Objective:　The　development　of　nanotechnology　has　spurred　concerns　about　the　health　effects　of　exposure　to　nanoparticles　(NPs)　and　ultrafine　particles　(UFPs).　Toxicological　data　on　NPs　and　UFPs　may　provide　evidence　to　support　the　development　of　regulations　to　reduce　the　risk　of　particle　exposure.　We　tried　to　provide　fundamental　data　to　determine　differences　in　cytotoxicity　induced　by　ambient　UFPs　and　engineered　metal　oxide　NPs　(ZnO,　NiO,　and　CeO2).　Methods:　UFPs　were　sampled　by　using　of　a　nano　micro-orifice　uniform　deposit　impactor.　Physicochemical　characterization　of　the　UFPs　and　nano　metal　oxide　particles　were　studied　by　scanning　electron　microscopy　and　transmission　electron　microscopy.　Cellular　toxicity　induced　by　the　different　particles　was　assessed　by　using　of　comprehensive　approaches　and　compared　after　A549　cells　were　exposured　to　the　particles.　Results:　All　of　the　measured　particles　could　damage　A549　cells　at　concentrations　ranging　from　25　to　200　mu　g/mL.　The　lowest　survival　ratio　and　the　highest　lactate　dehydrogenase　level　were　caused　by　nano-ZnO　particles,　but　the　highest　levels　of　intracellular　reactive　oxygen　species　(ROS)　and　percentages　of　apoptosis　were　observed　in　cells　treated　with　the　soluble　fraction　of　ambient　fine　particles　(PM1.8)　at　200　mu　g/mL.　Relatively　high　concentrations　of　anthropogenic　metals,　including　Zn,　Ni,　Fe,　and　Cu,　may　be　responsible　for　the　higher　toxicity　of　fine　ambient　particles　compared　with　the　ambient　coarse　particles　and　UFPs.　The　selected　heavy　metals　(Zn,　Ni,　Fe,　and　Cu)　were　found　to　be　located　in　the　perinuclear　and　cytoplasmic　areas　of　A549　cells.　The　distribution　pattern　of　metals　from　ambient　particles　showed　that　distributions　of　the　metals　in　A549　cells　were　not　uniform　and　followed　the　pattern　Cu　＞　Zn　＞　Fe　＞　Ni,　suggesting　that　Cu　was　absorbed　by　A549　cells　more　easily　than　the　other　metals.　Conclusions:　Metal　nanoparticles　oxides　and　UFPs　at　low　concentration　could　damage　to　cells,　but　the　manufactured　metal　oxide　nanoparticles　are　not　highly　toxic　to　lung　cells　compared　to　environmental　particles.　The　local　concentration　effect　of　heavy　metals　in　A549　cells,　as　well　as　the　induction　of　oxidative　stress　by　the　particles,　may　be　responsible　for　the　damage　observed　to　the　cells.