unassigned: This study was to explore the toxicological mechanisms by which PM2.5 causes lung dysfunction. unassigned: The expression of circ_0038467 and miR-138-1-3p in PM2.5-induced human bronchial epithelial cell line BEAS-2B was detected by RT-qPCR. The effects of circ_0038467 and miR-138-1-3p on proliferation, apoptosis, and inflammatory cytokines (IL-6 and IL-8) in PM2.5-induced BEAS-2B were determined using cell counting kit-8, flow cytometry, western blot, and enzyme-linked immunosorbent assay, respectively. The levels of nuclear factor kappa B (NF-κB) pathway-related protein were also analyzed by western blot. The binding interaction between circ_0038467 and miR-138-1-3p was confirmed by dual-luciferase reporter assay and RNA immunoprecipitation assay and pull-down assay. unassigned: circ_0038467 expression was increased by PM2.5 treatment in BEAS-2B cells in time- and dose-dependent methods, and knockdown of circ_0038467 reversed PM2.5-triggered BEAS-2B cell death and inflammatory response. miR-138-1-3p was decreased by PM2.5 treatment, and restoration of miR-138-1-3p attenuated PM2.5-induced BEAS-2B cell injury. In a mechanical study, we found circ_0038467 directly bound to miR-138-1-3p, and further rescue experiments exhibited miR-138-1-3p inhibition partially overturned the regulatory functions of circ_0038467 knockdown in PM2.5-induced BEAS-2B cells. unassigned: circ_0038467 provided a potential therapeutic strategy for future clinic intervention in air pollution-triggered lung dysfunction.