Temperature and humidity impact on droplet dynamics and aerosol virus spreading: Insights from multicomponent evaporation model

Droplets are critical vectors for transmitting respiratory diseases indoors. The dispersion and survival of droplets generated by human respiratory activities are closely related to their evaporation characteristics, which are strongly influenced by environmental factors such as temperature and relative humidity (RH). This study employs an optimized multicomponent evaporation model, incorporating both the Kelvin effect and the solute effect, to investigate droplet evaporation times and equilibrium diameters under varying indoor environmental conditions. The findings demonstrate that the improved model more accurately predicts evaporation time and droplet nuclei sizes in realistic indoor scenarios. High relative humidity and low indoor temperature conditions prolong droplet evaporation, potentially extending viral survival. For example, droplets initially sized at 50 exhibited larger normalized equilibrium diameters at 90% RH (0.44) compared to 50% RH (0.366), and smaller droplets had lower final normalized diameters ( ). Additionally, increased initial droplet velocity accelerated evaporation. Based on these results, practical recommendations are proposed: Firstly, virus survival conditions are optimal shortly after droplet emission, necessitating immediate preventive measures such as social distancing and proper mask usage. Secondly, maintaining indoor environments at moderately high temperatures and medium humidity levels accelerates droplet evaporation, reducing virus viability, and thus lowering the risk of disease transmission and human exposure.