Influenza virus copy number in aerosol particles exhaled by patients with and without wearing of an ear-loop surgical mask.

<p>Counts below the limit of detection are represented as 0.5 on the log scale.</p

Exhaled breath collection system.

<p>Each volunteer sat as shown with face inside the inlet cone of the human exhaled breath air sampler inside a booth supplied with HEPA filtered, humidified air for 30 min while wearing an ear-loop surgical mask. Three times during the 30 min each subject was asked to cough 10 times. After investigators changed the collection media, the volunteer sat in the cone again, without wearing a surgical mask, for another 30 min with coughing as before.</p

Participant's sex, symptoms, temperature, and influenza virus type.

a<p>Self-reported.</p>b<p>At time of exhaled breath measurement.</p

Copy number coarse and fine exhaled particles without surgical mask by day since onset of influenza symptoms.

a<p>Because there were only single cases studied on day 0 (day of onset) and on day 5 since onset of symptoms, only data for cases studied on days 1 through 4 after onset of symptoms are shown.</p

Descriptive statistics.

a<p> <b>At time of exhaled breath measurement.</b></p