I've previously posted my university credentials with aerosol measurements & mitigation measures. Aerobiological sampling with sartorius membrane filter and CNC instrument. I also co-patented an isokinetic sampling assembly for use with CNC particle counting. 

I bring this up knowing fully well that masks/filters do indeed mitigate viral loads if they are KN95 or better and fitted properly. My research also shows that nonwoven masks/filter will also mitigate viral exposure.

 

I was disappointed from your attachment that the sources debunking the effectiveness of masks were vague or misleading.