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Mould Growth In Buildings

Mould growth only occurs in moisture-damaged and damp building materials. The main causes of mould growth in buildings, therefore, may include poor maintenance and lifestyles of occupants, defective construction and use of building materials susceptible to mould attack. It is estimated that up to 40% and 30% of buildings in the USA and Canada respectively have mould problems.

Health Effects Associated With Mould Growth And Dampness

Several studies suggest that people living and working in damp or mouldy buildings have a higher risk of respiratory health problems such as asthma and bronchitis. Other symptoms associated with mould growth and dampness include blocked nose, itching eyes, and skin irritation. In agricultural environments, where the concentration of spores is several magnitudes higher than in indoor air, inhalation of spores has been associated with cancer, premature birth and farmers lung disease.

Dampness, Mould, Mites and Allergy

Dampness in buildings is believed to increase asthma and allergy risks. Studies have shown that the risk of asthma, allergic rhinitis, and atopic dermatitis is higher in damp homes. This is partly because dampness encourages proliferation of micro-organisms such as moulds, bacteria and mites, some of which are well established and documented toxin producers or allergens. Dampness in homes and workplaces should therefore be controlled in order to reduce the risk of occupants developing respiratory problems.

Mold in Homes Doubles Risk of Asthma

Exposure to dampness and mold in homes as much as doubles the risk of asthma development in children, according to a study published today in the March issue of the peer-reviewed journal Environmental Health Perspectives (EHP). Researchers studied 1,984 Finnish children aged 1 to 7 years over a six-year period to see if they developed asthma. Data collection included a baseline survey administered in March 1991, as well as a follow-up survey in March 1997, asking questions about the child’s health, parents’ health, parent’s highest education level, and details of the child’s environment including exposure to environmental tobacco smoke and presence of feathery or furry pets.

The study focused particularly on four indicators or moisture or mold in homes, including mold odor, visible mold, visible moisture, and history of water damage. The presence of mold odor proved to be the only significant indicator of asthma development.

A a total of 138 children, or 7.2% of the study population, developed asthma during the study period. Having a parent with a history of allergies increased susceptibility in children. Mold odor increased the risk, the study found, independent of parents’ medical histories. In fact, children living in homes with mold odor during the initial study period were more than twice as likely to develop asthma in the following 6 years.

“These findings strengthen evidence that exposure to molds increases the risk of developing asthma in childhood,” says lead author Jouni Jaakkola, director of the University of Birmingham’s Institute for Occupational and Environmental Medicine. “They also show the importance of heredity-children of parents with asthma have a two-fold risk of asthma compared with children of nonasthmatic parents.”

Children who were exposed to moisture or mold in homes were also slightly more likely to be exposed to environmental tobacco smoke, to have feathery or furry pets, and to have parents with a lower education level. The study adds to the body of evidence linking asthma with exposure to cigarette smoke.

“This study is important for families everywhere,” says Dr. Jim Burkhart, science editor for EHP. “Anyone with young children in the home should be aware of the potentially harmful effects of long-term exposure to mold and this potential link to asthma in children.”

In addition to Jaakkola, contributing authors included Bing-Fang Hwang of the Environmental Epidemiology Unit at the University of Helsinki in Finland, and Niina Jaakkola of the Department of Health Care Administration at Diwan College of Management in Taiwan.

Funding sources for the research as reported by the authors included the Ministry of the Environment, the National Agency for Welfare and Health, the Medical Research Council of the Academy of Finland, and The Yrjö Jahnsson Foundation.

EHP is published by the National Institute of Environmental Health Sciences, part of the U.S. Department of Health and Human Services. EHP is an Open Access journal. More information is available online at http://www.ehponline.org.

