The aerosols in atmosphere are often random cluster of small primary particles with disordered appearance. They are considered to be fractal aggregates with a noninteger dimensions and have the important property of invariance under scale transformation. The essential fractal morphology are included in this study of scattering properties for aggregated aerosol particles. The fractal aggregates are simulated by using the growth model of hierarchical cluster-cluster aggregation. The T-matrix approach together with the translation addition theorem for vector spherical waves is employed to solve the aggregate scattering problem. Numerical results for scattering cross sections are illustrated for fractal clusters.