1. Product Overview
Filtering respirators, which are also called disposable respirators, are subject to various regulatory standards around the world (see examples below).
Since N95 and KN95 masks are rated to capture 95% of 0.3 micron particles, people will often assume that masks can’t capture particles smaller than 0.3 microns. For example, here’s an infographic in the South China Morning Post claiming just this. They even go so far as to say “N95 respirators protect the wearer from breathing in particles bigger than 0.3 microns in diameter.”
However, that’s not true. Masks are actually more effective at capturing smaller particles than many people believe. Empirical data finds that masks are actually highly effective at capturing smaller particles.
Both ratings require masks to be tested for filtration efficiency at capturing salt particles (NaCl). Both are tested at a flow rate of 85 L/minute. However, there are some differences between N95 and KN95, highlighted here.