General aerosol Sauter mean diameter measurement for spherical and non-spherical particles based on low-complexity scattering algorithm

Sauter mean diameter (SMD) is a key microphysical indicator in aerosol measurements that rely on opticalscattering-related methods. However, owing to the lacking clear definition of non-spherical SMD and the complexity of scattering calculations for non-spherical particles, existing SMD measurement methods are only applicable to spherical particles. A general SMD measurement method for both spherical and non-spherical aerosols is thus proposed. In this method, the shape coefficients of non-spherical particles are defined and used to calculate SMD. The scattering models for spherical and non-spherical particles are unified into a lowcomplexity scattering algorithm (LCSA). Based on LCSA, SMD can be measured using only two light sources of different wavelengths. Compared with SMD measurement results without considering particle shape, the accuracy of the proposed method increased by an average of 11.31% and 11.37% for unimodal and bimodal aerosols, respectively, while its accuracies for spherical and non-spherical aerosols respectively reached 95.26% and 93.43%.