... / 30 min/ 60 min/ 90 min, continuous mode4. Timing Automatic Working: It’s possible to set 2:00AM to start working, after ... room, you will feel bad, smell foul air; actually, it’s due to benzene, methane and etc.School (eg. Nursery school ... weak, and stay in a same classroom for longtime, it’s easy to be Cross-infection. If you use ozone when ...