Controlling Mold GrowthIntroductionMolds and fungi are found everywhere inside and outside. They can grow on almost any substance when moisture is present. Molds when they reproduce make spores, which can be carried by air currents. When these spores land on a moist surface that is suitable for life, they begin to grow. Molds are essential to the natural breakdown of organic materials in the environment. Without molds we would be inundated with dead organic matter. It has been estimated that 40 percent of United States homes have some form of mold problem.[1] Mold is normally found indoors at levels that do not affect most healthy individuals. When these levels become abnormally high as determined by indoor air quality testing or a mold inspection, remediation is recommended to be carried out by a professional remediation company. Health effectsThe problems with mold usually stem from the symptoms and health effects resulting from indoor mold exposure. There is public awareness that exposure to mold can cause adverse health effects, symptoms, and possible allergic reactions. Health professionals are often tasked with the investigation and/or assessment of these health effects on employees and/or the public. The most common form of hypersensitivity is caused by the direct exposure to inhaled mold spores or hyphal fragments which can lead to allergic asthma or allergic rhinitis.[2] The most common effects are runny nose, watery eyes, coughing and asthma attacks. Another form of hypersensitivity is hypersensitivity pneumonitis (HP). This is usually the direct result of inhaled large spores or fragments in an occupational setting.[2] About 5% of individuals are predicted to have some allergic airway symptoms from molds over their lifetime.[3] Toxic effects from mold are produced by exposure to the mycotoxins of some mold species, such as Stachybotrys chartarum (S. chartarum). These are often referred to as “Toxic molds” These toxic molds are often implicated as a potential cause of Sick Building Syndrome. A 1993-94 case study based on cases of pulmonary hemorrhage in infants in Cleveland, Ohio originally concluded there was no causal relationship between the exposure and the disease. The investigators revisited the cases and established a link to the exposure to S. chartrum and the infants in their homes. This relationship was later disproved by a different panel and re-evaluation.[3] Causes / Growing conditionsBecause common building materials are capable of sustaining mold growth, and mold spores are ubiquitous, mold growth in an indoor environment is typically related to an indoor water or moisture problem. Leaky roofs, building maintenance problems, or indoor plumbing problems can lead to mold growth inside homes, schools, or office buildings. Another common source of mold growth is flooding. For significant mold growth to occur, there must be a source of water (which could be invisible humidity), a source of food, and a substrate capable of sustaining growth. Common building materials, such as plywood, drywall, furring strips, carpets, and carpet padding are food for molds. In carpet, invisible dust is the food source (see also dust mites). After a single incident of water damage occurs in a building, molds grow inside walls and then become dormant until a subsequent incident of high humidity; this illustrates how mold can appear to be a sudden problem, long after a previous flood or water incident that did not produce a mold-related problem. The right conditions re-activate mold. Studies also show that mycotoxin levels are perceptibly higher in buildings that have once had a water incident (source CMHC). 
Both our indoor and outdoor environment have mold spores present. There is no such thing as a mold free environment in the Earth's biosphere. Spores need three things to grow into mold:
Mold colonies can grow inside building structures. The main problem with the presence of mold in buildings is the inhalation of mycotoxins. Molds may produce an identifiable smell. Growth is fostered by moisture. After a flood or major leak, mycotoxin levels are higher in the building even after it has dried out (source: CMHC). Food sources for molds in buildings include cellulose-based materials, such as wood, cardboard, and the paper facing on both sides of drywall, and all other kinds of organic matter, such as soap, dust and fabrics. Carpet contains dust made of organic matter such as skin cells. If a house has mold, the moisture may be from the basement or crawl space, a leaking roof, or a leak in plumbing pipes behind the walls. Insufficient ventilation can further enable moisture build-up. The more people in a space, the more humidity builds up. This is from normal breathing and perspiring. Visible mold colonies may form where ventilation is poorest, and on perimeter walls, because they are coolest, thus closest to the dew point. If there are mold problems in a house only during certain times of the year, then it is probably either too air-tight, or too drafty. Mold problems occur in airtight homes more frequently in the warmer months (when humidity reaches high levels inside the house, and moisture is trapped), and occur in drafty homes more frequently in the colder months (when warm air escapes from the living area into unconditioned space, and condenses). If a house is humidified artificially during the winter, this can create conditions favorable to mold. Moving air may prevent mold from growing since it has the same desiccating effect as lowering humidity. Keeping indoor air temperature higher than 74 degrees also has an inhibiting effect on mold growth. AssessmentThe first step in an assessment is to determine if mold is present. This is done by visually examining the premises. If mold is growing and visible this helps determine the level of remediation that is necessary. If mold is actively growing and is visibly confirmed the need for sampling for specific species of mold is unnecessary.