PM10 in a background urban site: Chemicalcharacteristics and biological effects.

PM10 was sampled in a background urban site in Torino, a northern Italian city. PM10 extracts were tested with THP-1 and A-549 cells to evaluate their effects on cell proliferation, LDHactivity, TNF, IL8 and CYP1A1 expression, and genotoxic damage induction (Comet assay).Through Principal Component Analysis (PCA), it was observed that (1) the aqueous extractsinduced the inhibition of cell proliferation in the warm season that clustered together tototal ions, (2) organic extracts determined a winter cell viability reduction and (3) there wasa genotoxic effect associated with PAH and metal concentrations. The analysed low PAHlevels were unable to induce significant CYP1A1 expression. The results obtained confirmedthat PM composition and seasonality play an important role in particle-induced toxicity. Thepresence of PM10-induced biological effects at a low polluted site suggested that a reductionof PM10mass did not seem to be sufficient to reduce its toxicity.