A unit-based emission inventory of SO2, NOx and PM for the Chinese iron and steel industry from 2010 to 2015.

It is important to understand the emission characteristics of PM and its precursors for the iron and steel industry in high resolution, considering its significant contribution to the total national emissions and the pressing need for more scientific and specific strategies of air pollution control in China. We developed a unit-based emission inventory of SO2, NOx, PM2.5, PM10 and TSP for the Chinese iron and steel industry from 2010 to 2015 by integrating source-specific unabated emission factors with unit-based information of both the activity rate and abatement technology from ~4900 production facilities in mainland China. This is the first study that accomplished a unit-based and source-specific emission inventory of SO2, NOx, PM2.5, PM10 and TSP updated to 2015 for the Chinese iron and steel industry. Based on our estimates, despite the rise of 26.1% in crude steel production from 2010 to 2015, the annual emissions of SO2, PM2.5, PM10, TSP were reduced by 27.9%, 27.4%, 36.1% and 50.4% respectively, and the NOx had increased by 12.4% for the Chinese iron and steel industry. The emissions of SO2 and PM from sintering, pelletizing, BF, BOF, and EAF all significantly decreased. Hebei, Jiangsu, Shandong, Liaoning, Shanxi, Henan, and Hubei are hot spots for the air pollutant emissions of the iron and steel industry. Our results suggest that the strengthened capacity policy and emission control policy were two major human driving forces of the emission mitigation of SO2 and PM for the Chinese iron and steel industry, with the latter playing a more important role during the period of 2010-2015.