A recent study from Su et al tests the effects of ultraviolet germicidal irradiation (UVGI) on the amount of culturable airborne bacteria in elementary school classrooms. As expected, they found lower concentrations of these bacteria with UVGI treatment. Only the first page of the paper is available, unfortunately, so perhaps this is already addressed, but it seems relevant which species of bacteria are being killed (I’m guessing UVGI doesn’t differentiate between good and bad bacteria, much like antibiotics). Perhaps sterilizing the air in classrooms isn’t such a great idea from the “hygiene hypothesis” stand-point. Also, just opening the windows or having better ventilation in general could be enough to help children with allergies and asthma. As a long-time sufferer of dust allergies, I definitely would have appreciated a cleaner environment in my classroom as a kid. But I was only one kid in a sea of about 30 and the custodial staff definitely weren’t being paid enough to spend extra hours cleaning. So maybe UVGI is a fast and efficient way to help kids with asthma and allergies feel less sick in their own classrooms. I am interested to see the follow-up to this research and how good of an idea it is to actually irradiate an entire classroom regularly.