HEPA Filters
HEPA (High Efficiency Particulate Air) filters are the most effective filters available for the filtration and removal of microscopic particles from the air. According to the Institute of Environmental Sciences and Technology (IEST), a certified HEPA filter must capture a minimum of 99.97% of contaminants @ 0.3 microns in size (about 300 times smaller than the diameter of a human hair). This means that for every 10,000 particles that pass through the filter, only three can be permitted to escape.
HEPA filters have been around for almost 70 years. They were developed in the 1940’s by the US Atomic Energy Commission to prevent the spread of airborne radioactive particles as part of the Manhattan Project. After World War II, HEPA filter technology was declassified and made available for commercial and residential use.
Over the years, HEPA filters have become the industry standard in applications where exceptional air quality is required, including hospital operating and isolation rooms, the aerospace and pharmaceutical industries, and in nuclear and computer chip manufacturing plants around the world.
Today, this same technology is put to work in high-quality room air purifiers to help remove allergens (e.g., dust, pollen, mould spores, pet dander, fabric fibres), airborne pollutants (e.g., tobacco smoke) and micro-organisms that can lead to infection and disease (e.g., some types of bacteria) from the air.
HEPA filters are typically constructed from paper-like glass fibre or polymer sheets. Both allow airflow through the material, but not much else. HEPA filters are pleated many times in a “V” pattern to maximize the surface area within a small volume to enhance their effectiveness in removing particles. Some high-quality air purifiers have as much as 60 square feet of filter material folded inside their HEPA section.
In addition to the amount of filter material, the composition and construction of the filter media can also influence filter performance. Beware of filters marketed as “HEPA-type,” “HEPA-like” or “99% HEPA,” as these do not meet the industry standard and are less effective at removing particles.
HEPA air purifiers are advocated by the American Lung Association as the technology of choice because they do not produce any ozone. Based on an independent laboratory test, the International Association of Air Cleaner Manufacturers (IAACM) reported that 9 out of 10 air purifiers tested produce peak ozone concentrations far above the legal limit, including both ozone generator units and electronic air cleaners. Only the HEPA unit was found to produce no ozone at all. Read article
HEPA filters are recommended by many doctors, and by us here at Modern Alchemy Air Purifiers, to help reduce the symptoms of allergies and asthma. More generally, they can help to improve the overall quality of the air you breathe, and according to a recent study published in the American Journal of Respiratory and Critical Care Medicine, perhaps even reduce your risk of heart disease and improve your cardiovascular health. Read news article
