Images in Clinical Medicine
Coughing and Masks
N Engl J Med 2009; 361:e62December 24, 2009
- Article
Video
Real-Time Schlieren Imaging of Coughing.
Coughing can transmit infectious agents, such as influenza virus, and it has been assumed that wearing a mask limits transmission of these agents. Schlieren optics can effectively visualize the dispersion of expelled air during coughing. Both the standard surgical mask (Panel A) and the N95 mask (or respirator) (Panel B) provide a barrier that helps to halt the forward momentum of the cough plume. Without the barrier provided by a protective mask, a cough can propel a strong turbulent jet of air a distance of 1 to 2 m from the mouth (Video 1). Although there is some leakage around the sides and through the front of both the surgical and the N95 masks, most of the escaped effluent is carried upward in the rising thermal plume (Videos 2 and 3), reducing the risk of transmission. The N95 mask provides a better seal than the surgical mask, but as can be seen in the video, it still does not completely contain the cough effluent.
Julian Wei-Tze Tang, M.D.
National University Hospital, SingaporeGary Settles, Ph.D.
Pennsylvania State University, University Park, PA- Citing Articles (1)
Citing Articles
1
Samantha M. Tracht, Sara Y. Del Valle, Brian K. Edwards. (2012) Economic analysis of the use of facemasks during pandemic (H1N1) 2009. Journal of Theoretical Biology 300, 161-172
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