Emission Characteristics, Source Profiles, Inventories, and Future Emissions of Volatile Organic Compounds from the...

Volatile organic compounds (VOCs) from coke production originate from multiple stacks and fugitive sources. However, process-specific compositions and reactivities remain poorly characterized. Coke-oven chimney, topside, and near-plant ambient samples were collected from two newly commissioned large-scale top-charging coking plants, and 116 VOC species were quantified using gas chromatography-mass spectrometry/flame ionization detection (GC-MS/FID). During the sampled operating periods, the measurement-derived coke-oven-chimney VOC emission factors were 0.077 and 0.117 g/kg coke for Plants A and B, respectively. Their production-weighted estimate (0.097 g/kg coke) was used as a provisionalinput for the chimney component of the literature-integrated inventory. A 121-species composite profile was constructed by harmonizing measurements from this study with published profiles. Quantified values were retained, reported non-detects were assigned a value of zero, and unreported or unmeasured species were excluded from the species-specific mean calculations. Process- and species-resolved VOC emission inventories for 2012-2020 were developed using dynamic emission factors and plant-level activity data. Alkenes accounted for 61.3% of the measured VOC mass in the coke-oven-chimney samples. Oxygenated VOCs accounted for 52.02-60.97% of the total VOCs in the topside samples, although this enrichment is interpreted as indicative because field/transport blanks and compound-specific aldehyde storage-recovery tests were unavailable. National VOC emissions were 800.8 kt in 2020, with a 95% uncertainty interval of -43.3 to +71.8%. Coke-oven leakage and condensation and cooling contributed 33.4% and 29.2% of the emission-weighted ozone formation potential (OFP), respectively, whereas condensation and cooling, coke-oven leakage, and desulfurization contributed 84.7% to the secondary organic aerosol potential (SOAP). These indicators represent standardized formation potentials rather than modeled ambient ozone (O₃) or secondary organic aerosol (SOA) responses. Illustrative scenarios indicated larger emission reductions under stronger control pathways, although the projections remained conditional on coke demand and control-technology assumptions. The results identified fugitive leakage and aromatic-rich gas-purification processes as priorities for VOC mitigation.