HEPA Filters: The Experts’ Choice

HEPA filters are the gold standard for air filtration, used by professionals and individuals alike. HEPA technology – both revolutionary and time-tested – is the most effective way to remove airborne particulates that can irritate the respiratory system. This improves indoor air quality and may help protect one’s long-term health.

History of HEPA Filters

High efficiency particulate air (HEPA) filters were first developed during the 1940s and used in the Manhattan Project; the US government’s research already showed that exposure to radiation was lethal, so they needed a way to protect the scientists from the spread of airborne radioactive particles. HEPA filters were the answer. After WWII, the technology was declassified and became available for commercial use.

HEPA Construction

Filter mats are made of borosilicate fibers that are randomly arranged to form a sheet. The mats are then arranged in pleats in order to maximize the amount of surface area. Because of these pleats, fairly compact HEPA filters can remove large amounts of particles. When air flows through the filter mats, particles are trapped by the borosilicate fibers and removed from the airflow. The particles remain trapped in the filter as the clean air continues out of the filter. To be rated a HEPA filter, it must remove 99.97% of airborne particles .3 microns and larger.

Three Means of Particle Removal

HEPA filters trap particles in three ways: inertial impaction, interception, and diffusion. Larger particles – greater than 1 micron – are trapped via inertial impaction. Their relatively large mass means that inertia keeps them moving in a straight line toward fibers, even when the airflow diverts around the fibers. The large particles then impact the fiber, essentially sticking to them. Medium-sized particles are not big enough to be subject to a meaningful amount of inertia, but if they pass close enough to a fiber – within one fiber radius – they get intercepted by that fiber and stick to it. During diffusion, small particles – of less than .1 micron – randomly travel through the air, colliding with gas molecules and effectively bouncing around. Collisions with other molecules knock them into fibers if they pass closely enough. In this way, particles of various sizes are trapped, removing them from the air that leaves the filter.

Use of HEPA Filters

HEPA filters are routinely used in many professional settings – in hospitals, during the manufacture of pharmaceuticals, of microchips, and in many other places. They are especially useful in medical facilities since they have been proven effective at helping stem the spread of viruses and bacteria. The Centers for Disease Control and Prevention even advised that healthcare professionals should use portable HEPA air purifiers to help combat the 2009 swine flu epidemic. But HEPA filters are not just for these professional settings. Portable HEPA air purifiers have become an effective way to reduce indoor pollutants in the home, as well.

Portable HEPA Air Purifiers

The Environmental Protection Agency has warned of the dangers of poor indoor air quality. HEPA air purifiers are one means of reducing indoor pollution in the home. These individual units contain HEPA filters that effectively remove pollen, dust, mold spores, dander, viruses and bacteria. Often air purifiers combine HEPA filters with other filters – like one made of activated carbon – to remove an even wider range of pollutants from the air. Activated carbon filters remove odors, volatile organic compounds, smoke, smog, and fumes from household cleaners, among others. All of this helps to reduce the concentration of pollutants found in indoor air. These airborne pollutants can irritate the respiratory system, so their removal may help alleviate allergy symptoms, asthma symptoms, and the symptoms of other respiratory conditions. Indeed, studies have shown that the use of HEPA filters and other allergen-reducing measures significantly reduces asthma symptoms in children.

While HEPA filters are not a cure-all, breathing healthy, clean air helps to promote better overall health. For those concerned about indoor air quality, a HEPA air purifier can be a helpful tool in their arsenal.

Printable Version

Air Purifiers
Austin Air
IQAir
Amaircare
Replacement Filters
Shower Filters
Rainshower

View Cart Checkout