When combined with a fitted adjustable cotton masks, PM2.5 filters can block the vast majority of airborne particulates, with significantly less inhalation resistance than a sealed n95/kn95 respirator. In laboratory testing, cotton masks + PM2.5 filters restricted inhalation by less than than 71 Pa, less than 25% the max inhalation resistance of a NIOSH-certified N95 respirator
A fitted face mask with a PM2.5 filter offers a high degree of filtration from particulates and aerosols. The PM2.5 name comes from these filters’ original use as protection against Particulate Matter 2.5, the smallest and most dangerous form of air pollution. Aerosol particulates that may harbor viruses are much smaller than most particulate matter, but research has shown a PM2.5 filter can capture nanoparticles similar size with a high degree of efficiency (approx. 95%), and lab tests show a PM2.5 filter with a properly-fitted cloth mask can reduce total airborne particulates by as much as 90%.
FYI: pm2.5 filters provide both mechanical and electro-static protection. They don’t lose effectiveness so much as become clogged over time, so we recommend using them for a total period of between 16-24 hours of active use, and around 40 hours of seated use. Store unused filters in a dry, dark place to maximize shelf life.