Molds are simple, microscopic organisms that are present virtually everywhere both indoors and outdoors. Molds are fungi and are needed to break down dead material and recycle nutrients in the environment. For molds to grow and reproduce they need only a food source such as leaves, wood, paper, or dirt - and moisture.
Common asthma triggers found in damp areas both indoors (bathrooms, basements) and outside (grass, leaf piles, mulch).