In conclusion, our results strongly suggest that repeated exposure to PM2.5 induces epigenetic silencing of P53 through ROS-Akt-DNMT3B pathway-mediated promoter hypermethylation, which not only provides a possible explanation for PM-induced lung cancer, but also may help to identify specific interventions to prevent PM-induced lung carcinogenesis. This evidence concerns the gene DNMT3B and lung carcinoma.