The Contribution Of China’s Iron And Steel Industry To Air Pollution And Analysis Of Emission Mitigation Strategies

China has experienced serious fine particulate matter(PM_2.5)pollution in recent years,and carbon dioxide（CO₂）emissions must be controlled so that China can keep its pledge to reduce CO₂ emissions by 2030.The iron and steel industry（ISI）is energy intensive and contributes significantly to PM_2.5.5 pollution and CO₂ emissions in China.In this study,we used a pure backward linkage（PBL）method to quantify emissions from industries upstream of the ISI,conducted a cross-disciplinary research combining the Weather Research and Forecasting with Chemistry（WRF-Chem）model,the multiregional input-output model（MRIO）and the health assessment model to explore the impacts of the ISI on air pollution in a typical region（the BTH region）,evaluated how the downstream industries drive the outputs of the ISI and used a multi-objective analysis to compared potential technology combinations based on various policy preferences and targets.We find that the emissions from industries upstream of the ISI are generally higher than the production-based emissions of ISI by more than a factor.Furthermore,much of the upstream emissions of ISI are embodied in the interregional trade,transferring substantial emissions from the eastern region to inland provinces.Our results show large increases in air pollution due to direct ISI emissions,with up to a90μg/m³ monthly average of fine particulate matter(PM_2.5)and sulfur dioxide（SO₂）in eastern Tangshan and western Handan during wintertime.In addition to direct emissions,the ISI has induced large quantities of indirect emissions from upstream sectors（e.g.,the electricity and transportation sectors）,leading to PM_2.5,SO₂ and NO_x increases of 2-10μg/m³ in the BTH region.Considering the direct and indirect emissions,we estimated that275（233-313）PM_2.5-related premature deaths occurred in January,and approximately 42%of these premature deaths occurred in Tangshan.A high rate of premature deaths also occurred in urban Beijing due to its high population density.Regarding the drivers of ISI,our results reveal that consumption-based accounting underestimates the importance of many sectors.From the perspective of the consumption-based accouting,construction and export were the two major drivers to the emission from ISI.However,using the PBL methods,we found that the output of general equipment sectors and transportantion equipment sectors sectors could drive about 40%of the emissions from the ISI.The results also revealed that policies designed to mitigate PM_2.5.5 pollution have substantial co-benefits for CO₂ emissions reductions.However,policies focused solely on reducing CO₂ emissions fail to effectively reduce PM_2.5.Furthermore,CO₂ emissions reductions correspond to large financial costs,whereas PM_2.5.5 pollution reductions are less expensive.