Particle size.
Yes, partial size. The virus is 1/4 the size of a smoke particle. If you can smell smoke through the mask, then is is not capable of blocking a virus. What is so frightening about this, the sizes are FACTS (look them up), smelling smoke through a mask can be done easily, you can prove that yourself. But facts don’t count when it comes to politics. We live and die in a sea of opinion.