1CFM is 0.028 cubic meters per minute. CFM is a unit of gas flow, the full name is cubic feet per minute. It means the air flow of a certain volume through the filter in unit time. Air flow is the amount of air flow per unit time. China generally uses m3/h air volume units, and foreign countries also use British air volume units cfm (cubic foot per minute). That is ft3/min cubic feet/minute, the two are converted into: 1cfm≈1.7m3/h. Extended reading: Orifice Plate Flow Meter