Characterization of nanoparticle penetration of HVAC filter media

Penetration increases with increasing face velocity. MPPSs shift to the smaller particle sizes with increasing face velocity- down to 10 ∼ 15 nm at 1.0 and 1.5 m/s. At high face velocities, 0.5-1.5 m/s, clear bimodal penetration curves were observed, peaking at 10 ∼ 25 and 150 ∼ 200 nm, respectively. For highly charged filter, the first mode is higher than the second one while it shows reverse trend for medium charged filter. The single fiber theory predicted the nanoparticle penetrations well in the small particle size range and need to be improved in large particle size range.