October 4, 2020   |   6:09 a.m. PDT

What just a few hours of covering a #wildfire does to P95 respirator mask filters. #smoke #fire #n95 #napavalley #glassfire #photojournalism pic.twitter.com/oFd6uq2rHn

— Samuel Corum (@corumphoto) October 4, 2020

Photographers at a wildland fire may be able to use and tolerate a mask that traps 95 percent of the 0.3 micron particulates in smoke, but the devices are not practical for firefighters. (see photo above)

In case you are wondering, masks and respirators are divided into rating classes: N is not oil resistant, R is oil resistant, and P is oil proof. The number, such as 95, refers to the percent of particles removed that are at least 0.3 microns in diameter.

Be careful out there.