Carl Flügge presented the concept of “droplet transmission” in 1897 after showing pathogens in expiratory droplets settle around an infected individual. In the 1930s, after William F. Wells investigated TB transmission, the understanding of respiratory droplet emissions evolved to include “large” and “small” droplets. Wells noted that large droplets settle faster than they evaporate, whereas small droplets evaporate faster than they have time to settle. When the small droplets move from warm and moist air within the human body to the colder and drier air, they form residual particulate matter that is referred to as droplet nuclei/ aerosols. The WHO and CDC use this dichotomous classification to employ diameter cutoffs from 5-10 μm to classify droplets as either droplets or aerosols. The authors argue that arbitrary droplet size cutoffs oversimplify the complexity of respiratory transmission.