FIG. 1.
Concentration of airborne particles of diameters 5.0 µm–10.0 µm as a function of time as measured using a handheld particle counter (purple symbols) and the laser sheet diffraction technique4 in a poorly ventilated space of volume 8 m3. The other channels of the particle counter yield comparable results. The arrow indicates the moment of coughing, coinciding with a sharp increase followed by an exponential decay, with a half-life of roughly 4 min. The yellow line is a guide to the eye. The green data points are the reference data from the laser sheet technique published previously in Ref. 4.