Real-time dynamic measurement of scattering characteristics of optically-levitated fly ash interacting with water-soluble ammonium sulfate aerosol

This paper proposes a coupled laser levitation and scattering measuring system to realize real-time dynamic measurement of scattering characteristics of individual fly ash particles interacting with water-soluble ammonium sulfate aerosols of different concentrations. The scattering coefficients, absorption coefficients, and phase functions of aerosols were calculated. The disparities in scattering characteristics interacting fly ash with ammonium sulfate, and the impact of typical influencing parameters on the scattering characteristics were discussed in detail. The findings highlighted that the scattering characteristics of aerosols followed with those of Mie particles, with an increase in the particle size leading to an enhancement in the forward scattering intensity. Notably, dynamic measurement demonstrated that the scattering intensity with high ammonium sulfate concentrations (>= 1 mol/L) showed an upward trend, exerting a more pronounced impact than low-concentration counterparts. Furthermore, the particle size has a stronger effect on the scattering characteristics than the complex refractive index induced by varying concentrations.