Many people are suffering from poor air quality in their homes from factory farms. They need an inexpensive solution as they cannot afford to move. They are incurring particulate matter including nano particles, as well as ammonia and Hydrogen Sulfide.
Just to get the ball rolling, I would suggest exploring activated carbon adsorption, scrubbing, and/or biofilters. These options would likely be the most reasonable from a DIY/cost/safety perspective for particulates, ordors, ammonia, H2S.
I would ensure the source is ambient air vs. household water as treatment would be different.
Literally just stumbled on this site. LMK if I can help more with specifics.
Great suggestions! I've also seen some stuff up at #air-filters -- one by @Melissa here: #12171
HEPA filters are a great choice for reducing particulate matter. Unfortunately, they are relatively ineffective for treating the gaseous compounds of concern (NH3, H2S, odors).
An easy addition may be to use that setup (#12171) with a combined HEPA/Activated Carbon filter (e.g. https://www.homedepot.com/p/Activated-Carbon-Passive-Window-Air-Purifier-AC-736/206173822). This would remove both particulate matter and the gases.
Additional steps could be taken to further improve the effectiveness for these compounds (impregnated AC/proper sizing/design) and/or integrate other techniques (trickling/scrubbing for NH3). Buying raw GAC or powdered AC would likely be cheaper and enable different design applications. You could even make your own if you're so inclined.