No one knows the answer to this question for several reasons. Individuals are very different with respect to the amount of mold exposure they can tolerate. Children under the age of one year may be more susceptible to the effects of some molds than older individuals. Measuring or estimating “exposure” levels is very difficult. “Exposure” means the amount of mold (microscopic spores and mold fragments) that gets into a person usually by breathing, but also by eating or absorption through the skin. For example, a building may have a lot of mold in the walls but very little of that mold is getting into the air stream. In that case the people working or living in that building would have little mold exposure.

Additional Resources:

http://edis.ifas.ufl.edu/cd047

http://www.aafa.org/display.cfm?id=9&sub=18&cont=234

http://www.epi.state.nc.us/epi/oii/mold/