HEPA filters were originally developed in the 1940s and used in the Manhattan Project to prevent the spread of airborne radioactive contaminants. After the 1950s, HEPA filters were later commercialized and the term became trademarked and known as a generic term to describe any high efficient filter. Over the years, because of demands for improved air quality in various industries such as aerospace, pharmaceutical processing, and healthcare, HEPA filters became commonly used in these industries to help eliminate airborne particulates such as dust, dander, mold, and asbestos.
In order to be considered a True HEPA filter, a filter must be capable of removing at least 99.97% of particulates as small as 0.3 microns. Particles of this size are the most difficult to filter, and they are thus considered the most penetrating particle size, or MPPS. HEPA filters consist of a mat of randomly arranged fibers that target and trap small particles by one of the following three mechanisms:
1. Interception - When particulates follow a line of flow in the airstream within one radius of a fiber and sticks to it.
2. Impaction - When large particles cannot avoid the HEPA fibers and are forced to imbed in one, which also increases with diminishing fiber separation and higher air flow.
3. Diffusion - When an enhancing mechanism results from the collision with gas molecules by small particles, which are impeded and delayed through the HEPA fiber.
Therefore, because of the superior filtration abilities of HEPA filters, they are extremely effective at removing particulates from the air and from surfaces such as carpets and upholstery, and their use can help make the air we breathe significantly healthier. Because our indoor environment contains allergens, chemicals, gas, dust mites, mold, and other harmful microorganisms, the respiratory tract struggles and suffers daily from these harmful pollutants. Poor indoor air quality can also cause symptoms such as itchy eyes, headaches, digestive problems, fatigue, congestion, and many more chronic and acute diseases. In fact, studies have shown that more than every one in three adult, child, or infant suffers from allergies, asthma, or respiratory diseases, and currently, asthma is one of the leading causes of upper respiratory illnesses in children.
Today, most HEPA filters can be found in air purification systems and even vacuum cleaners. HEPA vacuum cleaners use HEPA filters as part of the filtration process, and they are extremely beneficial for asthma and allergy sufferers, as the HEPA media is able to trap the fine particles that can trigger asthma and allergy symptoms. For a HEPA filter in a vacuum cleaner to be effective at particle abatement, the vacuum cleaner should be designed so that all of the air that is drawn into the machine is passed through the filter, with none of the air leaking past. In addition, because of the density of a HEPA filter, a HEPA vacuum cleaner will need a more powerful motor to provide sufficient cleaning power.
There are essentially two basic styles of HEPA vacuums: canister and upright. HEPA canister vacuums usually have smaller, stronger cases that can roll along and follow behind you as you vacuum carpet, furniture, or the floor. A long hose attached to a HEPA canister vacuum cleaner will help you clean hard to reach places. HEPA canister vacuums also often feature detachable rug beaters that are more powerful when compared to those found on upright HEPA vacuums. When the electric motor powered rug beater on a canister vacuum cleaner stops working, the unit can still be used to clean other surfaces. Overall, for homes with mostly bare floors and sparse rugged areas, canister vacuums can help you move seamlessly from one area to the next without scratching your floors.
On the other hand, upright HEPA vacuums consist of a single unit that may or may not come with an attachment hose to help clean hard to reach areas with specialized vacuum tools. Upright HEPA vacuums may leak dusty air back into your home, and since the rug beater bar is permanently attached to the vacuum's case, once this important component breaks, the entire vacuum will have to be replaced. However, if your home is mostly carpeted, a traditional upright HEPA vacuum may be a better choice, as its beater bar can better churn up dirt and dust embedded below the surface of your carpeting.
In terms of design differences, that are different styles of HEPA canister vacuums available, with the most common being those units with plastic cases utilizing a disposable dust collector bag made of plastic used to catch the dust from your carpet and into the vacuum cleaner. Keep in mind that with these types of models, dusty air may still leak through gaps in the plastic gases and even pass through the exhaust and back into your home environment.