MOLD AND INDOOR AIR QUALITY

Mold is a fungus that is an often fuzzy-looking growth which appears on the surface of organic materials in damp conditions, both outdoors and indoors.  Molds feed off the moist organic material similar in ways that plants feed from the ground.  Molds have a variety of colors: gray, green, yellow, orange, black, etc.. and may have a velvety or wooly texture.

Molds reproduce by producing tiny spores that become airborne thus allowing them to propagate in other areas.  Mold spores continually waft through the air, both indoors and out-of-doors, these spores are so small that when inside a room with no air movement they will tend to stay airborne for as much as two weeks before settling.  Once they settle they will wait for a moisture episode (flood, leak, etc..) to occur.  When a moisture episode occurs, or if the mold spores land on a damp spot, they may begin growing and digesting whatever they have landed on in order to survive.  Indoors, molds can grow on wood, paper, fabrics, carpet, foods and other organic materials.

Molds are a natural part of the environment, but human health problems may result when people are exposed to large amounts of mold, particularly indoors.  To most people it is harmless and at worst a nuisance.  However, inhaling excessive quantities of airborne mold particles or spores may lead to allergic illness, trigger asthma, cause respiratory infections, or bring about toxic effects from certain chemicals in the mold cells.

Certain molds have even been found to have a positive (antibiotic) effect (e.g. Penicillin). However, some people can become sensitive (allergic) to specific molds and/or classes of fungi.  Clearly the most common type of exposure concern is for and among people who are asthmatic, allergic or prone to hypersensitivity pneumonitis since these individuals may react regardless of the amount of mold present. 

When excessive moisture, vapor or humidity accumulates indoors, mold growth will often follow, particularly if the moisture problem remains undiscovered or is not remediated promptly.  There is no practical way to eliminate all mold and mold spores indoors.  However, indoor mold growth can be (for the most part) prevented by controlling moisture.

Most Homes Have a Mold Problem. Even if your home looks clean, chances are good you've got mold, often at levels high enough to trigger allergy and asthma attacks. That bit of dour news comes courtesy of a new university research study that also found the mold is frequently in areas most people don't associate with it -- windowsills, for instance. After surveying 160 homes in seven U.S. cities, Kelly A. Reynolds of the University of Arizona, Tucson, found that 100 percent of the homes tested positive for mold on some inside surface. The discovered molds were all highly allergenic molds. Read the entire home moldresearch. "Up to one-third of [non-residential] buildings in industrialized countries are sick," according to the World Health Organization, 1995.    The Ottawa, Canada-based Canadian Mortgage and Housing Corporation (CMHC) warns in a pamphlet published at its web sitethat "if you live in a damp house, or have ever experienced flooding, your house may be breeding an often invisible and always unwelcome intruder - mold." Ken Ruest, Senior Researcher with the CMHC points out that, "a lot of people are unaware there's a toxic mold problem until their house is so badly affected they can't live in it anymore."

Mold fungi grows well in homes, condominiums, apartments, offices, and other work places and buildings because most property owners and managers do NOT properly maintain building roofs; exterior siding; windows; heating, ventilating, and air conditioning [HVAC] equipment and ducts; and plumbing fixtures, water lines, and sewer lines to prevent water intrusion, and/ or they fail to quickly find, detect, search for, and repair mold water plumbing problems such as water leaks, water and sewer breaks, broken water and sewer lines, dripping water, running water, flooding, flood damage, and other water, moisture, humidity, sewer, mold damage problems, black mold infestation, and toxic mold contamination.

ASSESSMENT

All that is needed for microbial growth to occur is a substrate, nutrients, warmth, and moisture.  Wood, paper, some carpets and carpet backings, wallboard and other building materials and furnishings act as both substrate and nutrient.  Substrates are surfaces that will trap nutrients such as dead skin cells, food crumbs, dust, dust mites, animal dander, dead insect parts and soil. This "dirt" can also contain the spores and "seeds" for such common microbiological contaminants as molds, fungi, mildews and bacteria. Sufficient moisture and adequate time for growth are often the final ingredients. Light is not always necessary and only moderate warmth (temperatures slightly above freezing) is required.  Fungi have been around for a long time and have become adapted to all types of environments and conditions.

After performing thousands of mold inspections, Envirotest has come to the conclusion that sampling indoor airborne mold using Anderson plate methods is the best techniques for sampling airborne mold. 

1. Envirotest’s microbiological air monitoring reports results appear as a number of Colony Forming Units (CFUs). CFUs are the number of live or growing colonies. Some sensitive individuals will react to the protein containing residue of mold and other biologicals that lie in the dust.
2. There are no standards against which sample results can be interpreted. However,  a list of the most commonly found molds and their exposure symptoms are included in the mold testing section of this website.
3. While there are a wide variety of sampling protocols and methods available to test for

microbiologicals, Envirotest depends on the Anderson sampling method, on-site visual assessments, bulk samples and wipe sample for testing. Environmental molds do not lend themselves to the more familiar "medical type" testing, since it depends upon culturing with standard methods and conditions. It must be known that the environment and the food that is available can change both the color and shape of the colonies. These are key to the identification of the mold. The same factors can also produce sterile or non-reproducing colonies. These also may be missed in testing that focuses upon "live spores" or "colony forming units".

4. As with all plants, the life cycle of molds varies with the season. It is not uncommon to have high levels of CFUs reported both indoors and outside during the growing season. The reproductivity of molds also varies from day to night.

RECOMMENDATIONS

Envirotest strongly recommends that mold removal be performed by a trained professional to decrease the chance of individual exposure and building contamination.

It is with all of the above in mind that, the following recommendations can be offered

1. Carpets, when present, should be subject to regular (daily) cleaning using one of the relatively new high efficiency (HEPA) vacuum cleaners. During this daily cleaning, look for water damage. Carpet should also be cleaned professionally on a periodic schedule (only between the months of November to February), or, whenever excessively soiled. Carpets must be thoroughly dried whenever professional cleaning is done. Basement sub-floors are not recommended as a base for carpeting due to the inherent buildup of moisture that can be caused and subsequent mold that can develop. Envirotest recommends a preference for solid surface materials or vinyl tile when carpet is to be replaced.

2) Attempt to identify areas of concern by visual inspection. Additional information can be gathered by professionally sampling the area(s) for the characteristic odors associated with mold. The ventilation system should also be examined in a similar way.

3) Eliminate all sources of water. All leaks should be fixed. Excessive humidity can often be removed and/or controlled with dehumidifiers.

4) Where mold contamination is suspected, many experts in the field feel it is simple and thorough enough to say "if you can see mold or smell mold: clean and/or decontaminate it." Cleaning and/or decontamination of surfaces can include any and all of the following:

     a) Wash solid surfaces and launder all fabric based materials, which may

          have been exposed, with bleach (if possible), hot water and detergent.

     b) Dry immediately and completely (exposure to strong sunlight is helpful

          during this process).

     c) Decontamination of white clothes is best done by using a bleach solution.

     d) Materials that can not successfully survive the above cleaning and/or

         decontamination should be replaced. However, the areas left behind

         should be decontaminated before replacement materials are installed.

         Areas of replacement, that then need painting, can best be painted with

         paints which have mold inhibitors included. This information is usually

         included on the label.

5) Any water damaged porous materials (e.g. ceiling tiles, carpet and wallboard) that cannot be dried out and cleaned within 48 to 72 hours should be removed and replaced. Bacteria and mold can begin to grow within this period of time.  

6) Should there be further problems consult Envirotest to perform sampling to determine exact mold types and air quality problems.