On the basis of a solution of the integrodifferential equation for radiation transport, a study is made of the effect of aerosol on the formation of outgoing thermal radiation in the 400-2685 cm** minus **1 range for aerosol models of various shapes. It is shown that the effect of the aerosol on the brightness temperature of radiation can amount to 0. 1-0. 4 K for a pure atmosphere and to 2-4 K for a turbid atmosphere. The contribution of aerosol scattering to the formation of outgoing thermal radiation can amount to 5-10%. An approximate method of taking the effect of aerosol into account is proposed.