The optical properties of aerosol clusters containing dust and microplastics

Abstract The unique optical properties of microplastic particles have a significant impact on atmospheric radiative forcing. Based on the generalized multi-particle Mie theory, this paper presents a comparative study of the extinction properties and absorption properties of single-component and mixed aerosol clusters composed of microplastics, dust, and black carbon in different structural forms and particle sizes. The results show that the structure, particle size, mixing arrangement, and orientation of aerosol particles containing microplastics will directly affect their optical properties. As the incident wavelength increases, significant differences are observed in the extinction and absorption cross-sections of microplastic and dust particle chains with different structures, although they exhibit similar trends. However, black carbon particle chains show a distinct variation pattern. In the mixed particle chains with different particle sizes, as the incident wavelength increases, the extinction and absorption cross-sections are significantly larger than those of the particle chains with the same particle size, indicating that the particle size has a remarkable influence on their optical properties. The different mixing forms and orientations of aerosol clusters also significantly affect their extinction and absorption cross-sections. These findings provide a new theoretical perspective for environmental optics and remote sensing monitoring of aerosols.