Abstract:The effects of traffic emission and heating in winter on the components of atmospheric aerosol were revealed by using the relation between the properties of aerosol and the aerosol absorption ngstrom exponent (AAE) as the indicator for the aerosol’s composition, based on a 37 d measurement campaign from 13 November to 19 December 2009 with the Aethalometer in the region of Beijing. The diurnal variation characteristics and the comparison analysis were studied on the 37 d average, clean, and fog haze conditions. The results showed that the AAE reached the minimum during traffic rush hours and increased at other times in the average and fog haze conditions. In clean condition, the AAE decreased gradually from nighttime to daytime, and an inflexion would turn with the advent of the traffic rush hours. The AAE was significantly higher in clean condition than in the two other conditions, and the difference became more significant at night. Combining the varied weather conditions, the paper demonstrated that significant emi ssions of brown carbon containing aerosols in the region of Beijing in winter, especially during the night, and emissions of the fine particles during traffic rush hours, as well as the important impact on the components of aerosol in ambient atmosphere.