https://www.selleckchem.com/products/ot-82.html 5 in Baoding were ranked asExpressway less then Secondary roads less then Branch roads less then Major Roads. ③ Further study results of K2.5 characteristics demonstrated that the average K2.5 was higher than 0.15 g·VKT-1 (the value recommended by US EPA) in Baoding City, which would cause an underestimate of road dust emissions and increase the uncertainty of the emissions inventory if the recommended value from the EPA were adopted. The K2.5 in Baoding City is relatively high, indicating that the road dust contains a significant number of micro particles, increasing the contribution of road dust to urban atmospheric PM2.5.The atmosphere is a significant medium for the transportation and diffusion of volatile and semi-volatile pollutants. Furthermore, the atmosphere is the primary exposure route for pollutants to enter the human body. Therefore, the study of the environmental fate of pollutants in the atmosphere is essential. In this study, 16 polycyclic aromatic hydrocarbons (PAHs) were analyzed in snow samples and air samples within 24 hours after a snowfall, and the temporal trend of PAHs in the atmosphere was comprehensively studied. The results indicated that the detection rate of the 16 PAHs in snow was 100%, and the concentration of phenanthrene (538.3 ng·L-1) was the highest, followed by naphthalene (509.1 ng·L-1) and fluoranthene (429.9 ng·L-1), indicating that snowfall can remove PAHs from the atmosphere. After the snowfall, a falling-rising-falling temporal trend of the concentrations of PAHs in the atmosphere was observed. Higher concentrations appeared during rush hour, with the largest automobile exhaust emissions, while lower concentrations appeared during periods with the lowest human activity. The results indicated that the atmospheric concentrations of PAHs were predominantly influenced by human activities. Within 24 hours after snowfall, the ratio of PAHs between the gas phase and particle phase, wh