Historical inventories and future scenarios of multiple hazardous air pollutants (HAPs) emissions from the iron and steel production industry in China.

Iron and steel production (ISP) is one of significant atmospheric pollution emission sources in China. With the implementation of ultra-low emission (ULE) standards, a detailed and new updated emission inventory is urgently needed for better understanding of the temporal trends and spatial variation of emission characteristics. In this study, a unit-based comprehensive emission inventory of multiple hazardous air pollutants (HAPs) for the Chinese ISP spanned from 2012 to 2021, including the conventional pollutants, 13 kinds of Trace elements as well as 2 unconventional but toxic pollutants (PCDD/Fs, F), was dedicatedly developed by integrating dynamic localized emission factors with unit-based information of both the detailed activity level and abatement technology application. Scenario analyses were also conducted to forecast future emission trends up to 2050. The results showed that the lower emission factors owing to ULE retrofits had resulted in different spatial-temporal emission characteristics between outputs and HAPs emissions. The atmospheric emissions of SO, NO, PM, PM, TSP, F and PCDD/Fs from Chinese ISP in 2021 were estimated at about 414.4, 450.5, 1044.3, 2001.6, 3958.8, 9.42 kt and 9.35 kg-TEQ, respectively. And most HAPs emissions were lower than those in 2012. Regarding the spatial distribution, Hebei, Jiangsu, Shanxi, ranked as the top 3 emission provinces. Moreover, different manufacturing processes (sintering, blast furnace, steel making, etc.) contributed with different magnitude for specific species, and the future trends estimation showed a great reducing potential caused by the implementation of ULE abatement measures and structure adjustment in future.