I remember the first outdoor festival concert I went to. There were eighteen bands playing over the course of two days, out in the muddy field not far off from town. The point was to bring a tent or an RV and stay out in the woods the whole weekend, drinking beer and listening to live music. I remember this one guy there wearing an oxygen mask. He was rocking out in the middle of a muddy field, and wearing an oxygen mask! After the band finished he went back to his tent, which I saw was very large and had its own air conditioning unit attached. I had never seen a tent that had a private AC system before, so I was pretty impressed. It turns out the guy had severe breathing issues, and could only take off the mask when he was in his climate controlled tent. It had hardly anything to do with temperature control, it was all about filtering the air and improving the air quality to the maximum. It really impressed me, because here was a guy who had sunk a lot of money into portable climate control equipment just so he could keep rocking out. When the last band finished playing and we all started to leave, I went over and helped him pack up his air conditioner and load it into the back of his truck. He thanked me for my help, and told me that I should never start smoking, and that I should definitely invest in a good quality air filter.