Molds are a type of fungus. They grow best in warm, moist environments and they survive by digesting decaying organic materials. Because they do not use chlorophyll to produce food, molds do not need sunlight to survive. Without mold, the entire world would be overrun by dead plant matter, so it's an important part of the environment.
WHY DOES MOLD GROW IN RESIDENTIAL HOMES?
The key to mold growth is the level of moisture in the environment. Mold will grow in any environment that is sufficiently moist that also contains any kind of food source. Common food sources for mold in the structure of the home include drywall, window frames, carpeted or uncarpeted flooring, bathroom tile, and interior insulation. Mold developing in the structural materials of a basement or crawlspace may require special attention. Mold may also develop on furniture.
Common sources of moisture that could lead to indoor mold include condensation from high humidity or large temperature differences, roof leaks, flooding, plumbing leaks, or excessive humidity.
WHAT HEALTH PROBLEMS ARE CAUSED BY MOLD?
Exposure to environmental mold can lead to skin irritation, breathing difficulties, allergic reactions and headaches. Mold can be an irritant, causing a burning sensation to the skin, lungs, nose, throat or eyes. It can trigger asthma attacks in people who are allergic, and even non-allergic asthma sufferers may experience worsened symptoms because of exposure to indoor mold. Symptoms of allergic reaction include sneezing, red eyes, runny nose or the appearance of skin rash. The EPA reports that repeated exposure to mold can bring about sensitivity and health problems, so it is important to put an end to mold exposure as soon as possible.
Molds can also produce mycotoxins, which are toxic substances that may be found either within or on the surface of mold spores. Mycotoxins can enter a person's system via ingestion, inhalation or skin contact. Aflatoxin B1 is the best-known mycotoxin; it is a potent carcinogen, the inhalation of which can cause lung cancer. It is produced by the molds Aspergillus parasiticus and Aspergillus flavus.
Those who suspect an indoor growth of mold should begin by having the area tested by a professional. Many contractors offer free testing. Mold sampling should be performed by those who have specific working knowledge of sampling methods and protocols, including those recommended by the American Conference of Governmental Industrial Hygienists or the American Industrial Hygiene Association.
Investigations often disturb potential areas of growth. It may be necessary, for example, to remove sections of wallpaper to examine drywall or sections of carpet to test floorboards. Either action may release mold spores into the air.