The Latex Particle Challenge tests the Particle Filtration Efficiency (PFE), which is the mask’s ability to keep out dust, pollutants and other non-viable particles in the air. The PRO mask has an average PFE of 99.76%.

The Latex Particle Challenge tests the Particle Filtration Efficiency (PFE). The Particle Filtration Efficiency (VFE) is the percentage of non-viable particles that is blocked by the mask. Essentially, it tests the mask’s ability to filter out dust, pollutants and other particles in the air. A higher PFE means the mask is filtering out more of the particles in the air. The PRO mask has an average PFE of 99.76%.

Non-viable particles are ones that are not made of living microorganisms, however, they can act as surfaces for transporting bacteria and viruses. Particles can include a large range of environmental toxins and pollutants such as PM2.5 and PM10, as well as household dust and pet dander. In general they are larger than viruses or bacteria, but they can range significantly in size.

In order to test the mask’s PFE, small particles of latex were passed through the mask and the number that went through was counted using a laser particle counter. To calculate the PFE, the number of particles that passed through the mask is divided by the total number of test particles.