Classification of anti-particulate masks

In Chinese standards, anti-particulate masks are divided into KN and KP categories. KN masks can only filter non-oily particles, such as dust, acid mist, paint mist, microorganisms, etc. The suspended particles in air pollution are mostly non-oily. KP masks can filter both non-oily particles and oily particles. Oily particulate matter such as: lampblack, oil mist, etc. According to the difference of filtration efficiency, there are differences of 90, 95, 100, which respectively refer to the lowest filtration efficiency of 90%, 95%, and 99.97% under the test conditions specified by the standard. The KN90 mask that you can often see on the market is a mask with a minimum efficiency of 90% for filtering non-oily particles under the test conditions specified by the standard.