Mould Contamination in Buildings
So what exactly is mould? Moulds are a fungus, which grow on various kinds of damp or decaying organic matter. Moulds and fungi are found everywhere in nature, and are necessary for the breakdown of leaves, wood and other plant debris. There are more than 100,000 species of mould in the world and 1,000 species which are common in Canada and the USA.
People are exposed to moulds through inhalation or skin contact. Touching mouldy surfaces can, in some cases, result in skin irritation. Moulds become airborne when materials are disturbed and spores are released into the air. Mould spores can be spread throughout buildings in ventilation systems using forced air. Central heating, ventilation and air conditioning (HVAC) systems that are poorly maintained are common sites for mould growth. Occupant activity like walking can spread mould spores throughout a building. Mites, which thrive on paper and dust, can carry mould.
Visual inspection is the normal method of identifying mould problems. Moulds will most often appear as dark spots, stains or patches. The presence of mould or fungi can be confirmed by dabbing a spot with chlorine bleach. If the colour changes or disappears, the stain is likely organic and probably mould.
Various air samplers and sticky surface samplers can be used for indoor air quality sampling to identify the species/genus of moulds present. Spore trap cassettes are the most common type of air samples collected. Laboratory staff can then determine spore counts for each mould species identified. This type of testing is normally done after a water damage claim to assist in establishing the extent of contamination within a building compared to outdoor background levels so an abatement protocol can be derived. It is also done to verify if the structure is rehabilitated and fit for occupancy following a mould abatement. Swab or tape lift samples are useful to identify the visible moulds found on surfaces. Culturable mould samples are also an option but can take longer for laboratories to analyze as time must be given for the moulds to grow within the culturable media they are collected on. Remediation is intended to return the spore count to background levels after the mould abatement is completed by a certified contractor. Air quality testing is also often performed in workplaces and public buildings such as schools, when the possibility of mould is identified.
Mould contamination in buildings continues to receive attention in the media and is a concern for homeowners, property managers, insurance companies, and restoration companies. Without proper use of an indoor moisture control system, black mould can start to grow in a building in as little as 48 hours after exposure to water.
Common symptoms of prolonged inhalation include aggravation of asthma, cough and nasal congestion, eye irritation, fatigue, difficulty concentrating and headaches, similar to non-toxic allergic reactions. Dr. Johanning proposes the name “fungal syndrome” for the ailments produced by indoor air exposure to mycotoxin and allergen producing fungi. In his 2001 publication “Clinical findings related to indoor fungal exposure-review of clinical data of a specialty clinic”, key messages reported include; “Many patients have a variety of symptoms, primarily the skin, mucous membrane, respiratory organs, central nervous system and constitutional symptoms” and “The prognosis appears good provided the exposure can be stopped”.
Mould contamination has been identified as a contributor to building-related illness and poor indoor air quality. Some moulds release mycotoxins, which can have adverse health effects for some people, particularly those with increases sensitivity to mould. Some moulds also release microbial volatile organic compounds (MVOC’s) which contribute to the musty odours often found with mould and can also contribute to health related symptoms.
A qualified mould professional should be retained by insurers to identify areas and causes of moisture within buildings that lead to mould growth. Prevention of mould growth is achieved by removal of moisture within the first 48 hours after exposure. If water is removed and materials are dried within that time period, then mould abatement is usually not necessary. We are happy to assist you on your next project.
