Reducing Your Exposure to Mold

Molds are small organisms found almost everywhere, inside and outside, including on plants, foods and dry leaves. They can be nearly any color – white, orange, green or black. Molds are beneficial to the environment and are needed to break down dead material. Very tiny and lightweight, mold spores travel easily through the air.

Most building surfaces can provide nutrients to support the growth of mold. When mold spores land on material that is damp – for example, walls, floors, appliances (such as humidifiers or air conditioners), carpet or furniture – they can begin to multiply. When molds are present in large numbers, they may cause allergic symptoms similar to those caused by plant pollen.

What does mold need to grow?

Mold needs –

  • a food source such as leaves, paper, wood or dirt
  • a source of moisture
  • a place to grow

What are sources of moisture in my home?

Many sources can cause moisture in your home including –

  • flooding and sewer overflows
  • leaky roofs
  • humidifiers
  • damp basement or crawl spaces
  • constant plumbing leaks
  • clothes dryers vented indoors

How can I be exposed to mold?

We all are exposed to mold every day. When mold is growing on a surface, spores can be released into the air where they can be easily inhaled. A person who inhales a large number of spores may suffer adverse health effects.

What health effects can be caused by exposure to mold?

Some people are more sensitive to molds than others. These include –

  • infants and children
  • elderly persons
  • immune compromised persons (people with HIV infection, cancer, liver disease, etc., or who are undergoing chemotherapy)
  • individuals with existing respiratory conditions, such as asthma and allergies

The same amount of mold may cause health effects in one person, but not in another. Exposure to molds can cause allergic symptoms such as watery eyes, a runny nose, sneezing, nasal congestion, itching, coughing, wheezing, difficulty breathing, and headaches.

When airborne mold spores are present in large numbers, they can cause skin irritation, allergic reactions, asthma episodes, infections and other respiratory problems for people. Exposure to high spore levels can cause the development of an allergy to the mold. See the Illinois Department of Public Health’s (IDPH) fact sheet, “Mold and Your Health,” for more information about health effects.

Can my home be tested for mold?

If you can see or smell mold, testing is usually not necessary. It is likely that you have a moisture problem that needs to be fixed.

Testing for mold is very difficult and expensive. Homeowners must hire a contractor to test their homes. Testing cannot determine whether health effects will occur. Mold is normally found outdoors and levels fluctuate from day to day depending on the season. Due to these uncertainties, IDPH does not recommend testing in most cases.

What should I clean and what should I get rid of?

If the home has been flooded, remove all drywall to at least 12 inches above or around any water mark. Harder, non-porous materials such as glass, plastic, or metal can be kept after they are cleaned. Carpets and rugs that cannot be thoroughly dried and cleaned should be discarded and replaced. If the damaged area is small, you may be able to save the carpet by cleaning the area with a mild detergent. There also are professional home cleaning services that may be able to clean your carpets.

If flood water or sewer overflows are the cause of the moisture problem, infectious organisms also may be a hazard. For information see IDPH’s fact sheet, “Cleaning Up After Flood and Sewer Overflows.”

How can I clean moldy surfaces?

It is important to make sure that the source of moisture is fixed before the mold is cleaned up. If this is not done, the mold will grow again. How you clean up areas contaminated with mold depends on the surface where the mold is growing. A professional should be consulted if large areas (more than 30 square feet) are contaminated with mold. If the surface is non-porous (glass, plastic, varnished wood, tile, etc.), you can take the following steps:

  • The surfaces first need to be cleaned:
    • Use a non-ammonia soap or detergent in warm water and scrub the entire area affected by the mold. Use a stiff brush or cleaning pad on block walls or uneven surfaces.
    • Rinse clean with water.
    • Dry completely.

  • The next step, if desired, is to disinfect the surfaces to help kill any mold missed by the initial cleaning:
    • Ventilate the area before using a disinfectant.
    • Disinfect the area with a solution of water and bleach (no more than 1 cup of bleach per 1 gallon of water). Never mix bleach with ammonia; the vapors are hazardous. Straight bleach will not be more effective.
    • Let disinfecting areas air dry completely.

How can I reduce my exposure to the mold while cleaning it up?

During the cleanup of mold, many spores may be released into the air. To prevent health effects, there are several ways you can protect yourself while cleaning up the mold.

  • Anyone with a chronic illness, such as asthma or emphysema, or who are immune comprised, should not do the cleanup.

  • Do not allow bystanders to be present when you are doing the cleanup.

  • Wear rubber gloves and clothing that can be easily cleaned or discarded.

  • To prevent eye irritation, wear goggles that do not have ventilation holes.

  • Wear an N95 or HEPA respirator mask purchased from a hardware store to reduce the mold spores you breathe in.

  • Tightly cover the air return vent if there is one in the affected area.

  • Turn on an exhaust fan or place a fan in a window to blow air out of the affected room to the outside (make sure the air is blowing outside the home, not into another room).

  • Open windows in your house during and after the cleanup.

  • Work over short time spans and take breaks in a fresh air location.

  • Double bag materials before you remove them from the contaminated area.

Where can I get more information?

Illinois Department of Public Health
Division of Environmental Health
525 W. Jefferson St.
Springfield, IL 62761
TTY (hearing impaired use only) 800-547-0466

Additional References

Web Sites

U.S. Centers for Disease Control and Prevention

American Conference of Governmental Industrial Hygienists Inc.

American Industrial Hygienist Association

U.S. Environmental Protection Agency

idph online home
Environmental Health Home

Illinois Department of Public Health
535 West Jefferson Street
Springfield, Illinois 62761
Phone 217-782-4977
Fax 217-782-3987
TTY 800-547-0466
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