Environmental Health Perspectives (NIEHS)
PO Box 12233, MD EC-15
Research Triangle Park, NC 27709-2233
USA
Phone 919-541-2359
niehs.nih.gov/drcpt/ehpb/home.htm

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Mould in Your Home Or Office: What You Should Know

As you read this article there could be some mould growing silently somewhere in your house or in the office where you work. This thought may not have bothered you if you had not heard in the media phrases like “toxic mould” or “black mould”! These phrases create fear, panic and confusion. The objective of this article is to provide the reader with some basic facts about mould and the associated health effects.

Should One Be Concerned About Indoor Mould Growth?

Yes. Apart from mould being unsightly in a building there are 3 good reasons why people should be concerned about mould growth.

Health Risk

As mould grows indoors, it produces spores and/or chemical compounds that easily become airborne. The health effects associated with inhaling or getting into contact with these spores and chemicals may include runny nose, eye irritation, cough, congestion, aggravation of asthma and respiratory problems, headache, flu-like symptoms, fatigue, skin rash and other allergic reactions. Individuals with weak immune systems may also get infected by certain moulds as a result of exposure.

Legal Issues

Those responsible for building maintenance or health and safety of building occupants, contractors and other professionals involved in the building operations are at risk of being sued if occupants get sick from mould growth.

Material Damage and Impairment of Processes

Mould if allowed to grow, can impair the functioning of many processes from air conditioning units to electrical circuits. Surfaces of materials on which mould is growing get stained or discoloured and may disintegrate over time. Wood-rotting moulds are capable of weakening wooden structures.

Three Things You Should Know About Mould

  • Mould growth is a fact of life for almost all industrial and indoor environments. However, mould growth can be controlled by providing adequate ventilation and maintaining indoor humidity at levels below 65%. When excessive moisture or water accumulates indoors, mould growth will often occur, particularly if the moisture problem remains unnoticed or unaddressed for more than 48 hours. The key to mould control is keeping the building dry and clean, timely maintenance and prompt repairs.
  • Not all moulds are harmful but to be safe it is better to treat all moulds as potentially harmful. The colour of the mould does not determine whether it is harmful or not. Therefore, black mould is not necessarily bad mould. Mould related health effects depend on:
    • types of mould present,
    • amount of mould one is exposed to and for how long,
    • individual health status or sensitivity. Children, elderly and sick people are more vulnerable to mould.
  • It is difficult to eliminate all mould spores in the indoor environment. However, the levels can be minimised by controlling growth. Monitor mould growth by looking for water stains or discoloration on the ceiling, walls, baseboards, floors, and window sills. Pay particular attention to the basement and the attic.

What Should You Do When You Find Mould?

If you are an indoor mould consultant

  • Assess the extent of the mould problem.
  • Discuss the problem with your client and reassure them.
  • Have the dominant moulds identified preferably to species level. However, before sampling, prepare a sampling plan that details how and when samples
    would be collected, the type of samples to collect, collection requirements for each type of samples, the criteria to use to interpret results, and the benefits expected from sampling, i.e., what question(s) would be answered by the laboratory results and what actions would be taken. Share the sampling plan with the client.
  • Discuss the lab results with the client. If the client is concerned about their health, advise them to seek medical opinion from their family doctors.
  • Discuss the remediation plan (or options if any), the remediation costs and the expected results with your client.

If you Are a Property Manager or Homeowner

  • Do not panic! The presence of mould does not necessarily mean that you or the building occupants could have adverse health effects or that they have even been exposed.
  • Do not disturb the mould since this could help the mould in shedding more spores into the air.
  • If what you suspect to be mould covers more than 10 square feet, seek the advice of a qualified consultant immediately. If unsure of how to handle mould covering less than 10 square feet, seek professional advice. Avoid exposing yourself or others to mould.
  • Ask for the mould to be identified to reassure yourself or the building occupants that it is not among those that cause serious health effects.
  • Discuss the problem with your family doctor or if you are the property manager reassure the occupants and let them know the actions you are taking.
  • If you find a professional who seem to concentrate more on how the mould could or have affected you or the building occupants, seek a second opinion. A good professional should provide facts and avoid causing fear.

 

Should you have a question concerning indoor moulds, please send your question to My Question.

