Coronavirus and homemade tools

[Saltfever]

. . . For example, I'm looking at this 3M air filter selection guide. Some of the filters are labelled as filtering viruses. What are those filters made from?

The chart is misleading. Most likely because there is no accountability on a chart. Printing a label on a product is a serious matter and can subject you to "Truth in advertising" litigation.

This is the actual claim on the filter; "Particles that can carry a virus" is a big difference" from the insinuation in the chart that the filter can actually trap a virus. Most viruses are less than 200nm in size. The Filtrete 2200 is not even rated as a HEPA filter.



The text you see on the left (above) is what is printed inside my marked-up red circle on the Filtrete 2200 filter package.

Sorry about the pic orientation. Pics get flipped during uploading and I have no idea how to control it. I have no idea how a 3rd pic below was installed and a few attempts at edit could not delete it.