Just woke up after a very long night of breathing treatment with our daughter. She has asthma and although she hadn't had an attack in over a year she had one last night. The likely cause was Disney on Ice. We went to it just before the attack and unfortunately they are using some very nasty smoke machines. I remembered from long long ago when they used dry ice for smoke/fog during Disney on Parade, but this stuff smelled like burnt sugar. While they announced just prior to the show that they would have smoke effects, they claimed they were safe. They are not. So be warned if you have kids with any type of breathing problems, don't go.
Even my wife and I noticed that our eyes and throat were getting irritated by the end of the show. The truly sad part is that the smoke was not needed for theatrical effects in 99% of the show but they kept pumping out the smoke like a factory. I suspect it was simply to make it impossible for people to take photo as that seemed the only thing it really did beside irritate the eyes and throats of the audience... Was quite telling when I heard the couple complaining when we were leaving as they woman was a smoker about to light up.