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Bad info = public confusion = bad decisions = higher risk.

I was interviewed by a reporter this week who said that a medical doctor had told her that portable HEPA filters do not work as the virus is too small to be captured by a HEPA filter. More ...

2/ This was my look right before my head nearly exploded. My first response was that medical doctors should not speak about filtration of particles, or even particles, if they are not qualified to do so.

Bad info = public confusion = bad decisions = higher risk.

3/ The SARS-CoV-2 virus is transported in particles (its ride share) emitted by an infector. HEPA filters effectively remove all particle sizes of relevance. Even if the virus existed as a viable single particle w/ diam of 0.1 to 0.12 microns (it does not) ... (more)

4/ HEPA filtration would still be highly effective. Why? High Efficiency Particulate Air (HEPA) filters should remove 99.97% of particles at 0.3 microns as the WORST case - 0.3 micron particles have the greatest penetration (lowest removal efficiency at 99.97%).

5/ The removal efficiency increases with larger particles and also with smaller particles for which Brownian motion plays a dominant role in removal to filter fibers.

Bad info = public confusion = bad decisions = higher risk.