Steel production is an important source of particulate matter emission. In this study, both filterable and condensable fine particulate (PM 2.5 ) emissions from an electric arc furnace (EAF) and four integrated iron and steel plants were measured. Chemical compositions including water soluble ions and metal elements of these two types of PM 2.5 were analyzed. The results show that filterable PM 2.5 concentrations emitted from sintering, coke making, blast furnace, basic oxygen furnace (BOF) and EAF are 1.01, 0.37, 0.16, 0.15 and 0.28 mg/Nm 3 , respectively. Sintering has the highest filterable PM 2.5 emission concentrations. Condensable PM 2.5 concentrations emitted from the above processes are 65.3, 89.7, 3.84, 1.32 and 2.02 mg/Nm 3 , respectively, which are much higher than filterable PM 2.5 . K, Fe, Pb and Zn concentrations are high in filterable PM 2.5 for sintering process, which is attributed to the feedstocks of recycled materials. High sulfur content of the feedstocks results in high concentrations of SO 4 2-for all the test plants. In addition to Fe, the emissions of Pb, Zn and Sn are high for EAF, which is due to the complexity of the recycled steel feedstock for EAF. SO 4 2-is the highest emission ion for sinter process and coke making. For blast furnace, BOF and EAF, however, Na + , K + and Cl -are the predominated ions. For metal elements, concentrations of Na and K are highest for all the plants, which might be caused by their high potential of vaporization.

PM 2.5 emissions from stationary sources contain a filterable and condensable portion. In this study, USEPA Method 201A/202 are used to measure filterable and condensable PM 2.5 emissions from 5 stationary sources (power plants, boilers, brick manufacturing plant, incinerators and arc furnaces). The average filterable PM 2.5 concentrations for power plant, boiler, brick manufacturing plant, incinerator and arc furnace are 0.75, 16.9, 8.67, 0.15 and 2.12 mg/Nm 3 , respectively. The amount of PM 2.5 residue on the exit tube of cyclone and front half of the filter holder is significantly higher when the filterable PM 2.5 concentrations are low. It is necessary to collect both filter and the residue particulates to avoid underestimation of PM 2.5 emissions. The condensable PM accounts for 61.2%, 73.5%, 44.2%, 52.8% and 51.2% of total PM 2.5 for power plant, boiler, brick manufacturing plant, incinerator and arc furnace plant, respectively. The real PM 2.5 contribution to the atmosphere would be underestimated if condensable PM is not included. The condensable PM fraction increases as the exhaust temperature rises. The inorganic fraction accounts for 89.0%, 69.4%, 72.3%, 89.8% and 72.8% of condensable PM, respectively, for power plant, boiler, brick manufacturing plant, incinerator and arc furnace. The inorganic fraction is dominant in the condensable PM, which might be due to the high content of SO 4 .

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