Mold facts:
- Some types of mold are commonly known as mildew.
- Mold may live indoors or outdoors and thrives in damp, warm, and humid environments.
- Although shower stalls and basements are typical moist areas prone to the growth of molds, any moist area in the household may harbor mold.
- Allergic reactions to mold are the most common health effects and risks of mold. Mold allergy symptoms and signs include
- wheezing,
- rash,
- watery eyes
- runny nose,
- itchy eyes,
- coughing, and
- redness of the eyes.
- The best way to prevent mold in residential areas is the control of moisture.
- There are no EPA or government standards that have been established for mold or mold spore levels in residential or commercial areas, so it is impossible to prove that a building or room is in compliance with any regulations concerning mold exposure.
Molds are various types of fungi (singular = fungus) that grow in filaments and reproduce by forming spores. The term mildew is sometimes used to refer to some kinds of mold, particularly mold in the home with a white or grayish color or mold growing in shower stalls and bathrooms. Mold may grow indoors or outdoors and thrives in damp, warm, and humid environments. Mold can be found in essentially any environment or season.
The most common types of household mold that are found indoors include Cladosporium, Penicillium, Alternaria, and Aspergillus. Stachybotrys chartarum (also known as Stachybotrys atra and sometimes referred to as "black mold") is a greenish-black mold that can also be found indoors, although it is less common than the other types of mold found in homes. Stachybotrys grows on household surfaces that have high cellulose content, such as wood, fiberboard, gypsum board, paper, dust, and lint. There are types of mold that can grow on substances as different as foods and carpet.
Molds reproduce by forming tiny spores that are not visible to the naked eye. Mold spores are very hardy and can survive under conditions in which mold cannot grow, such as in dry and harsh environments. These spores travel through outdoor and indoor air. When the mold spores land on a surface where moisture is present, mold can then start to grow.
Outdoors, molds play a role in the decomposition of organic matter such as dead trees, compost, and leaves. They are most common in damp, dark areas or areas of decomposing plant life. Indoors, mold is often found in basements or shower stalls. Indoor mold in residential areas has the potential to cause health problems and can destroy surfaces and objects where it grows.
Where can mold be found in homes?
Although bathrooms (particularly shower stalls) and basements are typical moist areas prone to the growth of molds, any moist area in the home can harbor mold. Drywall, ceiling tiles, carpets, furniture, ductwork, roofing, paneling, wallpaper, under sinks, and the areas around plumbing pipes are examples of areas in the home that can become infested by mold if the requisite growing conditions are present.
Mold from the outdoors can enter the home through open doors, windows, and vents. It may also become attached to clothing, shoes, and pets and therefore be carried indoors.
Mold can have many different colors and sometimes appears as spots. Additionally, a musty odor may be present. Mold growth may also be hidden underneath carpeting, on the back side of wallpaper, and behind drywall or paneling. Saunas, greenhouses, and construction areas are places where mold is commonly found.
What kinds of health risks may be linked to mold? What are symptoms and signs of mold allergy?
Molds produce irritating substances that may act as allergy-causing substances (allergens) in sensitive individuals. Furthermore, some molds produce toxic substances known as mycotoxins, but mold itself is not poisonous or toxic. The conditions under which some molds produce toxins are poorly understood, and the presence of mold, even a mold that is capable of producing toxins, does nor always imply that toxins are being produced. Mold may not cause any health effects, or it may lead to symptoms in people, including adults and children, who are sensitive to molds.
Allergic reactions to mold are the most common health effects of mold and are therefore the greatest health risk related to mold. Allergic reactions may happen immediately or develop after a period of time following exposure. Both growing mold and mold spores may lead to allergic reactions. Symptoms and signs of mold allergy may include
- sneezing,
- runny nose,
- coughing,
- wheezing,
- watery eyes,
- redness of the eyes,
- itchy eyes,
- skin irritation or rash.
