As a retired medical professional with a master’s degree in public health, I am responding to Val Mullen’s “scientific” view point on mask wearing for COVID-19 protection. (letter, Oct.7)

First, some explanation:

This teeny virus which scientist Mullen states is 125 nanometers is carried by bodily fluids varying in size from misty aerosol droplets to spit balls. As anyone who has worn a mask for 15 minutes can attest to, a lot of those droplets are caught in the mask. One also sees this moisture on a cold winter’s day when your breath freezes on exhalation. Cover it with a scarf...