Thread by @Smogdr

1/ Our new @EnvSciTech paper on #mask performance. Take-home stuff follows:

Quantitative Protection Factors for Common Masks and Face Coverings pubs.acs.org/doi/10.1021/ac…

2/ Most cloth masks have poor efficacy for aerosol <1 micron. The 7 #masks we tested are in use worldwide and were supplied by @WHO. Mask E is a KN95.

3/ We (re)introduce mask “protection factor” (PF) b/c it’s easy to understand. A PF of 10 means wearing the mask will reduce your aerosol intake by 10x (i.e., 10 times fewer particles are inhaled).

4/ I like using PF to describe masks better than “collection efficiency” b/c the latter depends on particle size while PF takes size distribution into account. An 80% efficient mask for 1-10 micron particles might give a PF of 4 for COVID but a PF of 2 for wildfire smoke.

5/ Leaky masks can contribute to virus spread because mask effectiveness is reduced (read: we have been wearing leaky masks that allow aerosol to get past the mask)...however, any mask is still better than #nomask.

6/ Waited to share this because I felt the results are more defensible after peer review (which took 3 months...ugh); it’s also #OpenAccess.

7/7 The #WHO funded this work, so they deserve a lil' credit for supporting research that #COVIDisAirborne and aerosol transmission is worth studying! :-)
@jljcolorado @kprather88 @linseymarr @jljcolorado @HuffmanLabDU