TABLE 1.

Exhaled aerosols generated from human respiratory activities.

	Breathing	Coughing	Sneezing	Speaking/singing
Origin	Small airways	Mouth, larynx, large airways	Nose, large airways	Vocal cords, oral passages
Mechanism	Film bursting	Expulsion of compressed air, turbulent flow in upper and large airways		Fluid filaments (vocal cords), fluid film (mouth)
Size range	0.01—2 µm (mean: 0.3–0.7 µm)	<1 µm—>100 µm		1–5 µm (vocal cords) < 1—100 µm (mouth)