Figure 2. Influenza viral RNA collected from coughs using the NIOSH two-stage aerosol sampler.

Influenza viral RNA was detected in the cough aerosols from 32 of 38 influenza-positive patients. This plot shows the number of viral copies per cough detected in aerosol particles collected in sampler tube 1 (>4 µm), tube 2 (1 to 4 µm) and the filter (<1 µm) for each patient, ordered from minimum to maximum. The particles collected in tube 2 and on the filter are respirable (able to reach the alveolar region).