Asthma & Other Irritants
Asthma & Other Irritants
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.
Tobacco smoke
The most significant respiratory irritant is environmental tobacco smoke (ETS). Exposure to ETS is associated with increased frequency and severity of asthma and the development of asthma in predisposed infants and young children.
Volatile organic compounds
While other contaminants in the home have not been linked to asthma, they may act as respiratory irritants.
Nitrogen dioxide, gas stoves, wood smoke
A study found that women who used mainly gas for cooking reported higher asthma-like symptoms such as wheezing, waking with shortness of breath, asthma attacks and reduced lung function (Jarvis, Chinn, Luczynska & Burney, 1996). If you have a gas stove, install a range hood exhausted outdoors and use it when cooking.
Wood smoke is an irritant for people with asthma. If you are using a wood stove, ensure there is no backdrafting. If neighbours use wood-heating systems, you may have to make your house more airtight to prevent the smoke from entering your home.
Air purifiers
Ozone generators are not recommended (Health Canada, 2000), since ozone is an irritant that may aggravate asthma. Furthermore, ozone effectiveness in controlling mold and other pollutants is questionable.
Ozone can be produced as a by-product of negative ionizers and improperly wired electrostatic filters. Most portable air cleaners have a filter to remove particulates and a carbon filter (usually a cloth or membrane) to remove gases. The unit passes the room air through the filters to remove the pollutants. Several air purifiers have been shown to reduce the level of irritants in test chambers, but the health benefits have yet to be demonstrated consistently. The effectiveness of an air cleaner depends on several factors:
- The amount of air the unit can pull through. Small tabletop units have limited use in larger areas.
- The effectiveness of the filters. This refers not only to the appropriateness of the filter (a particulate filter will not remove a gaseous pollutant) but also to how much the filter is capable of removing before it is replaced. A carbon cloth or membrane can adsorb (hold) only so much gaseous contaminant, after which the filter will return removed contaminants to the air.
- The rate pollutants are being generated in the room or space. If there is a continuous source of pollutants, their production rate may be greater than the air purifier’s removal rate.
- The size of the room. A room air filter may have only a limited impact on the air in a large room with many pollutant sources. It may also have a limited impact in a small room that is well connected to the rest of the house by doors, ducts, leaks, etc., as pollutants will continue to move into the space.
The recommended approach is to find the sources of contaminants and remove or reduce them. A portable air purifier may be an option when source control is not possible.
Contact your REALTOR at Coldwell Banker Vantage Realty for more tips and advice on keeping you safe in your home.
Bibliography
Canadian Asthma Consensus Group. (1999). Canadian asthma consensus report, 1999. Canadian Medical Association Journal, 161, Supplement 11. Retrieved March 2009, from http://www.cmaj.ca/cgi/ reprint/161/11_suppl_1/s1
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
Health Canada. (2000). Air Cleaners Designed to Intentionally Generate Ozone (Ozone Generators)—Questions and Answers. Ottawa, ON, Canada: Health Canada. Retrieved March 2009, from http://www.hc-sc.gc.ca/cps-spc/house-domes/electron/cleaners-air-purificateurs-eng.php
Health Canada. (2007). Residential Indoor Air Quality Guidelines: Moulds. Ottawa, ON, Canada: Health Canada. Retrieved March 2009, from http://www.hc-sc.gc.ca/ewh-semt/pubs/air/mould-moisissure-eng.php
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
Jarvis D., Chinn S., Luczynska C., & Burney P. (1996). Association of respiratory symptoms and lung function in young adults with use of domestic gas appliances. Lancet, 347 (8999), 426-31.
National Asthma Control Task Force. (2000). The Prevention and Management of Asthma in Canada: A Major Challenge Now and in the Future. Ottawa, ON, Canada: Public Health Agency of Canada.Retrieved March 2009, from http://www.phac aspc.gc.ca/publicat/pma-pca00/About Your House
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