Summer-winter differences of PM2.5 toxicity to human alveolar epithelial cells (A549) and the roles of transition metals.

Atmospheric fine particulate matters (PM2.5) induce adverse human health effects through inhalation, and the harmful effects of PM2.5 are determined not only by its air concentrations, but also by the particle components varied temporally. To investigate seasonal differences of the aerosol toxicity effects including cell viability and membrane damage, cell oxidative stress and responses of inflammatory cytokines, the human lung epithelial cells (A549) were exposed to PM2.5 samples collected in both summer and winter by the in vitro toxicity bioassays. Toxicological results showed that, the PM2.5 led to the cell viability decrease, cell membrane injury, oxidative stress level increase and inflammatory responses in a dose-dependent manner. Temporally, the cytotoxicity of winter PM2.5 was higher than summer of this studied industrial area of Nanjing, China. According to the different contents of heavy metals accumulated in PM2.5, the transition metals such as Cu might be an important contributor to the aerosol cell toxicity.