• How Mold and Fungi Affect Indoor Air Quality
  • Mold

  • Where Can Mold be Found?

    Mold spores are found almost everywhere, both indoors and outdoors, and will grow wherever there is a source of moisture, a source of organic nutrition and an appropriate temperature.  These organisms are a vital part of the environment as they serve the important purpose of breaking down dead plant materials; however, when mold grows inside buildings, it can cause considerable damage. Public concern about exposure to mold increases as more people become aware of the negative health effects caused by exposure to mold in indoor environments.    

    Why is Mold a Problem?

    When mold consumes building materials it can produce certain chemicals, such as mycotoxins and microbial volatile organic compounds (MVOCs), some of which are toxic to humans. In addition to health concerns, mold growth in buildings can have extensive economic implications, if not handled quickly and appropriately.  

    Many building materials can be a food source for mold, which means mold colonization can spread rapidly though a building if mold spores infiltrate the space and encounter damp conditions. When mold grows on building materials, they digest the materials, destroy the surfaces and ultimately weaken underlying structures. Since mold spores are so common, it is imperative to control moisture and other indoor conditions both during the building process and after occupancy to prevent mold colonization from occurring.

    Sources of Mold

    Mold is a major indoor air concern. According to the Consumer Product Safety Commission (CSPC), surveys of large office buildings and homes in the northern United States and Canada show that 30 to 50 percent of them may have damp conditions, which may encourage the growth and build up of biological pollutants such as mold.

    Sources of indoor moisture that may cause mold problems:

    • Flooding
    • Backed-up sewers
    • Leaky roofs
    • Damp basement or crawl spaces
    • Constant plumbing leaks
    • Unseasoned firewood
    • Steam from cooking
    • Shower/bath steam and leaks
    • Wet clothes on indoor drying lines
    • Clothes dryers vented indoors
    • Combustion appliances not exhausted to the outdoors
    • Carpet directly on cement floors may absorb moisture and as a result encourage mold growth
    • Stagnant water that has accumulated in ducts, humidifiers, dehumidifiers and air-conditioners

    Building materials that support mold growth:

    • Paper
    • Gypsum board
    • Cardboard
    • Ceiling tiles
    • Wood
    • Dust
    • Paints
    • Wall coverings
    • Insulation
    • Drywall
    • Carpet
    • Carpet pads
    • Draperies
    • Fabric/upholstery

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