This　study　investigates　the　gas　sensing　properties　of　Pt-modified　ZrS2　monolayers　for　seven　harmful　environmental　gases　(CO,　H2S,　NH3,　NO,　NO2,　SO2,　and　SO3)　using　density　functional　theory　(DFT).　The　adsorption　structures,　charge　transfer,　band　structures,　density　of　states,　sensitivity,　and　recovery　times　are　systematically　analyzed.　The　results　reveal　that　Pt　modification　significantly　enhances　the　gas　adsorption　capability　of　ZrS2,　leading　to　notable　changes　in　its　electronic　properties.　For　Pt@ZrS2,　the　adsorption　of　gases　such　as　CO,　H2S,　NH3,　NO,　SO2,　and　SO3　increases　the　band　gap,　which　reduces　conductivity,　whereas　NO2　causes　a　decrease　in　the　band　gap,　enhancing　conductivity.　In　contrast,　Pt-doped　ZrS2　shows　a　reduction　in　the　band　gap　upon　adsorption　of　most　gases,　except　for　SO2,　which　increases　the　band　gap.　Sensitivity　calculations　indicate　that　Pt@ZrS2　exhibits　the　highest　sensitivity　to　CO　and　SO2,　with　values　of　156.72　and　33.56,　respectively,　at　room　temperature.　Recovery　time　analysis　demonstrates　that　Pt@ZrS2　is　suitable　for　real-time　monitoring　of　SO2,　while　Pt-doped　ZrS2　is　ideal　for　real-time　monitoring　of　CO　and　H2S.　These　findings　suggest　that　Pt-modified　ZrS2　monolayers　have　great　potential　for　selective　detection　and　real-time　monitoring　of　harmful　gases,　making　them　promising　candidates　for　environmental　sensing　applications.