to achieve room air quality standard, protect environment and people's health.

1) 1st layer called Primary filter for remove big particles/smoke/dust. 

2) 2nd layer called Medium efficiency F8 class filter to remove smaller particles/smoke/dust. (>=1Mircron).

3) 3rd layer called main filters, Include 1 layer activated carbon filter & 1 layer H13 class HEPA filter

to remove small particles, smoke and light smells.