A method for estimating mineral dust concentration in aerosol mixture using a polarization lidar

摘要

A method using the lidar depolarization ratio for estimating mineral dust concentration in aerosol mixture is described. The method is based on a simple assumption of an external mixture of two types of aerosols with different aerosol depolarization ratio. The method was applied to the lidar data observed in Beijing to estimate contribution of Asian dust in extinction coefficient profiles. The results showed the method is useful for separating contributions of Asian dust and air pollution aerosols. Further conversion to estimate dust mass concentration was tested. The mass/extinction conversion factor determined by the comparison with a high-volume sampler data was 1870 (/spl mu/g/m/sup 3/)/(km) for typical Asian dust in Beijing. The conversion factor is dependent on the particle size distribution and is much smaller for air pollution aerosols.