is air cleaners / purifiers really works?

I have severe respiratory problems and allergies and I have been using an air purifier for years and it helps me tremendously. I wouldn’t think of not having one running in my home. But it depends on the brand and the type of technology used. The HEPA filters are usually the ones recommended and they are good for removing large particles like dust or pet dander, but more limited in removal of very small particles like mold and bacteria. The technology that I found to be the most effective for air purification is photocatalytic ionization. Research showed a 90% reduction in mold and a 77% reduction in bacteria in a 5 day period in a 750 sq ft area. This unit also requires no fan and no filter changes. It is called the Aclare from Advanced Air Solutions. Very effective.