Air Filters - Carbon And Hepa Filters

Written by Norene Anderson
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Air filters are used for purifying the air inside a home or building. The type of filter for optimal contaminant capture will depend on the amount of space to be cleaned and the offending particulates. Circulating fresh outside air is the method of choice; however, many homes and businesses are not located in an environment offering unpolluted air. Industrial pollution, exhaust fumes, pollen, or other particulates are resident in the air most of us inhale.

With all the pollutants in the outdoor air, the indoor air is even worse. This is due in part to the fact that the indoor air is circulated repeatedly with no refreshing. If it is possible, open a window or use an exhaust fan to remove the stale air from inside the home every few days. This will help rid the air of stale odors and some contaminants. It will not cleanse the air of bacteria, mold, and mildew. Special filters are required to capture and destroy some infiltrates.

Air Filters Provide Relief

In spite of the effort to clean the inside air by refreshing with the outside air, many people have serious allergies to household air. Allergy symptoms are a problem for millions of people. An allergen is something the immune system determines is a foreign substance and should not be in the body. The body's response is an allergic reaction to the pollutant.

Many types of allergens affect people in different degrees. Allergic reactions to chemicals, medications, and foods are easy to see and identify. Reactions to inhalants are more difficult to define. Pollen, dust, smoke, and perfume can trigger a major response from someone with sensitivity to the particulate. Sometimes it takes a trip to the allergist for allergy screening to find everything that is active in causing an allergic response.

One of the first lines of defense for indoor allergies is to purify the air. This can be done by either a whole house filtering system or an individual room unit. The whole house system utilizes the central heating and air conditioning unit of the home. All units have at least a basic filter to prevent massive amounts of dust and particles collecting on the operating system. The basic filter is often not sufficient to eliminate all of the particulates in the air.

Choose the Right Filter

A unit for single room use is effective only for the defined area. A unit rated for 180 square feet will not do an efficient job in a room of 500 square feet. It is common for individuals with severe allergies or asthma to require a room unit in addition to the whole house filter. The allergens vary from person to person, but most people with any type of allergy will have sensitivity to dust and dust mites. These tiny microscopic pests can live from two to four months and leave feces 20 or more times a day.

Air filters vary in density, design, and material. It is important to note the level of capture guaranteed by the manufacturer of the filter. Airborne particles are measured in microns. One micron is equal to one twenty-five thousandth of an inch. A good size comparison is the human hair. One hair is about 250 microns and the tiniest airborne particle is .001 micron. To capture the smallest possible particulates, including dust mites, a filter rated to capture 0.3 microns and larger is needed.

Even with the tiny particle capture, it is necessary to use a charcoal or activated carbon filter to capture some of the gasses such as cigarette smoke or radon. HEPA (high efficiency particulate arresting) filters can capture as much as 99 percent of particulates as small as 0.3 microns. Careful evaluation of the pollutants and allergens must be considered to get the type of air filter that will provide the best results. Clean air is essential for good health.


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