In the winter, we cannot afford this luxury because of high heating costs. In the summer months, we generally keep the windows closed to keep in the cool air. In a closed building without ozone, bacteria runs rampant, spores and mildew grows in all those nooks and crannies, pet odors permeate the drapes and furniture, the toxins in cigarette smoke invade our lungs, and the formaldehydes hinders us from getting a good nights sleep. With it you have fresh air. Indoor molds are found mostly in damp areas like bathrooms and around windows, basements, HVAC ducts, damp ceilings and walls, wet carpets and under the house.
Poor ventilation is the biggest cause in bathrooms.
Exhaust fans can be installed improperly and should be checked if molds are a problem. The most common molds are Alternaria, Aspergillus, Cladosporium and Penicillium. Some of these molds or fungus are also found in many common medicines and foods. Some molds produce toxins to protect their environment. The toxins or fungus, when inhaled are a significant cause of common allergic reactions, altered immune function, asthmatic reactions, chronic sinusitis, depression, diarrhea, fatigue, headaches, irritability, liver damage, nose bleeds, respiratory dysfunction, or sore throat.