Prevalence Mold is everywhere. Inside, outside, in the air, and on many surfaces – mold grows wherever there is moisture. WHO estimates indoor dampness or mold affects 50% of houses in the United States, with areas such as river valleys and coastal areas experiencing much more severe conditions than the national average. The amount of water on or in materials is the most significant trigger of mold growth, and high moisture and relative humidity are necessary for optimal growth. Chapel Hill gets on average 47 inches of rainfall per year, which is higher than the national average of 39 inches. The Triangle (Raleigh/Durham/Chapel Hill) experiences average yearly humidity rates of 70%, with peak humidity in the mornings averaging 85%. Chapel Hill’s warm, humid climate creates a perfect environment for indoor mold growth, and the local news station, WRAL, reports mold and mildew are a common complaint. Mold can enter homes and buildings through open doorways, windows, vents,