Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
Why masks with valves do not slow the spread of COVID-19 (2 of 2): Video Transcript (Including Description of Visuals)
[0:00 – 0:10] We see side-by-side images of three mannequins in front of a black background. Above the image are the words, "Light scattering technique 125 fps."
The left mannequin is labeled "Unfiltered breath" and is wearing a mask with a valve; when it expels air, we see a white plume directed downward from the valve.
The center mannequin is labeled "Filtered breath" and is wearing an N-95 mask without a valve; when it expels air, the only visible indication are some white wisps where the neck and mask meets.
The right mannequin is labeled "Unfiltered breath" and features the mannequin without any mask; when it expels air, we see a white plume of air exiting the mouth and leaving the screen.
Text reads, "The CDC recommends that people wear masks in the public to slow the spread of COVID-19. However, masks with exhalation valves allow exhaled breath to escape unfiltered.
[0:10 – 0:20] Visualization repeats. Text reads, "Cover smart. Do your part. Slow the spread."
Read the accompanying news article.