Process-resolved characterization and plant-level inventory of multi-pollutant emissions from China's coking industry

Process-specific multi-pollutant emissions, trace-element phase partitioning, and long-term mitigation potential in China's coking industry remain insufficiently resolved. This study aimed to integrate process-resolved field measurements with a dynamic plant-level emission inventory and scenario analysis to identify major emission characteristics and mitigation priorities. Size-segregated particulate matter, water-soluble ions, and trace elements were measured at coal charging, coke oven flue gas, dry quenching, and coke pushing units in two representative enterprises. A plant-level inventory covering 307 enterprises during 2012-2024 was subsequently developed, and emissions were projected to 2050. Total PM concentrations ranged from 3.12 to 37.72 mg/m³, sulfate accounted for 28-59% of the measured ionic mass, and As and Cd were preferentially associated with PM_2.5. The operationally defined condensable fraction contributed 44.5-57.4% of total measured trace-element concentrations in coke oven flue gas. In 2022, national emissions were estimated at 159.8 kt PM, 66.6 kt SO₂, 82.3 kt NOx, 1,928.6 kt CO, 32.6 kt NH₃, 838.3 kt VOCs, 4.24 kt PAHs, and 707.6 t trace elements. Under the BACT scenario, PM, SO₂, NOx, and trace-element emissions were projected to decline to 15.5 kt, 14.6 kt, 7.4 kt, and 88.1 t, respectively, by 2050. These results identify process-, region-, and technology-specific priorities for controlling fine particles, condensable fractions, and fugitive emissions from China's coking industry.