Characterization and emission factors of carbonaceous aerosol from coke production in China

Abstract Coking is a substantial source of carbonaceous aerosol in China, but the emission characteristics and pollution levels of carbonaceous aerosol in the coking process are still unknown, leading to considerable uncertainty in emission estimates. In this study, the emission factors of organic carbon (EFOC) and elemental carbon (EFEC) from typical coking plants were measured in Shanxi, China. The measured EFEC and EFOC from fugitive emissions (7.43 and 9.54 g/t) were significantly higher than those from stack flue gases (1.67 and 3.71 g/t). Different technological conditions of coke production affect the emissions of organic carbon (OC) and elemental carbon (EC). For example, the total emissions from coke plants that use coke ovens with a height of 3.2 meters (m) were higher than those from plants that use ovens with heights of 4.3 and 6 m. EFOC and EFEC emissions from stamp charging were significantly higher than those from top charging. The δ13CTC), δ13COC, and δ13CEC values for fly ash during coking were −23.74‰ to −24.17‰, −23.32‰ to −23.87‰, and −23.84‰ to −24.14‰, respectively, and no obvious isotopic fractionation occurred between the initial fuel and its fly ash during coke production. Different EC/OC ratios from different emission pathways and their carbon isotope signature for coke production should be considered to precisely investigate sources of carbonaceous aerosols. The total EC and OC emissions from coke production in China were estimated to be 3.93 and 5.72 Gg in 2017, for which Shanxi, Hebei, and Shaanxi were the largest contributors.