How safe is it to quickly unmask for an ID check, oral temp check, PCR swab, etc?
Here's my best attempt at a systematic experiment with my PortaCount. I put my phone to video record the particle count inside the mask displayed on the machine screen, with the machine in Count mode.
Using my best regular disposable respirator (Aura 9321CN+), I put it on, waited for the particle count to stabilize, inhaled, took it off for a few seconds, did a big exhale as I put it back on, then held my breath after the exhale. I made a noise just before doffing and when I couldn't hold my breath any longer after the re-don as a signal for recording the two conditions. I repeated this five times.
Then, I watched the videos and recorded three particle counts for each condition.
Here are the numbers. Tested at ambient outdoor particle count (14-15k right now 😵). If it's safe to unmask with the purge, the particle count post-purge should be in the same ballpark as pre-purge.
Conclusion: Brief unmasking with purge appears to be safe!
Any comments/criticisms/suggestions regarding my method and results would be really appreciated! If I haven't come up with the best method to test this, I really hope we do because this is so crucial for all of us to know.
@ericbkennedy @eddericu
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