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MoldMolds produce tiny spores to reproduce. Mold spores waft through the indoor and outdoor air continually. When mold spores land on a damp spot indoors, they may begin growing and digesting whatever they are growing on in order to survive. There are molds that can grow on wood, paper, carpet, and foods. When excessive moisture or water accumulates indoors, mold growth will often occur, particularly if the moisture problem remains undiscovered or un-addressed. There is no practical way to eliminate all molds and mold spores in the indoor environment; the way to control indoor mold growth is to control moisture.

Ten Things You Should Know About Mold

  1. Potential health effects and symptoms associated with mold exposures include allergic reactions, asthma, and other respiratory complaints.
  2. There is no practical way to eliminate all mold and mold spores in the indoor environment; the way to control indoor mold growth is to control moisture.
  3. If mold is a problem in your home or school, you must clean up the mold and eliminate sources of moisture.
  4. Fix the source of the water problem or leak to prevent mold growth.
  5. Reduce indoor humidity (to 30-60% ) to decrease mold growth by: venting bathrooms, dryers, and other moisture-generating sources to the outside; using air conditioners and de-humidifiers; increasing ventilation; and using exhaust fans whenever cooking, dishwashing, and cleaning.
  6. Clean and dry any damp or wet building materials and furnishings within 24-48 hours to prevent mold growth.
  7. Clean mold off hard surfaces with water and detergent, and dry completely. Absorbent materials such as ceiling tiles, that are moldy, may need to be replaced.
  8. Prevent condensation: Reduce the potential for condensation on cold surfaces (i.e., windows, piping, exterior walls, roof, or floors) by adding insulation.
  9. In areas where there is a perpetual moisture problem, do not install carpeting (i.e., by drinking fountains, by classroom sinks, or on concrete floors with leaks or frequent condensation).
  10. Molds can be found almost anywhere; they can grow on virtually any substance, providing moisture is present. There are molds that can grow on wood, paper, carpet, and foods.

Where Do Molds Live?

  • Mold lives everywhere, especially in the soil outside
  • Molds can often be detected by a musty odor and discoloration of affected surfaces.

Health Effects

  • Eye, skin, nose, throat, and lung irritation
  • Long-term exposure may cause headaches.
    *Exposure to mold is common both inside and outside the home, but some people are more sensitive to mold exposure than others, especially those with allergies and asthma. Mold exposure may cause cold-like symptoms: watery eyes, sneezing, sore throat, wheezing, dizziness, and trigger asthma attacks.

Survival Needs for Mold

  • Nutrients
    • Mold can grow on material with a high cellulose and low nitrogen content.
    • Gypsum board
    • Paper
    • Leather
    • Dust
  • Temperature
    • Most fungi are mesophilic (15°-30° C - optimal growth range)
    • Some fungi are thermophilic (35°-50° C - optimal growth range)
  • Light
    • Fungi only grow in the dark is a myth (dark environments are often damp) and make for better growing conditions.
    • Some fungi need light to sporulate
    • Some can grow in darkness
    • UV light will NOT kill mold
  • Moisture
    • The key to controlling mold is to control moisture.
    • Since mold shares the same requirements for life as humans (e.g. nutrient sources, temperature, and light), moisture is the only factor we can control.
    • Water leaks, flooding, high relative humidity and condensation are all situations that increase the potential for mold growth.

How to Help Prevent Mold

  • Cleaning, disinfecting and drying surfaces help prevent mold growth. Mold will grow on damp surfaces within a couple days at normal temperatures.
  • Reduce moisture levels in the bathroom by running an exhaust fan during and after showers.
  • Fix plumbing leaks and seepage to prevent the buildup of moisture.
  • Store clothing dry and clean to prevent the growth of mold on clothes.
  • Reduce humidity levels by discontinuing use of a humidifier if the relative humidity is more than 40 percent, and use dehumidifiers and air conditioners when levels of humidity are high. Also, ventilate with outside air during the winter when outside temperatures are colder than indoor temperatures. Ventilating with summer air typically increases the air's relative humidity in a basement.
  • Increase the flow of air within your home. Moving furniture away from walls and opening closet doors to permit air circulation limits the growth of molds.
  • Prevent condensation. Insulating walls and installing storm or thermal pane windows keeps walls warm and limits condensation.

Basic Cleanup and Removal of Mold

  • Materials should be dried quickly; mold can grow within 24 to 48 hours.
  • Anyone spending more than a brief time cleaning in a moldy environment should use a HEPA filter mask.
  • Porous materials should be thrown out or decontaminated if they were wet more than a day. Materials such as hard plastic, glass and metal can be cleaned and disinfected.
  • Remove the mold using a non-ammonia soap or detergent. Never mix bleach and ammonia. Surfaces from which the mold cannot be removed should be treated with enough chlorine bleach to keep the surface moist for at least 15 minutes.
  • Rinse with clean water. Disinfect by applying a solution of ¼ cup bleach per gallon of water. The surface should be thoroughly wetted with the solution. Allow the solution to dry naturally for 6 to 8 hours.

    The EPA publication, "A Brief Guide to Mold, Moisture, and Your Home", is available here in HTML format. This Guide provides information and guidance for homeowners and renters on how to clean up residential mold problems and how to prevent mold growth.

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