Alternaria And Other Mould Spores As Causes Of Allergy

As far back as 1924 Prof Dr Willem Storm van Leeuwen from The Netherlands suggested that inhaled mould spores such as those of Alternaria could cause asthma. The types of moulds widely known to cause respiratory allergy in humans include Aspergillus, Penicillium, Cladosporium and Alternaria. The allergic responses are mainly due to the inhalation of spores rather than mycelial/hyphal fragments. Allergic reactions to each spore type differ between individuals. Mould allergens also vary in the severity of the allergic reactions they induce. More people, for example, are more sensitive to Alternaria than to Cladosporium. Alternaria also produces more severe reactions, while Cladosporium generally only produces a mild reaction. Cladosporium and in particular Cladosporium herbarum, are often the major contributors to outdoor air-spora. Due to their high concentrations they are a major cause of inhalant allergy and allergic asthma in humans. Occupational pulmonary diseases are common in cheese industry (Penicillium roquefortii), breweries (Aspergillus clavatus) and in mushroom farms (Doratomyces sp).

Alternaria is cosmopolitan and ubiquitous in nature. It is currently comprised of about 40-50 species. Alternaria is a well recognized plant disease causing agent. Species of Alternaria are commonly isolated from dead plant materials, soil, food, and indoor air. Alternaria alternata has been isolated from numerous kinds of organic materials in damp situations, including textiles, stored food, canvas, cardboard and paper, electric cables, polyurethane, jet fuel, sewage and effluents. Airborne spores of Altenaria alternata and A. tenuissima are found in very high numbers in the outdoor environment during fall.

Spores of Alternaria alternata as seen under a microscopeAlternaria alternata is a well recognized allergen with airborne spores and mycelial fragments being responsible for the allergic symptoms in individuals with rhinitis or bronchial asthma. Alternaria sensitivity can also lead to severe and potentially fatal asthma. Studies have shown that up to 70 % of mould-allergic patients have skin test reactivity to Alternaria. It has also been shown that prolonged heavy exposure to Alternaria alternata spores and mycelial fragments mimics that of other allergens such as cat dander and dust mites. Since Alternaria is a seasonal mould then this type of allergy is more prevalent in the fall. A. alternata has also been recorded as an opportunistic pathogen causing skin diseases particularly in immunocompromised patients such as the bone marrow transplant patients.

The presence of Alternaria together with other moulds such as Ulocladium spp and Phoma spp, in indoor environment is indicative of humid conditions. Alternaria alternata is not commonly isolated from indoor building materials and in most instances spores found in indoor air environment may have originated from outdoor sources. A closely related mould, Ulocladium chartarum, which is very common in indoor environment is frequently misidentified in labs as Alternaria alternata. U. chartarum is common on wallpaper and drywall, and has been isolated from emulsion paint, polyurethane, plywood and manila fibre.

Should you have a question on Alternaria or any other mould, please send it to My Question.

Salmonella food poisoning and symptoms

Salmonella food poisoning has been a growing concern in recent news. It has frequently lead to recalls of beef, salads and organic products and, even peanut butter products. Salmonella food poisoning occurs when one eats raw or undercooked foods such meat, poultry, eggs or egg products. Properly cooked food can get contaminated with Salmonella if […]

Legionella pneumophila – Guidelines for Laboratory Interpretation

Legionella pneumophila is a Gram negative, aerobic bacteria that is characterized as an opportunistic pathogen. It is the cause of Legionnaires’ Disease, a severe form of pneumonia and, it is the cause of Pontiac fever, a non-pneumonic form of L. pneumophila infection. Legionella spp.’s mode of transmission is through aerosols or aspiration of contaminated water. The Public Health […]

The Indoor Mold Is An Early Warning Device

The mold (or mould, in the Queen’s English) has been the victim of a bad press. Mention the word and it conjures up an image of something rotting or in the process of decomposition. And yet, were it not for the mold that inspired the discovery of penicillin millions of lives would have been lost. […]