“…The D 2 -law, proposed in the seminal works of Langmuir 8 and others, 9,10 states that the surface of an evaporating droplet decreases linearly with time, at a rate fixed by the ambient properties. Although deviations from the classical D 2 -law have been observed in some peculiar conditions, e.g., for droplet sizes of the order of the mean vapor's free path, 11 trans-critical evaporation of nano/micro-droplets 12 and multi-component droplets, 13,14 a linear decrease in the droplet surface is usually observed for single-component micro/millimetric droplets. Nonetheless, recent studies on respiratory events 3,4 found that droplet lifetime may increase even 150 times as compared to Wells's estimate; although a linear decrease in the droplet surface could still be observed, the evaporation rate is found to be much lower than that predicted by the D 2 -law.…”