Study of the toxicological mechanism of acidified aerosols

More than 30 aerosol samples were collected from 1 place near Zaojiaban Road (downtown of Shanghai) and 1 village near Jiading country (suburb) by a stacked-filter air sampler. The coarse particulates (>2.5 microm) and the fine particulates (PM2.5) and their unsoluble parts were analyzed by proton-induced X-ray emission. The cytotoxicity of particulates from the two places was evaluated by malondialdehyde (MDA) and thiazolyl blue (MTT) methods. The results show that the transition metal Fe, Cr, and Mn compounds from downtown are more easily soluble than those from the suburb, both in coarse and fine particulates, and the S content is much higher in particulates from downtown than that from the suburb. The cytotoxicity of the particulates from downtown is higher than that from the suburb and the cytotoxicity of acidified particulates is significantly higher than that of the controls. Because there are higher-soluble transition metal compounds that can induce free radicals in acidified particulates, the soluble transition metals may be one of the main factors for cytotoxicity.