Do you sniffle and sneeze and wheeze your way through the year? If you are
plagued by allergies and/or asthma, you may be considering purchasing a home
air filtration system. But is it worth the money? Will it actually help ease
your symptoms? Not if you don't make other changes in your environment as well,
say medical experts.
"Buying an air cleaner is not my first suggestion," says Nathan
Rabinovitch, MD, assistant professor of pediatrics at National Jewish Medical
Research Center in Denver. "It's more of a backup
Minimize Exposure First
Instead, minimizing your exposure to other allergens in the home is the first
line of attack in reducing allergic and asthmatic reactions, says Rabinovitch,
who offers these suggestions:
Avoid carpeting and use
smooth flooring instead.
If you have pets, consider
finding them a new home. If that's not an option, keep the pets outside. If
that's not an option either, at the very least, keep them out of the bedroom,
and certainly off the bed, and off as much of the other furniture in the house
Use air conditioning in
the warmer months to get rid of outdoor pollens or allergens.
Clean all air filters, air
conditioner filters, and duct filters at each change of season.
Keep your windows closed
(at home and in the car) and avoid spending time outdoors when your allergies
are acting up.
Ban indoor smoking.
Use the hottest water
possible to rid your laundry of dust mites.
Avoid furnishings that
Seek an Air Filter Second
If you have tried these tactics and aren't finding adequate relief, then it may
be time to consider adding an air filter. Both the U.S. Environmental
Protection Agency (EPA) and the American Lung Association recommend air
filtration for people with allergies and asthma, but not as a solution by
itself. Controlling allergy-causing pollution and ventilation are more
important; there is disagreement on whether filters give much added relief from
asthma in a clean and well-ventilated home.
This opinion is echoed by the Institute of Medicine, which has said "air
cleaners are probably helpful in some situations in reducing allergy or asthma
symptoms," but that air cleaning "is not consistently and highly
effective in reducing symptoms."
But an air filter still might help you. There are five basic types:
Mechanical filters force air through a special screen that traps
particles including allergens like pollen, pet dander, and dust mites. They
also capture irritant particles such as tobacco smoke.
The best-known mechanical filter is the high-efficiency particulate air (HEPA)
filter. HEPA (which is a type of filter, not a brand name) was developed during
World War II to prevent radioactive particles from escaping from
To qualify as a true HEPA filter, a device must be able to capture at least 90%
of all particles 0.3 microns or larger in diameter that enter it. There are
filters on the market that claim to be HEPAs, but may not be as efficient, so
look for a system that meets true HEPA filtration standards.
Electronic filters use electrical charges to attract and deposit
allergens and irritants. If the device contains collecting plates, the
particles are captured within the system; otherwise, they stick to room
surfaces and have to be cleared away. The most efficient filters are
electrostatic precipitators, and the best of those use a fan.
Hybrid filters contain elements of both mechanical and electrostatic
Gas phase filters remove odors and non-particulate pollution such as
cooking gas, gasses emitted from paint or building materials, and perfume. They
do not remove allergens.
Ozone generators are devices that intentionally produce ozone, which
manufacturers claim cleans the air. They are not recommended by the EPA or the
American Lung Association because ozone can be harmful to lungs at high
concentrations. And the EPA says ozone at safe levels "have little
potential to remove indoor air contaminants."
Still, if you do choose to use such a device, the American Lung Association
advises "choosing one that ensures high efficiency over an extended period
of time (at least several months) and does not produce ozone levels above 0.05
parts per million, either intentionally or as a by-product of its
If your home is heated or air conditioned through ducts, it may be possible to
build filters into your air handling system. A whole-house system will
also save space and additional noise in your home. On the other hand, the
filters may be more expensive and more difficult to handle, and they may need
to be changed more often.
Choosing a Device
The Allergy and Asthma Foundation of America suggests asking these questions
before purchasing an air filter:
Do any of these scenarios sound familiar?
You catch a whiff of a co-worker's new fragrance, and within minutes, you
have a whopper of a headache.
You pop open that new bottle of dish-washing liquid, and by the time you've
washed the pots and pans, your hands and arms are covered in hives.
You walk into a friend's home and smell freshly baked pumpkin pie. Only
after you start sneezing uncontrollably and feeling dizzy, weak, and sick to
your stomach do you learn she hasn't been baking...
What substances will the
cleaner remove from the air in my home? What substances will it not?
What is the efficiency
rating of the cleaner in relation to the true HEPA standard?
Will the unit clean the
air in a room the size of my bedroom every four to six minutes?
What is the device's clean
air delivery rate (CADR)? The Association of Home Appliance Manufacturers rates
air cleaners according to their clean air delivery rates (CADR), which indicate
how much filtered air the cleaner delivers. There are different CADRs for
tobacco smoke, pollen, and dust. The higher the numbers, the faster the unit
How difficult is it to
change the filter? (Ask for a demonstration.) How often does it have to be
changed? How much do filters cost? Are they readily available throughout the
How much noise does the
unit make? Is it quiet enough to run while I sleep? (Turn it on and try it,
even though you will probably be in a store and may not get a true sense of
just how noisy it is.)
Those with lung conditions such as emphysema or COPD might also consider
buying an air filter, says Paul Enright, MD, research professor of medicine at
the University of Arizona. But if you're a healthy individual living in a
relatively unpolluted environment, there's no need to spend the money.
Just remember, Enright says, that an air cleaning system is just one of the
environmental changes you can make to alleviate symptoms. "There is no
single appropriate answer to coping with allergies and asthma."
SOURCES: CDC. Natural Resources Defense Council. Gary
Woodard, JD, MPP, assistant director for knowledge transfer, University of
Arizona. Charlie Hollis, president, Mirex Aquapure Solutions, Houston.
"Water-filtering systems," ConsumerReports. News release,
"Purefecta Drinking Water Purifier From Pall and Kinetico Protects 'At
Risk' Populations From Disease-Causing Organisms." "Drinking Water
Treatment Systems and Products," Fact Sheet, Robert Falls & Co. Public