The　re-suspended　road　dust　samples　from　53　sites　that　could　cover　basically　the　entire　Beijing　in　summer,　and　aerosol　samples　from　three　representative　sites　in　Beijing　in　four　seasons　were　collected　to　study　concentrations　and　spatial　variations　of　elements　and　ions　in　resuspended　road　dust　and　its　contribution　to　the　air-borne　particulate　pollution.　Ca,　S,　Cu,　Zn,　Ni,　Pb　and　Cd　were　main　pollution　elements,　and　Ca2+,　SO4(2-),　Cl-,　K+,　Na+　and　NO3-　were　major　ions　in　re-suspended　road　dust.　Al,　Ti,　Sc,　Co　and　Mg　in　re-suspended　road　dust　were　mainly　originated　from　crustal　source,　while　Cu,　Zn,　Ni　and　Pb　were　mainly　originated　from　traffic　emissions　and　coal　burning,　and　Fe,　Mn　and　Cd　were　mainly　from　industrial　emissions　and　coal　combustion.　Ca2+　and　SO4(2-)　mainly　came　from　construction　activities,　construction　materials　and　secondary　gas-particle　conversions,　Cl-　and　Na+　were　derived　from　industrial　wastewater　disposal　and　chemical　industrial　emissions,　and　NO3-　and　K+　were　from　vehicle　emissions,　photochemical　reactions　of　NO,,　biomass　and　vegetable　burning.　The　contribution　of　mineral　aerosol　from　inside　Beijing　to　the　total　mineral　aerosols　was　30%　in　spring　of　2002,　70%　in　summer　of　2002,　80%　in　autumn　of　2003,　20%　in　winter　of　2002.　The　pollution　levels　of　some　major　pollution　species,　Ca,　S,　Cu,　Zn,　Ni,　Pb,　Fe,　Mn,　and　Cd　in　resuspended　road　dust　reached　76%,　87%,　75%,　80%,　82%,　90%,　45%,　51%,　and　94%,　respectively,　and　their　contributions　to　the　related　elements　in　PM10　were　20%-45%,　5%-18%,　4%-50%,　2%-46%,　4%-52%,　5%-20%,　30%-60%,　20%-40%　and　2%-25%.　Re-suspended　road　dust　from　the　traffic　and　construction　activities　is　one　of　the　major　sources　of　the　air-born　particulate　pollution　in　Beijing.