The residue of dried droplets that may remain suspended in the air for long periods, may be blown over great distances, and are easily inhaled into the lungs and exhaled.

microscopic particle (1 to 5 microns in diameter) produced when a person coughs, sneezes, shouts, or sings. The droplets can carry M. tuberculosis that remain in the air by normal air currents in the room.

Airborne particles of about 1 to 4 microns that are the residue after evaporation of expelled droplets. They can carry airborne infection that can be transmitted if they land on eyes or are inhaled by a non-infected person or animal.