Estimation of the concentration and chemical composition of kosa aerosols at their origin

Kosa aerosols are formed of mineral dust lifted into the atmosphere by dust storms generated over the Asian continent. An intense dust storm which lifted kosa particles into the atmosphere was generated over the Badain Jaran Desert, China from 14 to 15 April 1998. We sampled the kosa aerosol at seven locations in China and Japan along its transport route, and investigated aerosol mass concentrations and the concentrations of chemical components in the aerosol. The aerosol mass concentrations and concentrations of crustal elements in the aerosols decreased exponentially with the distance from the kosa aerosol source. The chemical composition of the kosa aerosol at source, estimated from regressions of aerosol crustal element concentrations on distance from the kosa source, closely coincided with those of simulated Asian mineral dust certified reference material (CJ-2) prepared from the desert surface soil. The estimated concentration of Al in the kosa source aerosol was 5.3×103 μg m−3 and the aerosol mass concentration was 9.0×104 μg m−3.