Mosquitoes need standing water to lay their eggs in. Even a small pool of water can produce hundreds of mosquitoes that can transmit diseases like West Nile virus.

Here are some tips for homeowners from York Region Health Services:

• Drill holes in the bottom of garbage cans and recycling containers for drainage.
• Store pet bowls indoors when not in use.
• Clean roof gutters, downspouts and eaves troughs regularly.

Fighting Asthma in Your House | CMHC

Asthma is an inflammatory disorder of the airways. It is one of the most common chronic conditions affecting Canadians. Physicians have diagnosed more than 2.2 million Canadians as being asthmatic — 12.2 per cent of Canadian children and 6.3 per cent of adults — according to the 1996–97 National Population Health Survey.

Asthma is not only one of the most common chronic conditions among Canadians; it is growing rapidly among children. In 1996, physicians diagnosed four times as many children with asthma as they did in 1984.

Realty Times - Real Estate News and Advice

Health Canada is poised to tighten up guidelines for radon gas levels in indoor air, to a level four times more stringent than current guidelines. It could mean that radon testing will become mandatory in future real estate transactions, and that building codes for new homes will be upgraded. Critics say that Canada should have adopted the stricter guidelines in the 1980s, when the United States and other countries around the world set their radon guidelines. But Health Canada says that "until recently, there was no evidence providing a direct link between radon levels in the home and lung cancer." The ministry says that, "However, in 2005, two independent scientific studies performed in Europe and North America showed that lung cancer risks extend to levels of radon found in some homes depending on the length of time an individual is exposed to it." The Health Canada report estimates that lung cancers from radon exposure account for about 10 per cent of all lung cancers, second only behind smoking.

CMHC - Radon : A Guide for Canadian Homeowners