Asthma & Dust Mites

18 Jan

Asthma & Dust Mites

Asthma, an inflammatory disorder of the airways, is one of the most common chronic respiratory conditions affecting Canadians. Physicians have diagnosed more than 2.3 million Canadians as being asthmatic—8.4 per cent of adults (Statistics Canada, 2009) and 13.4 per cent of Canadian children (Garner, 2008).

While the exact cause of asthma is unknown, it appears to result from a complex interaction of predisposing factors (tendency to have allergies), causal factors that may sensitize the airways (such as animal dander, dust mites, mold, cockroaches and workplace contaminants) and contributing factors, such as tobacco smoke during pregnancy and childhood, respiratory infections and indoor and outdoor air quality (National Asthma Control Task Force, 2000).

Management of asthma involves the individual, his family and his physician. Asthma specialists recognize the importance of avoiding or controlling known environmental factors, or “triggers,” that aggravate asthma. Triggers include biological pollutants, such as mold, house dust mites and pollen, as well as irritating pollutants, such as nitrogen oxide, ozone and formaldehyde (Canadian Asthma Consensus Group, 1999). For some individuals, avoiding allergens (substances that produce allergic reactions) can be the most important element of asthma management. The National Asthma Control Task Force recommends a management plan that includes reduction of aeroallergens, molds, tobacco smoke, vehicle and industry emissions, noxious odours and scents that can trigger asthma episodes. The Canadian asthma consensus report, 1999 says that increasing medication should not be a substitute for avoiding exposure to allergens and irritants.

This article deals with reducing your exposure to causal and contributing factors in the home. It provides a global approach consistent with the recommendations of the National Asthma Control Task Force and the Canadian asthma consensus report, 1999. The recommendations are aimed at reducing exposure to allergens and other substances that are known to have a potential impact on respiratory health and indoor air quality.
When allergens are involved, elimination is preferable to reduction, since even very small amounts can provoke symptoms. Although evidence of an association between the development or worsening of asthma and some nonallergenic contaminants, such as volatile organic compounds (VOCs), is lacking, the Institute of Medicine (2000) suggests that it is prudent to limit exposure where practical.

The importance of thorough vacuuming House dust is a reservoir of dust mites, fungal glucans (cell wall components) and bacterial endotoxins. As exposure to these potential allergens occurs when house dust becomes airborne, it is important to reduce house dust as much as possible. A recent CMHC study demonstrated that this can be challenging. The study found that four to five successive vacuuming sessions with a High-Efficiency Particulate Air (HEPA) filter-equipped vacuum cleaner, at a rate of one minute per square metre for carpets and half a minute for non-carpeted areas, were required to significantly reduce the amount of fine dust in the homes tested.

Dust mites
Dust mites are microscopic bugs that live on pillows, mattresses, bedding, stuffed toys, upholstered furniture, fabrics and carpets. They feed on skin flakes from people and thrive in humid environments. They can trigger asthma symptoms and can cause asthma in children with no previous asthma symptoms (United States Environmental Protection Agency, 2008). Strategies to control dust mites include:

  • Reducing the relative humidity (RH) in your house to reduce dust mites and mold. Dust mites need RH above 55 per cent to grow. The most effective way to prevent the growth of dust mites is to reduce the RH of your house in the winter. The Canadian asthma consensus report, 1999 recommends humidity levels below 50 per cent.
  • Vacuuming thoroughly and often, since dust mites are a component of household dust. Use a vacuum cleaner with a HEPA filter or a central vacuum that exhausts to the outside.
  • Wearing an N95 respirator while vacuuming. Sensitive individuals and children should keep away from the immediate area. This will help reduce exposure to dust mites that become airborne with fine dust.
  • Properly maintaining furnace filters. This can reduce fine particles in your air distribution system that can be a home for dust mites. To further reduce the amount of dust circulated by your air distribution system, regularly vacuum as far as you can reach into air registers and return ducts. If you find that the return air ducts are dirty, or if the ducts have not been cleaned since the house was built or you moved in, have your ducts cleaned. Ensure that the contractor does not spray chemicals, such as fungicides, disinfectants or essential oils into the ducts.
  • Reducing the amount of particulates you bring into the house by taking off your shoes upon entry and using washable doormats.
  • Dusting with a HEPA vacuum or a damp cloth instead of dry dusting to help control dust (Canadian Partnership for Children’s Health & Environment, 2005).
  • Reducing the amount of upholstered furnishings and fabric coverings in your bedroom that can provide a home for dust mites.
  • Vacuuming upholstered furnishings with a HEPA vacuum while wearing an N95 respirator.
  • Avoiding carpets—they are good dust collectors that can hold dust mites.

Sleeping area strategies include:

  • Changing bedding frequently. n Washing bedding in warm water. Contrary to popular belief that hot water is needed to kill dust mites, a warm water wash with pre-soaking is effective at controlling dust mites (Vyszenski-Moher, Arlian & Neal, 2002).
  • Using washable linens such as cotton with small enough pore size (for example, 200 thread count). Washing bedding frequently is more important than encasing a mattress with a cover that cannot be removed easily for cleaning.
  • Vacuuming mattresses with a HEPA vacuum periodically.
  • Replacing pillows at least once a year.
  • Avoiding the use of “acaricides”— pesticides that kill dust mites.
  • Allowing bedding to dry by keeping beds uncovered when you get out of bed.

Mattress covers
Typical recommended measures for avoiding dust mites include encasing mattresses, box springs and possibly pillows with mite- and allergen-impermeable covers (Health Canada, 2007). Impermeable covers will protect new mattresses from infestation and keep mites already contained in older mattresses from passing through to the surface. However, everyday use leaves skin flakes on surfaces, on which dust mites feed. Exposure to dust mites can be reduced by frequently changing the bedding and vacuuming the mattress

Contact your REALTOR at Coldwell Banker Vantage Realty for more tips and advice on keeping you safe in your home.

Reference

Bibliography
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Canadian Partnership for Children’s Health & Environment. (2005). Child Health and the Environment— A Primer. Toronto, ON, Canada: CPCHE. Retrieved March 2009, from www.healthyenvironmentforkids.ca
Garner, R. & Kohen, D. (2008). Changes in the prevalence of asthma among Canadian children. Ottawa, ON, Canada: Statistics Canada. Retrieved May 2009, from http://www.statcan.gc.ca/bsolc/olc-cel/olc-cel?lang=eng&catno=82-003-X200800210551
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Institute of Medicine. (2000). Clearing the Air: Asthma and Indoor Air Exposures. Washington, DC: National Academic Press. Retrieved March 2009, from http://books.nap.edu/books/0309064961/html
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