Pollution & air quality
Indoor air quality
Air cleaning devices
Here are some things to consider when you're thinking about getting a portable room air filtration device:
Try solving the air quality problem at its source
Before you buy any device, make sure you've done all you can to solve your air quality problem at its source. For example:
- The best way to get rid of cat allergens is to find a new home for the cat.
- The best way to get rid of strong chemical cleaner fumes is to switch to less volatile cleaners.
- The best way to reduce dust is to take steps to clean the bedding and room and vacuum often with a central vacuum system or HEPA-filtered vacuum (these vacuums won't release fine dust into the air)
When might an air filter help?
In areas where particles are present and cannot be otherwise eliminated, and people are particularly sensitive (for example, in the bedroom of a person with asthma), an air filtration unit with a HEPA filter may be a worthwhile addition. A filter with a charcoal component can also help in eliminating some gaseous odours.
Before you buy an air cleaning device, figure out what size of device is appropriate for your room, and where in the room it should be placed for maximum benefit. Putting the filter near the person affected may be more beneficial than having it farther away. Check the level of noise when the system is operating. Monitor the filter condition regularly and replace filters when necessary.
Buyer beware: before buying an air filtration device, consider the following:
- While there is a wide variety of technologies, there are no uniform rules or regulations about the performance, efficiency and effectiveness of air filtration devices.
- Many particles become trapped in furniture, drapery and clothing, and are not airborne (floating in the air) unless they are disturbed. For example, dust in your rug will be trapped there until you shake out or vacuum the rug. An air filter can only filter particles that are floating in the air- it can't filter particles that are trapped in objects.
- While there are some bona fide devices that do what they promise, other devices are ineffective and can be accompanied by unsubstantiated claims. Be especially cautious about products that promise 'health improvements'. While some products are effective in reducing the presence of triggers such as dust and pollen, there is no published evidence that health status will improve.
- Air filters designed to filter a single room do not perform well when there is central air circulation constantly exchanging the air in the room with the rest of the home. Isolating the room may yield lower particle counts, but remember to allow for some fresh air too.
- Deal with a reputable vendor. The Lung Association has received calls from consumers who feel pressured by some door-to-door vendors who offer to take a 'sample' of air for testing purposes and then suggest an expensive filtration device. Find out what performance and refund guarantees come with the product. When dealing with a vendor for the first time, it's always a good idea to check with your local Better Business Bureau and/or review products in Consumer Reports, the magazine and website of the independent, non-profit organization, Consumers Union.
Can air filters get rid of second-hand smoke?
No. There is no filtration or ventilation system that can effectively remove second-hand smoke (environmental tobacco smoke). Second-hand smoke has more than 4700 compounds in it. The only sure way to protect yourself from the harmful effects of second-hand smoke is to make sure no one smokes indoors.
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Caution about ozone generators
Be extra cautious about the purchase of ozone generators. While these devices have some commercial applications, they should not be used in residential settings (homes) where people are present. Ozone, a key ingredient in smog, can irritate your lungs and breathing. Generating ozone indoors where people are exposed is potentially harmful to health. Here's what other expert bodies have to say about ozone generators:
Caution about ionizers
Some ionizers are marketed with claims that they are beneficial for people with asthma. The Lung Association has seen no published scientific evidence of this. Based on current evidence, we do not recommend room air ionizers to reduce symptoms in patients with chronic asthma. Consumer Reports (May 2005) advises that many ionizing air cleaners do a poor job of removing airborne particles and can produce ozone as a by-product.
Caution about medical devices
Some air filtration devices may be marketed as medical devices. Consumers should know that The Lung Association does not accept the validity of Health Canada's Medical Devices designation as it relates to air filtration devices.
What about getting heating ducts cleaned? Will that improve air quality?
While some consumers have found duct cleaning effective, others have reported little, if any, improvement. It is recommended however in new and recently renovated homes, where construction particles may have settled into the ductwork. Otherwise, you can do some basic cleaning yourself by vacuuming the heating vents and cold-air returns gently as far inside as you can reach. If you feel the entire system needs cleaning, hire a reputable company. Be careful about allowing a chemical to be sprayed inside, as it may contribute to indoor air pollution within the home and could cause adverse reactions for hypersensitive individuals. Check with the vendor!
In between cleanings, ductwork can be protected from dust build-up by the installation and regular changing of a competent dust filter on the return air side of the furnace.
For more information on air cleaning devices (air filters, air purifiers, etc.)
People often ask the Lung Association about air cleaning devices; the information above answers many common questions. For more information on air cleaning devices and air quality, you can also consult:
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