A　campaign　of　sampling　total　suspended　particles　(TSP)　and　fine　particles　(PM2.5)　in　Beijing　from　2001　to　2004　were　carried　out　to　investigate　the　mineral　aerosol　and　its　impact　on　urban　pollution　aerosols,　mainly　sulfate,　nitrate,　and　ammonium.　In　urban　Beijing,　mineral　aerosol　accounted　for　32-67%　of　TSP,　10-70%　of　PM2.5　in　normal　four　seasons,　and　as　high　as　74%　of　TSP　and　90%　of　PM2.5　in　dust　storm　period.　The　sources　from　outside　Beijing　accounted　for　62%　of　the　total　mineral　aerosols　in　TSP,　and　76%　in　PM2.5　in　spring,　69%　and　45%　in　TSP　and　PM2.5,　respectively,　in　winter,　similar　to　20%　of　both　TSP　and　PM2.5　in　summer　and　autumn;　and　it　reached　as　high　as　97%　of　TSP　in　dust　storm　days.　Mineral　aerosol　has　an　important　positive　influence　on　formations　of　sulfate,　nitrate,　and　ammonium,　as　there　was　a　positive　correlation　between　sulfate/nitrate/ammonium　and　mineral　aerosol　under　appropriate　meteorological　conditions.　Sulfate,　and　ammonium　mainly　existed　in　fine　particles,　PM2.5,　Sulfate　might　mostly　derive　from　the　formation　on　the　pathways　of　the　long-range　transport　by　the　reactions　of　their　precursors　SO2　on　the　surfaces　of　dust　particles,　while　nitrate　was　mostly　derived　by　the　homogeneous　reaction　and　the　neutralization　of　their　precursors　NO2　on　surfaces　of　mineral　aerosol.　Nitrate　and　ammonium　mostly　derived　from　the　local　pollution　sources.　(C)　2007　Elsevier　Ltd.　All　rights　reserved.