Description

Molds are fungi that occur through nature and can grow on almost any surface. Mold particles are normally present in the air at all times, both indoors and outdoors, usually without any consequences for our health. Problems may arise only when the level of mold in the air becomes particularly high or if a person is sensitive to mold.

Some molds can cause allergic and respiratory symptoms, such as runny nose, sinus headaches, fatigue, sore throat, chronic cough, wheezing, breathlessness, and tightness in the chest. Like the seeds of a plant, mold spores can remain inactive in dry materials, such as soil, dust and clothing, for years. They can suddenly begin to grow when moisture increases. Mold particles can cause health effects without actively growing. But it is when molds grow unchecked that levels inside homes become high enough to be dangerous. Actively growing molds also release particles (spores and fungal fragments) and toxins (called mycotoxins) into the air, which cause health effects.

The most common indoor molds, aspergillus, penicillium and cladosporium, require moisture to grow, though some molds can grow in dry climates, such as alternaria, which is common in Arizona.

In most cases, mold is particularly a problem where humidity is high, plumbing drips, the roof leaks, or flooding has occurred. Therefore, basements, bathrooms and kitchens are the most likely locations for mold growth indoors. Mold can grow in building materials (such as drywall, paint, wallpaper), upholstered furniture, mattresses, carpets and carpet pads, and potted plants. Outdoors, mold is likely to grow in piles of leaves, weeds, grass, etc.

Health Effects

Immediate Health Effects

 
• If SWALLOWED, molds is Not Available
 
• If ABSORBED THROUGH SKIN, molds is Not Available
 
• If INHALED (SNIFFED OR BREATHED IN), molds is Not Available

Longterm or Delayed Health Effects

 
• Mold may cause some types of cancer such as liver cancer.
 
• Allergen
 
• Asthma Trigger

Other

 
• Allergy symptoms, such as cough, sore throat, nasal stuffiness, eye irritation or itching, headaches, especially in sinuses.
 
• Shortness of breathing, wheezing, asthma.
 
• Upper respiratory infections. Severe reactions may include fever and shortness of breath. People with chronic illnesses, such as obstructive lung disease, may develop mold infections in their lungs.  Individuals with compromised immune systems may also be vulnerable to respiratory infections due to mold exposure.
 
• Some molds can cause coughing up blood, nose bleeds, anemia.
 
• Some molds can cause skin irritation or rashes.
 
• Infants exposed to high fungal levels in the home may have an increased risk of lower respiratory illnesses such as croup, pneumonia, bronchitis and bronchiolitis.
 
• Eye, nose, throat irritation, fatigue, headache.
 
• Those with weak immune systems are at risk for opportunistic infections.
 
• Hypersensitivity pneumonitis, a condition resembling bacterial pneumonia, is uncommon but possible.

How Exposures Occur

Inhalation of Mold/Mold Particles Growing on Hard Surfaces

• Mold particles from mold growing in walls, floors, and other indoor surfaces can become airborne. 

Inhalation of Particles Present in Dust

• Molds can grow in the fibers of carpets, upholstery, and mattresses, or mold particles may settle into these fibers. When carpets and upholstery are disturbed, spores and particles may be released.

Inhalation of Mold Growing Inside Humidifiers and Air Conditioners

• Humidifiers, especially the cool-spray and evaporative types, are breeding grounds for mold. The mold will be released into the air along with the moisture.
  
  Air conditioners may also breed and disperse mold due to condensation of moisture inside the unit. Proper maintenance and cleaning is essential to prevent this.

Ingestion

• Mold can be touched and then ingested through hand-to-mouth contact. Some molds, such as those that are necessary to make cheese, are not harmful.

Forced Air Heating Systems

• Homes heated with forced air furnaces can spread mold that collects inside ducts. The air movement may also disturb mold spores that have settled inside the home.

 

Significant Statistics

A relative humidity of 30-50% is optimal in homes to prevent mold growth.

Biological Contaminants. U.S. Environmental Protection Agency.http://www.epa.gov/iaq/biologic.html

No one knows how many species of mold exist, but there could be more than 300,000 of them.

Mold: Basic Facts.  Centers for Disease Control and Prevention.  February 8, 2010. http://www.cdc.gov/mold/faqs.htm.

Outdoors, molds are beneficial because they break down dead organic matter such as leaves and dead trees.  They become a problem when they grow in indoor areas where sensitive people can develop reactions.

Mazur, Lynnette J., MD, MPH and Janice Kim, MD, PhD, MPH.  ” Spectrum of Noninfectious Health Effects From Molds.”  Pediatrics.  Vol. 118 No. 6 December 2006, pp. e1909-e1926 (doi:10.1542/peds.2006-2829)..  http://aappolicy.aappublications.org/cgi/content/full/pediatrics;118/6/e1909.

Solutions

How to detect molds

 
• Look for visible mold growth. Molds vary in color, which can be white, gray, brown, black, yellow, or green, and texture, which can be cottony, velvety, granular, or leathery. Some molds may simply look like a stain. 
   
    Mold may be present anywhere where water damage has occurred.  Look for signs of excess moisture or water damage such as leaks, standing water, water stains, or condensation problems, particularly on the ceilings (from roof leaks), in plumbing and under sinks, and around windows.
 
