Residential Purposes of hepa filter
Every house with plants, pets or people is automatically polluted. According to the EPA, the air in most homes is at least two to four times more polluted than outside air.
Most of us spend up to 90 percent of our time indoors breathing polluted air and only 10 percent of the time breathing healthy, oxygen-rich outdoor air. The result is that many of us suffer from asthma, allergies and hypersensitivity.
According to the EPA publication The Inside Story: A Guide to Indoor Air Quality, the less fortunate can come down with respiratory diseases, heart disease and cancer after prolonged or repeated periods of exposure to some pollutants.
The American Lung Association reports that 24.7 million Americans have been diagnosed with asthma some time in their lives and that in 1999 alone, close to 2 million emergency room visits were attributed to asthma.
The two primary methods of preventing indoor air pollution are source control and cleaning the air.
Source control: If there are no pollutants, there is no pollution. Unfortunately we live in a very dirty world. On a practical level, source control is as simple as using pump bottles instead of aerosol spray cans, not letting anyone smoke inside the house and exhausting bathroom fans through the roof, not into the attic. It also means waterproofing and ventilating the basement so that it never gets damp and making sure the roof doesn't leak.
Cleaning the air: At the most basic level, the furnace filter takes hunks and chunks out of the air. The American Lung Association recommends upgrading furnace filters to at least the quality of the 3M Filtrete or other electrostatic filter. You also can upgrade to thick media filters, such as the Air Bear, or electronic air cleaners, such as the Trion Max 5 or the Honeywell Electronic air cleaner.
HEPA filtered air cleaners, air purifiers and vacuum cleaners are highly recommended for all allergy and asthma sufferers.
The American Lung Association recommends that proven source control strategies be employed in homes as a primary means of reducing exposure to pollutants, that is, getting at the real source of what causes pollutants and reducing it or removing it. However, physical studies which do not measure health effects do show that certain air cleaners are effective in removing certain indoor air pollutants. Thus, as an adjunct to effective source control and adequate ventilation, highly efficient air cleaners can be useful in further reducing levels of certain indoor air pollutants. More research on the health benefits of air cleaners is needed to provide complete evidence that would better address the circumstances of intended use.
Based on the limited available data, it can be concluded that if allergen sources are present in a residence, air cleaning alone has not been proven effective at reducing airborne allergen-containing particles to levels at which no adverse effects are anticipated. Cats, for example, generally shed allergen at a much greater rate than air cleaners can effect removal. Dust mites excrete allergens in fecal particles in sequestered environments (i.e., within the carpet or the bedding). For individuals sensitive to dust mite allergen, the use of impermeable mattress coverings appears to be as effective as the use of a laminar flow air cleaning unit above the bed. Source control should always be the first choice for allergen control in residences.
The reality in most residences is that total elimination of a pollutant source is not always possible or practical. Individuals with severe allergy and asthma symptoms, whose symptoms are not alleviated by other source control and ventilation strategies, may want to try an effective air cleaner in an attempt to aid in further exposure reduction. Although there is no proven health benefit from such a measure, some individuals report that they perceive air cleaners as useful in improving their health status.
Unfortunately, for residential use, HEPA filters can be noisy when used in air filter systems due to the fan and can be expensive due to electricity costs. To reduce noise, the air intake duct and intake fan is often located outside of a building, oftne on the roof of the building. Replacement filters can also be expensive as HEPA filters are not reusable. Despite this HEPA filters are easily the most effective filters available and their use can improve allergic symptoms dramatically.
HEPA filters (recommended by the Dept. of Homeland Security) are more effective than any other type of air filter at capturing dust, pollen, ragweed, dust mites, mold spores and other allergens.