Using a new aerosol relative optical thickness concept to identify aerosol particle species

• Developed a new concept, AROT, using a multi-log-normal distribution model
• Found aerosol particles in Beijing are a mixture of dust and soot in the winter.
• Analyzed aerosol particle species present in the atmospheres of three cities

We developed an aerosol relative optical thickness concept and then established an effective aerosol particle recognition model by analyzing variations in aerosol optical thicknesses in Beijing between 2001 and 2006. The accuracy of the model was verified using inverse calculations. The aerosol particle types and size distributions were assessed for several typical atmospheric phenomena, and the characteristic relative optical thicknesses for several typical aerosols were identified. Finally, we analyzed annual variations in the aerosol particle species in several eastern Asian cities using the model.