People worrying about whether or not filtration works, based on the small size of the COVID virus are getting worked up about the size of single viruses.

However, you don't cough or sneeze or exhale individual virus particles. You expel droplets. Which are much bigger, and relatively easy to filter. Some science on this:

Sneeze particles/droplets: https://royalsocietypublishing.org/doi/full/10.1098/rsif.2013.0560#d3e1463

Size distribution of coughed particles/droplets:

https://www.ncbi.nlm.nih.gov/pubmed/18158720 

So, you can relax about this "my mask only filters down to .03 microns and a COVID-19 virus is smaller than that"

For more information, please re-read.