The study on free radical toxicological mechanism of aerosols

The coarse particulate samples (2 5?μm) and fine particulate samples(PM 2 5 ) were collected from one downtown area of Shanghai and one village place of suburb, by stacked filter air sampler. The element contents in aerosols and in their unsoluble parts were analyzed by PIXE. The free radical signals in particulates wrer detected by ESR. The cytotoxicity of UV radiated particulates was evaluated by MDA and MTT methods. The results show that the compouds of transition metals Cr, Mn, and Fe from downtown dissolve in water than those from suburb both in coarse and fine particulates and Fe compounds in fine particulates (PM 2 5 ) from suburb dissolve in water more easily than those in coarse particulates (2 5?μm). As soluble Fe compounds can induce OH free radicals by decomposition of H 2O 2, higher contents of soluble Fe and other transition elements in particulates would cause higher cytotoxicity. Furthermore, the free radical signal in particulates was observed by ESR,the cytotoxicity increased as they were irradiated by UV in these experiments. The results suggest that one of the main factors to cytotoxicity is free radicals.