Airborne droplet nuclei

Airborne droplet nuclei develop when the fluid of pathogenic droplets (1-5 µm in size; micrometre = one-thousandth of a millimetre) evaporates. They are so small and light they may remain suspended in the air for several hours. Thus, they may also infect persons entering a room which has been left by a patient long ago. Also, airborne droplet nuclei can be widely dispersed by air currents. Tuberculosis, chickenpox, measles and possibly also influenza may be transmitted this way.