Abstract: Objective To study the effects of PM_2.5 collected in duststorm and normal weather days on the secretion of interleukin-8(IL-8)and tumor necrosis facto-rA(TNF-α)human lung adenocarcinoma A549 cells(A 549 cells).Methods PM_2.5 was collected during duststorm and normal weather days in Wuwei,a city of Gansu province.A549 cells were exposed to PM_2.5 at the doses of 25,50,100,200 μg/ml,respectively.After 24 hours,cytotoxicity of the PM_2.5 was measured by cell number counting.The levels of IL-8 and TNF-α were measured using radio-immunity assay.Results PM_2.5 collected in duststorm increased the proliferation of A549 cells at low doses while inhibited it athigh doses.PM_2.5 collected in duststorm and normal weather days,however,inhibited at the tested concentrations.Both kind of PM_2.5 increased the secretion of IL-8.However,there were no significant changes in the secretion of TNF-α from cells treated by both kind of PM_2.5.Conclusion PM_2.5 from the sandstorm dust and non-sandstorm dust could induce the early inflammatory reaction in the A 549 cells.