The results of calculations of the time-dependences of the radius and temperature of a carbon aerosol particle during its combustion in the radiation field of a powerful laser in wet air are presented. The combustion is shown to take place more rapidly than in dry air. The process of particle combustion was also observed experimentally. Qualitative agreement with the calculations was obtained. A distinct thermal halo around the particle due to the combustion of hydrogen formed in the reaction of carbon with water vapor was detected.