Activated carbon PM2.5 filters are made from the same advanced materials used for respirators like the N95 and KN95. You might wonder why they’re referred to as “PM 2.5″… That’s because these filters were initially developed by Asian companies as a way to protect people from the negative health effects of Particulate Matter 2.5 (2.5 micrometers and smaller). PM 2.5 is the smallest – and usually the most harmful – form of airborne particulate pollution.
It’s true that Airborne virions like the Coronavirus are smaller than PM2.5 (the Coronavirus’s lipid envelope is about 120 nanometers across, or 0.12 micro meters). But remember: 2.5 micrometers is the MAXIMUM size of particulates these filters are designed to capture. Studies suggest this material also captures nano-particles of a similar size to the Coronavirus with a high degree of efficiency (approx. 95%), making a pm2.5 filter Coronavirus approach potentially the right one to take.
Because PM 2.5 filters utilize a combination of mechanical and electrostatic mechanisms to stop particulates, the air resistance will increase overtime as particulates are trapped in the barriers. Removed the filter as soon as it becomes noticeably more difficult to inhale. Generally, you should feel no difference until 16-24 hours of continuous use (about 1-2 weeks of casual use for daily activities). After that point, the resistance will begin to gradually build up as more particulates are trapped by the advanced melt-blown fibers. If you are using the filter everyday in the workplace, we generally recommend replacing the filter at the end of a 40-hour week.