Abstract:  Based on the observational data with CE-318 sun photometer in Anshan atmospheric composition monitoring station from September to November 2010, the atmospheric aerosol optical depth (AOD) and Angstrom exponent and so on were calculated according to the principles of AOD measurements. The optical feature of aerosol was analyzed in Anshan. The results indicate that AOD value increases with the decrease of wavelength. The mean maximum AOD value occurs in September, then in October, and the minimum one is in November. For the frequency distributions, the mean diurnal AOD values concentrate from 0.4 to 0.6 in September 2010 and from 0.0 to 0.4 in October and November 2010, respectively.  These results suggest that the air is clean from October to November. According to the frequency distributions of Angstrom exponent, atmospheric pollutant is dominated by fine particles in autumn in Anshan. There is a logarithmic relationship between the AOD (500 nm) values  and wavelength exponent, and both correlation coefficients are 0.5145, 0.8412 and 0.2715 in September, October and November, respectively. AOD value is a negative correlation with concentrations of PM₁₀, PM_2.5, PM_1.0 in September, while it is a positive correlation in October and November. The correlation between AOD value and fine particle of aerosol is significant in October and November. There is a less negative correlation between AOD value and visibility, and it suggests that aerosol particles in upper level have a major impact on aerosol optical depth.

Key words: Aerosol optical depth, Angstrom exponent, PM₁₀, PM_2.5, PM_1.0, Visibility