Did you even bother to look up basics of HEPA filters? They require an initial pressure drop of 300 Pa (https://en.wikipedia.org/wiki/HEPA#Specifications https:

Did you even bother to look up basics of HEPA filters? They require an initial pressure drop of 300 Pa (https://en.wikipedia.org/wiki/HEPA#Specifications https://en.wikipedia.org/wiki/HEPA#Specifications), which is beyond reach of any household fan. When the filter bcomes clogged, the pressure drop will increase even higher. Updated: Grammar