So I was watching The Weather Channel and they said the best way to improve air quality in your home is to have a house plant. "Well duh" it seemed. But although we spend hundreds of dollars to heat / cool our greenhouse during the whole year, and I can enjoy flowers even in the dead of January, I DON'T HAVE A SINGLE PLANT INSIDE MY HOUSE!
Problem fixed! Although I'll still run the humidifier to help baby get over his SECOND cold. boooo :(