Objectives: Traffic-related particulate matter (PM) is one of the major sources of air pollution in metropolitan areas. This study is to observe the interactive effects of gene and fine particles (particles smaller than 2.5 μm – PM_2.5) on the respiratory system and explore the mechanisms linking PM_2.5 and pulmonary injury. Material and Methods: The participants include 110 traffic policemen and 101 common populations in Shanghai, China. Continuous 24 h individual-level PM_2.5 is detected and the pulmonary function, high-sensitivity C-reactive protein (hs-CRP), Clara cell protein 16 (CC16) and the polymorphism in CXCL3, NME7 and C5 genes are determined. The multiple linear regression method is used to analyze the association between PM_2.5 and health effects. Meanwhile, the interactive effects of gene and PM_2.5 on lung function are analyzed. Results: The individual PM_2.5 exposure for traffic policemen was higher than that in the common population whereas the forced expiratory volume in 1 s (FEV₁), the ratio of FEV₁ to forced vital capacity (FEV₁/FVC) and lymphocytes are lower. In contrast, the hs-CRP level is higher. In the adjusted analysis, PM_2.5 exposure was associated with the decrease in lymphocytes and the increase in hs-CRP. The allele frequencies for NME7 and C5 have significant differences between FEV₁/FVC ≤ 70% and FEV₁/FVC > 70% participants. The results didn’t find the interaction effects of gene and PM_2.5 on FEV₁/FVC in all the 3 genes. Conclusions: The results indicated that traffic exposure to high levels of PM_2.5 was associated with systemic inflammatory response and respiratory injury. Traffic policemen represent a high risk group suffering from the respiratory injury.