Researchers have invented a prototype new form of high-performance air purifier that promises zero harmful waste and is 99.999% efficient in removing common bacteria and viruses::New purifier and filtering foam invented by University of Bath engineers is ready for commercialisation, seeking partners
You know if you get a 20x20" air filter, the cardboard frame type that are inserted into AC units, and you tape it to a square room fan, it will work far far better than any available air purifier. After tons of research into which purifiers work best to combat asthma, I ended up with room fans and 20x20 AC filters. The filters have different ratings, if they filter too well then air won’t pass through, so you want the next best rating.
This is very good advice. I’ve made a couple - far from beautiful or quiet, but very effective and very cheap.
This is a good page from an early DIY promoter: How to Make a DIY Air Purifier
We live in a small (12ftx28ft) house where we heat with a wood stove and have pets so our dust factor is pretty high.
I use 10x10 merv13 filters and a modified bathroom exhaust fan that sits in my rafters. It completely changed our air quality. I change the filters when they get gunked up every 10-14 days which may be a bit expensive at ~8 bucks each filter, but it is worth it for the clear nose and sinuses!