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Indoor air quality has become one of the major concerns of the Environmental Protection Agency. They say that the air inside homes and offices is more toxic than the worst outdoor air pollution, possibly two to five times worse, especially in newer, energy efficient houses. With insulating properties designed to keep winter's cold air out and summer's air conditioning in, the traditional exchange of indoor/outdoor air doesn't happen often enough in today's houses to keep interior air safe to breathe.
The result is lower utility bills and higher health costs. Allergies are on the rise. One study determined that 54% of our body's energy comes from the oxygen we breathe, so stale air indoors -- where most of us spend 90% of our time -- depletes our physical resources on every level while it attacks our immune systems with an overload of used air, resident dust mites, pet dander, mold spores and bacteria.
The traditional solution of "opening a window" isn't always possible (as in office buildings with stationary windows) or wise (for allergy sufferers in high-pollen seasons or on days of heavy smog).
More and more of us depend upon air filtration and purification systems to correct the problem. We can choose from a mind-boggling assortment of options in a wide price range to improve the quality of the air we breathe. No one filter or purification system can meet all needs, so it's important to know what your specific needs are before you go shopping for an air cleaning system for your home or office.
PERMANENT INSTALLATION
A filtration system installed on the furnace and/or central air conditioning system reaches most areas in most homes. The filters must be changed frequently, and if a combination humidifier/filter, the homeowner must pay special attention to cleaning the water supply so that mold does not grow and end up being disbursed throughout the house.
When considering an investment in a whole-house air cleaning system, shop carefully. Some are not as effective as some of the portable units, and, depending on the size of your house and the needs of your family, cost isn't always a reliable guideline.
PORTABLE UNITS
Portable systems meet the needs of renters and travelers. They are rated according to the amount of space they affect. When choosing a portable unit, remember that it will only clean air that actually passes through it. In order to be truly helpful, they should create enough air flow to exchange the air in that space five or six times an hour.
DIFFERENT PROCESSES
The type of filtration or purification process should be chosen based upon the kind of contaminants in the specific home. In wet climates, select a system that will destroy mold spores. For a home with children, a method of purification that kills most bacteria or viruses would be a wise choice. Allergy sufferers need to focus on a unit that will collect or destroy pet dander, pollen, dust mites, mold spores, mildew, tobacco smoke, or whatever triggers their specific reactions.
Persons with breathing problems from a lung deficiency will want to avoid adding anything to the air (fragrances or ozone gas) that would increase their health problems.
Fumes and virus microns are too small to be captured by any filtration device; ozone and negative ions have some effect on them. They are destroyed by ultraviolet light.
PROS AND CONS
• Ionizers: This is a process used in conjunction with other kinds of filters. It emits a small electric charge to the air stream which draws air through it; this creates a magnetic-like attraction for pollution particles and causes them to adhere to the filter.
• Electrostatic precipitators: Filters the air by creating opposite charges on metal wires or plates; this attracts and holds dust, pollen, smoke and other particles as small as .0001 microns on a metal, glass or fiberglass assembly that can be washed and re-used.
• Ultraviolet light purification: Passes the air through a UV system that destroys bacteria, viruses, and dust mites of any size.
• Ozone releasing: Destroys all bacteria that comes in contact with the ozone, and leaves a "fresh" smell in the air. We associate this with the clean smell following rain, because some ozone, carried from the outer atmosphere where it protects us from harmful sun rays, remains in the lower atmosphere after a storm.
The safety of ozone gas in interiors, however, is questionable; it can irritate the lining of lungs and exacerbate breathing problems. The US federal government has set standards depending on the rate of filtration and room size recommendations. The Canadian government has banned the sale of ozone releasing air purification systems.
• High efficiency particulate air (hepa) cleaners capture airborne pollutants .3 microns or larger; this includes some tobacco smoke, household dust, and pollens. The are designed to remove 99.97% of the particulates that pass through the filters, which cannot be cleaned and re-used; they must be replaced. They have no effect on fumes, viruses, bacteria, smaller mold spores, and some tobacco particulates.
• Ultra hepa: A more efficient version of the hepa, the makers of these filters claim that they remove out 99.999% of the particulates that pass through them.
COST
The initial cost of an air cleaner should not be the only budget criteria. While some systems carry a high purchase price, they may use less electricity to operate, and they may have a washable mechanism or use inexpensive replaceable filters. Some hepa products require filters that cost upwards of $100 each, and which must be replaced two to three times a year.
CERTIFICATION
Although it's far from universal use, the AHAM has established a rating for Clean Air Delivery Rate (CADR) whereby, after extensive independent testing, it certifies the performance of air cleaners according to efficiency and recommended room size.
The Federal Trade Commission and the Environmental Protection Agency have reviewed the testing process and agree that it provides a reasonable basis for judging performance. If a unit has been tested and rated by the AHAM, its test results and recommendations will be on the packaging.
FINAL NOTE
Nature is an age-old self-cleaning process. Whenever possible, open a window in a room being cleaned to air it out. Keep a fan going, pull back window coverings, and allow an ample exchange between the indoors and the outdoors.
Letting interior air out will take with it lots of the airborne pollutants from inside the house.
Allowing outdoor air to come in -- when it's crisp and fresh and not heavily laden with smog or pollen -- will refresh the quality of interior air more effectively than any air cleaning system. Instead of cleaning and recycling used interior air, outdoor breezes replace it with a new supply.
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