Winter is a peak season for respiratory disease outbreaks, with indoor environments being major sites of airborne transmission. Radiant floor heating, widely applied in cold regions for its energy efficiency and thermal comfort, can strongly affect indoor aerosol transport. Therefore, a numerical simulation was conducted to investigate the effects of radiant floor heating and body thermal plumes on sneeze droplet dispersion in a typical indoor environment. The results showed that body thermal plumes delayed aerosol deposition and increased concentrations in the breathing zone. When radiant floor heating was operating, aerosols travelled farther and reached substantially higher concentrations. As the floor temperature (Tf) rose to 30–32°C, radiant floor heating became the dominant factor governing aerosol dispersion, weakening the influence of body plumes. In the breathing zone, the average aerosol concentrations were 7.26 μg/m3 and 8.50 μg/m3 at Tf = 26°C and 28°C, increasing to 17.25 μg/m3 and 42.36 μg/m3 at Tf = 30°C and 32°C, respectively, compared with 13.70 μg/m3 under the sole effect of body thermal plumes. The results suggest that maintaining a mild floor temperature of 26°C could reduce aerosol concentrations in the breathing zone while ensuring thermal comfort and conserving energy.
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