Indoor Air and Dampness, Mould

by Health Canada

Reduced natural ventilation, too much humidity, the use of chemicals and other factors can lead to unhealthy air in your home or workplace, causing a number of health problems such as respiratory symptoms and allergies.

On average, Canadians spend about 90 percent of their time indoors, so the quality of indoor air is very important. Humid or damp conditions in your home can encourage the growth of mould and dust mites. Unless you use a vacuum cleaner with high efficiency filters, floors, carpets and upholstery can build up mould spores, bacteria and sources of allergies.

Mould can develop from too much humidity, building leaks, refrigerator drip pans, bathroom surfaces and flooding. Mouldy smells from carpets, wood and gypsum board are a sign that they harbour fungi. Stale water in humidifiers and air conditioners can lead to the growth of bacteria and fungi. Air filters also collect dust and contaminants.

A major cause of poor indoor air quality is a lack of fresh air, that is, not enough exchange of air between the outside and inside. Where there is a lot of water vapor, such as in the bathroom, mechanical ventilation such as a fan may be needed eliminate excess humidity.

The Risks of Poor Air Quality

Contaminants often found in damp buildings are associated with a number of health problems, including diseases such as asthma or allergic rhinitis and non-specific symptomssuch as cough, wheezing and headaches.

Moulds are filamentous fungi that grow in damp environments. Mould spores contain allergens and irritants. People living in houses where moulds grow are more likely to suffer from asthma or respiratory symptoms.

Viruses can also be found indoors, but they don't survive long in the air. Viral infections usually result from contact with infected people.

Minimizing Your Risk

Improving indoor air quality is fairly simple. Here are several steps you can take.

• Control the humidity and let more air into your home to prevent moisture from building up on walls and windows. Where there is a lot of water vapor, such as in the bathroom, mechanical ventilation such as a fan may be needed eliminate excess humidity.
• Measure humidity using a hygrometer, to see if you need a dehumidifier. It is advisable to keep the relative humidity in your home below 50% in summer and 30% in winter
• Repair leaky roofs, walls and basements.
• Clean mouldy surfaces with a strong detergent
• Keep your home clean and dust-free.
• Regularly clean and disinfect humidifiers and air conditioners.

If you have severe humidity or contamination problems, ask your provincial or regional health department for advice. Check the sources listed below for more information on the problem. Talk to your doctor if you think anyone in your family suffers from health problems caused by poor air quality.

About the Author

www.hc-sc.gc.ca
Health Canada is the Federal department responsible for helping Canadians maintain and improve their health, while respecting individual choices and circumstances.