What the Heck Are HEPA Filters - and Why Should You Care?

Without HEPA Filters, There Wouldn't Be Any Clean Rooms

RIVERDALE, NJ / ACCESSWIRE / July 16, 2017 / ''HEPA filters have existed since the early 1950s and are the most effective filters you can buy. They are an important component in the effectiveness of any air filtration system that claims to provide comprehensive elimination of harmful pollutants,'' stated Kevin Wood, Camfil USA Vice President Sales & Marketing. ''In basic terms, these filters are rated to trap a higher percentage of very small particles than most common filters on the market, which means better indoor air quality, and better overall health, especially for people suffering from chronic allergies and respiratory problems.''


An air filter's main function is to remove airborne pollutants from the air that circulates through our offices and homes to protect the buildings occupants.1 A HEPA filter is so effective that it is the main line of contamination defense in hospital operating suites, protecting doctors, nurses, staff and of course the patient on the table. They are also used in commercial applications that have a defined extreme cleanliness level (commonly called clean rooms) where microprocessors and pharmaceuticals are manufactured. Without HEPA filters, there wouldn't be any clean rooms; no cell phones, no televisions, and none of the pharmaceuticals we produce to make life more comfortable.

How HEPA Filters Are Different

HEPA is an acronym for high-efficiency particulate air filter. Its original name was high-efficiency particulate arrestor, titled so by the US government when they were developing the filter during the manufacture of the original atomic bomb (the Manhattan Project).2

To be a true HEPA filter, the delivered product must have been individually tested as to its efficiency and airflow and serialized on a label on the filter by the manufacturer. There are different classes of HEPA filters with increasing levels of efficiency, but the minimum level of efficiency must be at least 99.97% efficient on particles 0.3-micron in size. This particle size is 0.000012 of an inch, which is about 300 times smaller than the diameter of a human hair. To a HEPA filter, catching a one-micron size particle (1/1,000,000 of a meter) is the equivalent of stopping a cotton ball with a door screen.

It is important to note that 0.3-micron was selected because it was believed to be the most penetrating particle size of a filter and, if the filter has a high efficiency at 0.3-micron, its efficiency will be greater in other ranges. In a typical atmospheric air sample, there are hundreds of thousands of these particles in a single cubic foot of air.