Microbiology
Both large droplets and droplet nuclei have identical size, travel distances, and infection-control requirements; the only difference is the pathogen type within them determines their behavior rather than size or physics.
Large droplets are microscopic and remain suspended for hours in calm air, making hand hygiene ineffective, while droplet nuclei are large and settle quickly so masks are unnecessary but surface cleaning is essential.
Large droplets are produced only during coughing and cannot be generated by talking, while droplet nuclei only originate from nonrespiratory sources like toilets and cannot be controlled by ventilation strategies in occupied spaces, so disinfection of surfaces is the main approach for both.
Large droplets are relatively big (> ~5 μm), fall quickly and require close proximity for transmission, so surgical masks and distancing reduce risk; droplet nuclei are tiny (< ~5 μm), remain airborne longer, can travel farther, and require airborne precautions such as N95 respirators and enhanced ventilation.
