You don't really need to spend $400 on a air purifier and providing the filter is cleaned regular you shouldn't have problems, vineagar is an excellent mold remover.
My children didn't eat solids till they were a year and over they survived on fromage frais and milk. They didn't like ground rice, they would eat a very, sloopy farleys rusk, runny egg yolk and runny instant oatmeal, my son really went for spinach cannelloni.
My daughter still ate very little till she was about 4yrs old. If you saw her now you wouldn't believe she hardly ate and now she's got good strong muscles far better than most of the kids at school.
Try not to worry, some kids eat when they're good and ready.