Abstract: The features of BC aerosol over Urumqi in winter were analyzed based on the related black carbon aerosol, concentration of air pollutants and　meteorological data collected at Urumqi Atmospheric Environment Monitoring Station. The results showed that the average daily BC concentration was 6.55 μg/m³, the daily variation was significant, and there were the good correlations between the average daily BC concentration and API,PM₁₀, PM_2.5and _^NOx. The hourly variation of BC was significantly bimodal, which was related to the direct emissions from motor vehicles, human activities and heating with coal. The frequency of BC concentration occurred mainly in a range of 2-9 μg/m³, and its proportion was as high as 60% of all the observed values. Compared with other results, the BC level over Urumqi was higher than that in some foreign cities but relatively lower than that in most domestic cities. High BC pollution was mainly caused by air mass from the north and northwest. BC concentration began to decrease when wind speed was higher than 1.0 m/s, and the decrease could be close to 50%. There was no significant correlation between wind speed and BC concentration when wind speed was higher than 2.0 m/s. BC concentration in weekdays was higher than that in weekends.

Key words: winter, air pollution, black carbon, aerosol, Urumqi