Droplets can (for this discussion) be crudely divided in two large categories based on size
2 categories of droplets:
a) Droplets < 10 um: upper size limit of aerosol. Can float in the air/rooms by ventilation or winds and can be filtered (to 95%) by N95 favial masks (droplets < than 0.3 um). Here the surgical masks cannot help.
b) Droplets > 10 um (reaching 100+ um): called as spray droplets. Can be even visible by human from coughing/sneezing (0.1+ um).






