FIG. 9.

A human cough: mechanisms of airborne saliva droplet’s transport, breakup, dispersion, and evaporation. This figure shows different cloud kinematics (elongation and rotation) depending on the wind shearing force; the gravitational or settling forces; and the evaporation rates. Wind blowing from left to right at speeds of (a) 4 km/h and (b) 15 km/h. The environment is at ambient temperature, pressure, and relative humidity of 20 °C, 1 atm, and 50%, respectively, with the ground temperature at 15 °C.