Source Apportionment of Black Carbon Aerosol in the North Suburb of Nanjing

: Based on one year real-time measurements from a seven-wavelength Aethalometer combined with an Aethalometer model, the measured aerosol absorption coefficients at different wavelengths have been used to apportion the contribution of fossil fuel and biomass burning sources to the total black carbon (BC) mass concentration in the north suburb of Nanjing. Good consistency in the relationship between the Angstrom absorption exponent(α)and the ratio of BC from biomass burning sources to total BC (BB) was obtained during this period. The α was highest in winter and lowest in summer, which indicates the change in the source of the absorbing aerosols and their relative source strength. The BC and the BC from fossil fuel (BCff) and biomass burning (BCbb) mass concentrations exhibit significant diurnal variation, with higher values during 07:00 to 09:00 (local time) and 18:00 to 21:00. The BCff was three to five times higher than the BCbb and contributes greatest to the BC mass concentrations throughout the day. Night time BC values were about a factor of 1.2 higher than day time BC values. Meanwhile, the concentration weighted trajectory (CWT) analysis indicates that the highest value of BC was concentrated in the Zhejiang, Anhui, Jiangxi, and Fujian provinces.