I Just had to add my two cents re Air Conditioning filters. My mother lived in this very expensive, assisted living facility in Florida for 5 years. I only saw them change filters once and it was disgusting all the debris. As a result she was sick constantly with frequent URIs and ended up in the ER 3 times. Moved her to another facility less expensive without all the entertainment frills etc. But filters were mandatorily changed every 3 months. It has been 4 years and she has not been sick once since she has moved there and she will be 90 this April. So this was certainly an eye opening experience for me. Check those AC filters often!!!!
I agree 100 percent that air conditioners give sinus infections. Every summer i get a sinus infection when air conditioners are in full swing everywhere you go. I avoid them at all costs in the summer.
Out of curiosity, I read your theory about ice cream and have to disagree. I have eaten ice cream ( all kinds ) since I was a kid ( I'm 43 ). I never had sinus problems...until, 7 years ago, when I met my husband, and started sleeping in an air-conditioned room. He practically "lives" on chocolate milk, and loves his air conditioner. He constantly has sinus trouble. I believe the air conditioner is the culprit.