Abstract: This article aims to observe and analyze the morphology and element composition of the leaf surface sediments beside urban roads, to obtain the main particle composition of air pollution in different areas of the city, to determine the element content in the sediments, and then to infer the source of pollution. In summer (July) and winter (January), leaves were collected from residential area (Yanggongqiao), commercial area (Guanyinqiao) and park area (Zhaomushan Mountain Park) respectively, and the morphology and element composition of leaf surface sediment were analyzed by the scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). The results showed that the particles on the surface of leaves in summer were less than those in winter, and the particles near the park were less than those in the other two areas. There were more PM10 particles in residential areas and more PM2.5 particles in commercial areas. The main components of particles were carbon, oxygen, silicon, potassium, calcium, magnesium, aluminum, iron, phosphorus, sulfur etc. The air quality of Chongqing main city is good, and the air quality is better in summer than in winter as well as better in the park area than in the other two areas. The main sources of airborne particulates are soil dust, automobile exhaust and construction dust. Construction dust pollution in residential areas is higher than that in the other two areas, and automobile exhaust pollution in commercial areas is higher than that in the other two areas. The application of lead-free gasoline has made the lead content in urban air particulates lower than the detectable value of the spectrometer. The application of unleaded gasoline makes the lead content in urban air particulate matter lower than the value that can be detected by energy spectrometer.