HEPA Filter has the characteristics of small wind resistance, large dust capacity, good filtering effect and not easy to be damaged. For the diameter of 0.1 μ m, the effective rate can reach 99.7%, and the removal efficiency of particles with the diameter of 0.3 μ m (1 / 200 of the hair diameter) can reach more than 99.97%. It is the most effective Filter medium for smoke, dust, bacteria and other pollutants. It can control the indoor PM2.5 concentration at 1 μ G Even a few micrograms.