase, respectively. The distribution characteristics of dioxin homologues in the flue gas of the biomass combustion boiler showed that HpCDF and OCDD constituted the major contribution to particle and gas phase dioxins in large-scale enterprise, with each percentage of 16.0%~44.7% and 14.0%~62.9%, respectively. However, HxCDF, HpCDF and PeCDF, HxCDF were the major contributor to the particle and gas phase dioxin concentration, the percentage reached to 10.0%~29.3%, 8.0%~20.9% and 12.4%~44.0%, 17.0%~31.4%. The I-TEQ distribution of dioxin in the biomass combustion boiler shows that the I-TEQ content of PCDFs was greater than that of PCDDs, where 2,3,4,7,8-PeCDF and 1,2,3,7,8-PeCDD were the major contributors to I-TEQ in dioxin of both particles and gas phase. Besides these two components, 2,3,7,8-TCDD was the third major contributor to I-TEQ in dioxin of gas phase. There was a significant linear relationship between the concentration of 2,3,4,7,8-PeCDF and the total concentration of dioxin (including the particle phase and the gas phase dioxin), with R2 of 0.999, 0.981 and 0.991, respectively, provided indicating information on the study of dioxin.
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