Objective To observe the effects of atmospheric particulate matter (PM) exposure from two sources of motor vehicle exhaust (MVE) and biomass fuel (BMF) on the heart and lung tissues of rats. Methods Thirty rats were randomly divided into 3 groups, and they were exposed to clean air (control group), MVE (MVE group) and BMF (BMF group) for 12 weeks, respectively. The effect of long-term PM exposure on the morphological structure of heart and lung tissues was investigated by tissue and cell morphological observations, Masson staining, and immunohistochemistry. ResultsCompared with rats in the control group, the rats in the MVE group and the BMF group showed cellular degeneration, increased number of interstitial inflammatory cells, fibrous tissue proliferation, and cell apoptosis in the heart and lung tissues of the PM-exposed rats. ConclusionExposure to air pollution particulate matter for 12 weeks can significantly cause inflammatory and damage to the heart and lung tissues of rats.