Are your indoor mold levels higher than those outside?
Mold "can wreak havoc on people with sensitivities to mold or people with asthma. There are a number of places in your home that can be a breeding ground for mold.
One of the biggest mold offenders is your humidifier. Replace water often and clean the humdifier out with soap and water regularly. Wet carpeting can also harbor mold so keep your carpets clean and dry.