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　NH3,　NOx,　SO2,　VOCs　and　SIA　concentrations　during　a　severe　winter　haze　episode　using　an　air　quality　model　and　a　meteorology-based　redistributed　NH3　emission　inventory　within　the　BTH　region.　The　results　showed　that　the　model　performance　regarding　the　NH3　simulations　in　January　by　the　four　emission　inventories　improved　after　the　redistribution　of　daily　NH3　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,　SO2,　and　NO2　well.　A　total　of　125　sets　of　sensitivity　simulations　showed　that　a　synergistic　reduction　in　NH3　and　VOCs　was　more　efficient　in　terms　of　SIA　control　than　simply　reducing　SO2　or　NOx　in　the　Bill　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　NH3　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　NH3.　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%　SO2　cut,　the　reduction　scheme　NH3:VOCs:NOx　=　4:4:1　was　suggested　for　SIA　control.