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Secondary inorganic aerosols (SIA) account for 20-60% of the total fine particulates in the Beijing-Tianjin-Hebei (BTH) region of China, indicating an urgent need to clarify the relationship among such compounds. The purpose of this study was to quantify the relationship between emissions of NH 3 , NOx, SO 2 , VOCs and SIA concentrations during a severe winter haze episode using an air quality model and a meteorology-based redistributed NH 3 emission inventory within the BTH region. The results showed that the model performance regarding the NH 3 simulations in January by the four emission inventories improved after the redistribution of daily NH 3 emissions, with an increase of 0.02-0.13 in R, a 9-56% decrease in NMB, and a 7-51% decrease in NME. The updated simulations reproduced the daily observations of SIA, SO 2 , and NO 2 well. A total of 125 sets of sensitivity simulations showed that a synergistic reduction in NH 3 and VOCs was more efficient in terms of SIA control than simply reducing SO 2 or NOx in the BTH region. If only NOx emissions were reduced, the SIA concentration would first increase and then decrease, and it could decline by another 0.86-8.03% in parallel with an equal NH 3 emission cut. SIA could be reduced by approximately 22.68% with the most stringent inorganic precursors' control. Moreover, VOCs emission reductions could lead to a decrease in SIA, and the impact of VOCs on SIA was similar to that of NH 3 . The collaborative control of both inorganic precursors and VOCs was more effective than single-factor control measures for decreasing SIA, and the decline rate was approximately 29.26% under minimum emission conditions. This improved effectiveness was obtained because VOCs mitigation effectively decreases the ozone concentration, which in turn influences SIA formation. Finally, on the premise of a 60% SO 2 cut, the reduction scheme NH 3 :VOCs:NOx = 4:4:1 was suggested for SIA control., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)