In　this　paper,　an　integrated　MM5-CMAQ　modeling　approach　was　employed　to　investigate　the　PM10　air　Pollution　issue　in　Beijing,　China,　with　a　focus　on　assessing　pollution　contributions　from　surrounding　provinces.　A　2-level-nested　grid　domain　with　spatial　resolutions　of　36　and　12　km　was　designed　for　the　study　region.　Seven　monitoring　stations　across　Beijing　municipality　were　selected　to　provide　hourly　PM10　measurement　data.　The　months　of　January,　April,　July　and　October　in　2002　were　taken　as　target　periods　for　model　performance　evaluation.　Five　emission　scenarios　were　designed　and　run　in　order　to　quantitatively　assess　the　trans-boundary　P-10　contributions.　The　results　show　that,　while　Beijing　needs　to　take　positive　steps　to　reduce　its　own　pollution　emissions,　much　effort　should　also　be　placed　on　demanding　more　pollution　reduction　and　better　environmental　performance　from　surrounding　provinces.　(c)　2006　Elsevier　Ltd.　All　rights　reserved.