• Mold can usually be smelled. It has an earthy or musty odor. But people vary in their ability to smell mold, so don’t use this as your only method of detection.

How to minimize exposure to molds

 
• Find the Source of Moisture and Repair it.
    Repair leaky roofs and plumbing. Moisture-proofing walls and floors may be necessary in basements. If moisture is a problem in your bathrooms, kitchen or basement, install and use exhaust fans to pull out moist air. Air conditioners and dehumidifiers may also be necessary to keep moisture levels down.
 
• Clean or Discard Affected Materials.
    Wearing gloves and a face mask, scrub mold off of non-porous materials with a stiff brush, a non-ammonia detergent and hot water. A dilute solution of 10% household chlorine bleach (1 part bleach to 10 parts water) can be used to kill mold and mold spores, but is not necessary. (Be sure to ventilate well when using bleach.) Dry completely.
   
    Absorbent materials that become moldy should be replaced. Such materials may include sheet rock, insulation, plaster, carpet/carpet pad, upholstered furniture and mattresses, ceiling tiles, wood products (other than solid wood), and paper products. Simply drying and cleaning surfaces does nothing to eliminate mold spores that have penetrated inside the item.
   
    Do not vacuum moldy carpets or upholstery! Vacuuming disperses mold spores and will not remove all the mold spores anyway.
   
    **The amount of mold particles in air can increase greatly when mold is disturbed. Use rubber gloves, goggles, and dust masks when removing mold, and take measures to prevent spores from spreading throughout the rest of the home. Keep children away!
 
• Preventative Measures:
  
  
       
  • Maintain indoor humidity between 30-50%. You can measure humidity by using a hygrometer, which can be purchased at hardware stores.
       
       
  • Use exhaust fans or open windows in kitchens and bathrooms when showering, cooking, or using the dishwasher.
       
       
  • Vent clothes dryers to the outside.
       
       
  • Use air conditioners and dehumidifiers to reduce moisture in the air, especially in summer, but empty drip pans and clean them daily to make sure that these appliances don’t become moldy and contribute to the problem.
       
       
  • Inspect air conditioners for mold before each cooling season and have coils cleaned as needed.
       
       
  • Keep the doors between rooms and closets open.
       
       
  • Do not store dirty or damp laundry in closed closets.
       
       
  • Do not store firewood indoors.
       
       
  • Eliminate piles of leaves and decaying debris in your yard, especially near your house.
   

   

Alternatives

 
• Choose non-carpet floors, such as ceramic, tile, or wood (with a sealant), especially in bathrooms, basements and kitchens. Use area rugs which can be taken up and washed often.  For more information, see Carpets and Rugs and Floor Covering.
 
• Choose furniture with washable cushions.
 
• Put a plastic cover over dirt in crawlspaces to prevent moisture from coming in from the ground. Be sure crawlspaces are well-ventilated.
 
• Use air cleaners and filters after adopting the preventive measure listed above. Devices equipped with electronic or HEPA filters are best at removing mold, mildew, and dust from the air. But these devices will only remove the particles that are airborne, not those that have settled.
   
    Use of air conditioners has been shown to significantly reduce airborne concentrations of mold, probably because air conditioners reduce moisture levels and filter out particles.

For More information

Books, articles, factsheets and reports

Biological Pollutants in Your Home. CPSC Document #425. Consumer Product Safety Commission and the American Lung Association.

http://www.cpsc.gov/cpscpub/pubs/425.html

Mold in My Home: What Do I Do? California Department of Health Services, Indoor Air Quality, July 2006.

http://www.cal-iaq.org/MIMH_2006-06.htm

"Molds at School," Healthy Schools Network, Inc., November 2002.

http://www.healthyschools.org

“Indoor Air Quality Fact Sheet.” Agency for Toxic Substances and Disease Registry.

http://www.atsdr.cdc.gov/drywall/docs/IndoorAirQualityFactSheet.pdf

Other government agencies

U.S. Environmental Protection Agency

Indoor Environments Division
401 M Street, SW (6604J)
Washington DC 20460
202-233-9370
Indoor Air Quality Information Clearinghouse: 800-438-4318

http://www.epa.gov/iaq

National Asthma Education and Prevention Program

National Heart, Lung, and Blood Institute Information Center
P.O. Box 30105
Bethesda, MD 20824-0105
301-592-8573

http://www.nhlbi.nih.gov/about/naepp

National Institute of Environmental Health Sciences

National Institute of Health
P.O. Box 12233
Research Triangle Park, NC 27709
919-541-3345

http://www.niehs.nih.gov

Centers for Disease Control and Prevention

1600 Clifton Rd.
Atlanta, GA 30333
800-CDC-INFO
http://www.cdc.gov/mold/

Nonprofit organizations

American Lung Association

1740 Broadway
New York, NY 10019
800-LUNG-USA, or 212-315-8700

http://www.lungusa.org

Other websites

Environmental Law Institute’s Database of State Indoor Air Quality Laws

http://www.eli.org/Program_Areas/iaq_databases.cfm

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