[4] Another assessment method is to determine if the premise smells of mold, often described as an earthy or musty odor. However, not all molds produce the telltale mold odors. These methods are considered to be non-intrusive and only visible and odor causing molds will be found. Sometimes more intrusive methods are needed to assess the level of mold contamination. This would include moving furniture, lifting and/or removing carpets, checking behind wallpaper or paneling, checking in ventilation duct work, opening and exposing wall cavities, etc. Careful detailed visual inspection and recognition of moldy odors should be used to find problems needing correction. Efforts should focus on areas where there are signs of liquid moisture or water vapor (humidity) or where moisture problems are suspected. The investigation goals should be to locate indoor mold growth to determine how to correct the moisture problem and remove contamination safely and effectively. The basic goals of any mold investigation are always twofold: 1) find the locations of mold growth, and 2) determine the sources of the moisture. If these can be answered by simpler or more cost-effective methods, mold testing is probably not a wise use of resources. The key to mold control is moisture control. It is important to dry water damaged areas and items within 24-48 hours to prevent mold growth. If mold is a problem in your home, clean up the mold and get rid of the excess water or moisture. Fix leaky plumbing or other sources of water. Wash mold off hard surfaces with detergent and water, and dry completely. Absorbent materials (such as ceiling tiles & carpet) that become moldy may have to be replaced. Mold Inspections should be performed by a party certified as a Council-certified Indoor Environmentalist or Council-certified Microbial Investigator by the American Indoor Air Quality Council. In the state of Texas there is legislation dictating who can and cannot perform investigation. There are several other organizations who claim to certify, however the IAQ Council is the CESB standard for the mold practice. Cleaning and RemediationThe only proper way to clean mold is to use detergent solutions that physically remove mold. Many commercially available detergents marketed for mold clean-up also include an anti-fungal agent. Improper methods for cleaning mold include exposure to high heat, dry air, sunlight (particularly UV light), ozone, and application of fungicides. The goal of remediation is to remove or clean contaminated materials in a way that prevents the emission of fungi and dust contaminated with fungi from leaving a work area and entering an occupied or non-abatement area, while protecting the health of workers performing the abatement. [5] Four steps of professional mold remediation
Cleanup and removal methodsThe purpose of the clean-up process is to eliminate the mold and fungal growth and to remove contaminated materials. As a general rule, simply killing the mold with a biocide is not enough. The mold must be removed since the chemicals and proteins, which cause a reaction in humans, are still present even in dead mold. VacuumWet vacuum cleaners are designed to remove water from floors, carpets and other hard surfaces where water has accumulated. Wet vacuuming should only be used on wet materials, as spores may be exhausted into the indoor environment if insufficient liquid is present. After use this equipment must be thoroughly cleaned and dried as spores can adhere to the inner surfaces of the tank, hoses, and other attachments. Damp wipeDamp wipe is the removal of mold from non-porous surfaces by wiping or scrubbing with water and a detergent. Care must be exercised to make sure the material is allowed to quickly dry to discourage any further mold growth. HEPA vacuumHigh Efficiency Particulate Air filtered vacuum cleaners are used in the final cleanup of remediation areas after materials have been thoroughly dried and all contaminated materials have been removed. HEPA vacuum cleaners are recommended for the cleanup of the outside areas surrounding the remediation area. During this process the workers wear proper personal protective equipment (PPE) to prevent exposure to mold and other contaminants. The collected debris and dust should be stored in impervious bags or containers in a manner to prevent any release of debris. Disposal of debris and damaged materialsBuilding materials and furnishings contaminated with mold should be placed into impervious bags or closed containers while in the remediation area. These materials can usually be discarded as regular construction waste. EquipmentSeveral types of equipment may be used in the remediation process and may include:
Ancient Methods of Mold RemediationMold growth in buildings has been recognized as a health hazard since the earliest days of recorded history. The ancient Israelites, for example, had written procedures for purifying and inspecting buildings that were contaminated with mold. These procedures included removing contaminated bricks and disposing them in a dump. In extreme cases, the entire building was demolished and the refuse similarly disposed of in a dump. See Leviticus 14:33-14:53 Notes
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This article is licensed under the GNU Free Documentation License. It uses material from Wikipedia Encyclopedia article "Mold Growth, Assessment, and Remediation" |
