A brief History of HEPA Filters

HEPA filters: Born from a necessity

Many of the technologies we are familiar and comfortable with have their roots in war. That is a sad thing to state, but it is a reality: war often brings out the worst of humanity, but also the best, and it is often that human creativity is then employed to solve complicated problems. All we have to do is look at the computers we use in our daily lives: from the bulky PCs that sit in our desks to the smartphones we carry in our pockets, along with the internet that connects them all, they’re the product of wartime needs.

HEPA filters are not different. They can trace their origins back to the early 1940’s, as a side product of the Manhattan Project, the secret program that developed the world’s first atomic weapons. Working with radioactive materials is dangerous, both for the people involved and the ones around them, since waste material is generated, usually resulting in fine radioactive particles of dust and debris that pollute air indoors.

Scientists and engineers at the US Army’s Chemical Corps and the National Defense Research Committee were tasked to design a filter strong enough to remove toxic and radioactive dust and particles that resulted from the development of the bombs. It was a complicated task, and the first of its kind since nobody had the experience of working with radioactive dust particles before the 1940s. Atom bombs were a novelty at the time, and scientists only had vague ideas about how to deal with the cleanup process. They had to look at some of the existing technology to see what could be useful for the task.

In their research, scientists took apart the masks issued to American soldiers to be used during gas attacks. They found that their filters were made of a special mix of asbestos and cellulose fibers, capable of filtering out most of the toxins released during chemical warfare, enough to keep the soldiers safe and in good combat conditions. They realized that modifications to this design would be perfect to construct a filtering system effective enough to protect the Manhattan Project’s technicians from radioactive dust.

Working around a new design of HEPA filters

The idea was set, but they still needed to develop it, and time was running out. Many brilliant men and women were employed by both fronts during the war, so there was ample talent to ask for advice. One of the people consulted by the US Army’s Chemical Corps was Irving Langmuir, a chemist and physicist who had been awarded the Nobel Prize in chemistry, back in 1932. He had already played an important role in the war effort by improving sonar technology for the detection of submarines, so he was seen as a good consultant for the development of the new filters.

Langmuir, who had experience with atomic theory, was confident that radioactive fallout could be trapped by the new filter, but there was a caveat. The new technology had to be developed around particle sizes of 0.3 microns, which is so small a special microscope is needed to detect them. For perspective, the smallest thing a healthy human eye can see is within the range of 0.1 millimeters, or 0.0039 inches. Langmuir’s election of such size was not random. According to his best estimations, a particle 0.3 microns in size was small enough to be the most penetrating, so the weight of his word was taken at heart by the scientists at the US Army’s Chemical Corps.

With Langmuir’s expertise on board, the new filters were soon developed and employed. Their sizes, however, were big and bulky compared to today’s HEPA. In fact, they were not even known as High Efficiency Particulate Air filters at the time; that’s a name that was given to them years later, when the technology was declassified and made available to the public. Originally, these filters were known as Absolute Filters, due to their effectiveness in the harsh environments where they were employed.

What happened after the war?

Once the conflict was over, the technology was made available to the public. It was soon incorporated in the medical and pharmaceutical industries, and it wasn’t long before residential and commercial spaces adopted it to keep their indoors air pollution-free. Since none of these spaces have to deal with radioactive materials, the technology was further developed to deal with other kind of milder contaminants, such as mold, pollen, PM 2.5 particles, Nitrogen Dioxide (NO2), etc.

Of course, contemporary HEPA filters have seen improvements that the original war designs couldn’t conceive at the time. They usually employ processes that complement the filtering itself. For example, UV-GI lights that degrades bacteria and viruses, Ionisers that generate gas ions that force particles to stick to a plate, and Activated Carbon, which converts chemical molecules from a gaseous to a solid state, which helps control odor.

Today, HEPA filters can be found right at home at some of the most demanding industries’ headquarters. All due the high standards they stand for. To be HEPA, they require to filter 99.97% of all toxic particles, pathogens, and viruses around, a highly valuable skill these days, after the experience we all had to go through during the Covid-19 pandemic.

AIR8 HEPA filters just for you

At AIR8 we believe in the importance of living and working in a Safe Air Space. All our products use medical-grade HEPA-13 technology, and they also incorporate the pre-filtering and filtering processes that have previously been mentioned a few lines above. This makes them the perfect product to keep the air in your office fresh and sanitary, and your employees healthy and productive.

Not only do our filters protect you against indoor concentrations Nitrogen Dioxide (NO2) and PM 2.5 particles, but they are also effective at eliminating aerosols, bacteria, pollen, fine dust, and viruses, such as Covid-19. Our AIR8 filters have the best CADR (Clean Air Delivery Rate) in the market, they are silent, their energy consumption is low, and they cover areas of up to 1399 ft2. Not only that, but they also come in various sizes and capacities for your needs, can be adapted to any office space and can be moved around from one room to the next. You can even try our one-month demo kit for 50% charge.

The quality of our products is backed up by the CE seal, which serves as a testimony of our commitment to the best environmental and health practices, as valued by the European Commission. We also value the long history of our technology. It has proven itself through the years in some of the most extreme and polluted environments, and is now here to keep your office and workspaces fresh and healthy.