A　comprehensive　ammonia　(NH3)　emission　inventory　for　the　Beijing-Tianjin-Hebei　(BTH)　region　was　developed　based　on　the　updated　source-specific　emission　factors　(EFs)　and　the　county-level　activity　data　obtained　from　a　full-coverage　investigation　launched　in　the　BTH　region　for　the　first　time.　The　NH3　emission　inventory　within　1　km　x　1　km　grid　was　generated　using　source-based　spatial　surrogates　with　geographical　information　system　(GIS)　technology.　The　total　NH3　emission　was　1573.7　Gg　for　the　year　＇　2010.　The　contributions　from　livestock,　farmland,　human,　biomass　burning,　chemical　industry,　fuel　combustion,　waste　disposal　and　on-road　mobile　source　were　approximately　56.6%,　28.6%,　7.2%,　3.4%,　1.1%,　1.3%,　1.0%　and　0.8%,　respectively.　Among　different　cities,　Shijiazhang,　Handan,　Xingtai,　Tangshan　and　Cangzhou　had　higher　NH3　emissions.　Statistical　analysis　aiming　at　county-level　emission　of　180　counties　in　BTH　indicated　that　the　NH3　emission　in　most　of　the　counties　were　less　than　16　Gg.　The　maximum　value　of　the　county　level　emission　was　approximately　25.5　Gg.　Higher　NH3　emission　was　concentrated　in　the　areas　with　more　rural　and　agricultural　activity.　Monthly,　higher　NH3　emission　occurred　during　the　period　from　April　to　September,　which　could　be　attributed　to　the　temperature　and　timing　of　planting　practice.　The　validity　of　the　estimated　emissions　were　further　evaluated　from　multiple　perspectives　covering　(1)　uncertainty　analysis　based　on　Monte　Carlo　simulation,　(2)　comparison　with　other　studies,　(3)　quantitative　analysis　of　improvement　in　spatial　resolution　of　activity　data,　and　(4)　verification　based　on　a　comparison　of　the　simulated　and　observed　surface　concentrations　of　ammonium.　The　detailed　and　validated　ammonia　emission　inventory　could　provide　valuable　information　for　understanding　air　pollution　formation　mechanisms　and　help　guide　decision-making　with　respect　to　control　strategies.　(C)　2015　Elsevier　Ltd.　All　rights　reserved.