Sometimes, people may develop severe reactions to mold exposure. Symptoms of severe reactions, which are uncommon, include fever and difficulty breathing. People with compromised immune systems or those with chronic lung disease can develop serious infections of the lungs due to molds.
It is not possible to predict the degree of severity of the health risks associated with mold in the home. Allergic individuals vary in their degree of susceptibility to mold, and the risk may also depend upon the extent and exact type of mold that is present.
In 2004, the Institute of Medicine (IOM) found there was sufficient evidence to link indoor exposure to mold with upper respiratory tract symptoms, cough, and wheezing in otherwise healthy people. Mold also was linked to the worsening of asthma symptoms in people who have asthma. Mold was also reported to be linked to hypersensitivity pneumonitis in individuals susceptible to this immunologic condition. This uncommon disease is similar to pneumonia and can develop in susceptible individuals after brief or prolonged exposure to mold.
According to the U.S. Centers for Disease Control and Prevention (CDC), "A link between other adverse health effects, such as acute idiopathic pulmonary hemorrhage among infants, memory loss, or lethargy, and molds, including the mold Stachybotrys chartarum (Stachybotrys atra), has not been proven."
Is it possible to prevent mold in the household?
The best way to prevent mold in the home is the control of moisture. Although it is impossible to eliminate all mold spores in an indoor environment, the mold spores will not grow in the absence of moisture, so controlling moisture is the key to preventing mold growth.
- Leaks in plumbing or other structures that lead to moisture buildup should be identified and repaired.
- Areas of leakage and water damage in the home should be cleaned and dried within 24-48 hours.
- Use of an air conditioner or air dehumidifier during humid seasons can help reduce the potential for moisture buildup.
- Avoid the use of carpets in humid basements and bathrooms.
- Using fans and maintaining good ventilation in the home can also help prevent or control dampness.
- Mold inhibitor products can be added to household paints.
- Keep indoor humidity low (ideally between 30%-50%).
- Use bathroom fans or open bathroom windows when showering.
- Appliances that produce moisture, such as clothes dryers and stoves, should be vented to the outdoors when possible.
- Adding insulation can reduce the potential for condensation on cold surfaces (such as windows, piping, roof, or floors).
According to the U.S. Environmental Protection Association (EPA), if visible mold is present on inspection, testing is usually unnecessary. There are no EPA or government standards that have been established for mold or mold spore levels, so it is impossible to prove that a building or room is in compliance with any regulations concerning mold exposure. Likewise, the CDC does not recommend routine sampling and testing of mold in the home. Tolerable or acceptable limits of mold exposure for humans have not been defined, and since individuals vary in their susceptibility to mold, testing cannot reliably predict the degree of health risks from any occurrence of mold.
When mold has previously been identified and cleanup procedures have been undertaken, sampling and testing may be carried out if necessary by qualified professionals to determine that adequate cleaning has occurred.
How should mold be cleaned up and eliminated?
Mold cleanup procedures are somewhat dependent upon the extent of contamination and the type of surface that has been contaminated. Large areas of mold may require the services of a professional contractor skilled in mold removal and remediation. Hard surfaces that harbor mold may be scrubbed with detergent and water, and these should be dried completely. Porous or absorbent materials (such as cloth, ceiling tiles, carpets, etc.) may have to be discarded if they become moldy. In some cases, a dilute solution of chlorine bleach (no stronger than 1 cup of bleach in 1 gallon of water) or stronger commercial cleaners may be needed to kill the mold.
Be sure to discuss any health concerns with a health-care professional prior to attempting mold removal if sensitive to molds. When washing with soap and water, rubber gloves are recommended, but for bleach and harsher cleaning agents, nonporous gloves (for example, natural rubber, neoprene, nitrile, polyurethane, or PVC) should be worn along with protective eyewear. Wearing an N-95 respirator (available at many hardware stores) can further limit exposure to airborne mold or spores when cleaning. Avoid touching moldy surfaces with bare hands.
After mold removal, it is important to prevent further regrowth of mold by keeping affected areas as dry as possible.