Facts Concerning Indoor Moulds And Their Health Effects


We have heard or seen on advertisements phrases like toxic mould or black mould! These phrases create fear, panic and confusion. People have spent thousands of dollars in mould remediation or disposed off household items including clothes because of mould contamination. Are these decisions always based on facts or fear? It is a difficult question to answer. The objective of this article is to provide some basic facts about mould and the associated health effects to help those concerned with mould make cost-effective decisions.

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 levels between 30-60%. When excessive moisture or water accumulates indoors, mould growth will often occur, particularly if the moisture problem remains unnoticed or un-addressed for more than 48 hours. The key to mould control is 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.

Why Be Concerned About Indoor Mould and Bacteria Growth?

Health Risk.
Mould pose health risks. As they grow indoors, moulds produce spores and/or chemical compounds into the air. The health effects associated 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.

Mould Contamination Can Affect Businesses.
Mould growth in the work place can affect the productivity of employees either directly or indirectly. A business affected by microbial contamination problems can soon see its market share fall and incur huge costs in liabilities. For example in food processing plants such as bakeries, bread can develop mould even before it leaves for the market.

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.

About the Author

Dr. Jackson Kung'u is a Microbiologist who has specialized in the field of mycology (the study of moulds and yeasts). Dr. Kung'u provides how-to advice and laboratory analytical services on indoor mould and bacteria to homeowners, environmental consultants, institutions and indoor air quality professionals across Canada. Get more information about indoor mould and bacteria at http://www.moldbacteria.com.