AHR and inflammation: For a better understanding of the correlation between PM2.5 and airway inflammation, in this study, we aimed to evaluate the following hypotheses: (1) Exposure to PM2.5 from a traffic-related community would induce airway inflammation in normal healthy rats; (2) Inhaled PM2.5 may be involved in the pathogenesis of airway inflammatory disease through the AhR pathway; (3) BV may attenuate PM2.5-induced airway inflammation in rats by regulating immune disorders.