I brush my teeth next to the tank all the time.
Although, I'm not sure that I could bare to put my fish through something like this though...get it (bare, not bear)? Oh, nm.....
The wife burns candles in the house quite a bit, never directly next to the tanks before but certainly in the same rooms over the years. Can't say that I've noticed anything bad come from it. You should see what our air filters look like after about a month though.