In this study, a cluster-cluster aggregation (CCA) model was used to form 4-sphere and 16-sphere aerosol aggregate models for different numbers of soot aerosol particles. By combining the hygroscopic nature of individual aerosol particles and the fractal theory of aerosol aggregates, a model for aerosol aggregates covering a water layer was generated. The scattering characteristics of soot in the coating layer were simulated and analyzed using the discrete dipole approximation (DDA). Simulation results show that an increase in relative humidity has the greatest influence on the extinction, scattering, and absorption of aerosol aggregates with a rotation radius ≤40 nm. Furthermore, the influence of aerosol aggregates and relative humidity on the UV pulse response and path loss was analyzed using a single-scattering pulse response model. The simulation results show that the effects of aerosol aggregates and relative humidity on UV communication are concentrated on monomer particles with smaller radii (r₀≤40 nm). When the radius of the monomer particles is fixed, if the number of particles forming a cluster or the relative humidity of the aerosol aggregates increases, the pulse response is larger, the path loss is smaller, and the signal at the UV receiver is better.