I’ve noticed something peculiar every time I go on a long road trip, or am spending a lot of time in the car in the summer, then usually it happens when I’m travelling back and forth from the town visiting friends, and sitting in the car for about 3 hours at a time in order to do so; I return home at the end of the weekend and I’m instantaneously sick. It was a mystery for a while, even though I now I guess it’s my air conditioner to blame. I wake up the next morning to find that I have a sore throat and horrible sinus congestion. I thought it was pollen irritations, or perhaps the air vents in my old car contained something irritating to my mucous membranes, but as time goes on I’m convinced that being in the direct line of AC for hours at a time is what affects me. I’ve gotten more evidence, as my girlfriend has recently experienced the same thing following a long car ride with the AC blasting the whole way. I was smart enough to turn my air vents off, or direct them away from my face, however she took the air conditioner on full force. The next morning, she woke up so plugged and always coughing; he’s never sick, so I’m particular that it was the car’s AC that caused her ailments. It’s too late to help him now, but at least he’ll be somewhat aware of the pending dangers of using high powered air conditioner settings in the car for future use.