They are forced-air/furnace filters.
Comment on Air Purification
HerbGrower@slrpnk.net 10 hours ago
No fires here, how much traffic pollution do they remove and how much goes through?
Have wondered about making one, not sure where I would get HEPA sheets like that though, or a fan like that tbh. Don’t seem to be that common in the UK.
Unrefined@anarchist.nexus 10 hours ago
HerbGrower@slrpnk.net 9 hours ago
I don’t think we have those here
ProdigalFrog@slrpnk.net 9 hours ago They are also known as HVAC or MVHR filters, which appear to be available in the UK
Based on this chart, you’d want an M5 rated filter to remove car exhaust particulate, something like this (though I have no idea if that’s the best deal to be had, that site was just the first one that popped up from searching UK HVAC Filter).
cantstopthesignal@sh.itjust.works 9 hours ago
Check the particulate size of what you want to filter out and buy a filter that will filter that size or smaller. HEPA will go down to 0.1-0.3 microns.