The New York City Health Department has developed this fact sheet to address some of the most common questions and concerns regarding mold. There are more than 100,000 species of mold. Some of the most commonly found are species of Cladosporium, Penicillium, and Aspergillus.
Mold is most likely to grow where there is water or dampness - such as in bathrooms and basements.
Most types of mold that are routinely encountered are not hazardous to healthy individuals. However, too much exposure to mold may cause or worsen conditions such as asthma, hay fever, or other allergies. The most common symptoms of overexposure are cough, congestion, runny nose, eye irritation, and aggravation of asthma. Exposure can occur if people inhale the spores, directly handle moldy materials, or accidentally ingest it. Also, mold can sometimes produce chemicals called mycotoxins.