When it comes to most air-purifying systems, one of if not the most common method of cleaning is the one that uses what’s known as HEPA filters. HEPA, or High-Efficiency Particulate Air, is the centerpiece of most air purifying systems promising to improve the air-quality in your home or workplace. And as we have written about before, air quality affects many things including sleep and health.
However, HEPA filters are not perfect, in fact for most personal and residential use, they are far from it. There are risks to using HEPA filters that not many people will admit or talk about, but have to be brought to light in order to understand what a HEPA filter-based air-purifying system really can do.
The History of HEPA
Let’s take a quick look at the origins of the HEPA filter. According to Britannica.com, HEPA filters were first created in the 1940s to help contain the spread of airborne radioactive contaminants during the Manhattan Project. Within 10 years, HEPA filters were introduced to the commercial market as a means to protect from viruses, bacteria, pollen, fungi, human hair, animal dander, dust, and much more.
HEPA filters grew in popularity from there as technology advanced, and have been used in commercial aircraft, hospitals, and other areas that require a lot of sterilization. Eventually, HEPA filter systems used in critical medical facilities have been used in conjunction with ultraviolet light sterilization systems, which aim to kill the bacteria and viruses caught in the filters.
The US Department of Energy created the HEPA Standard and the European Committee for Standardization has the European HEPA Standard counterpart.
How it works
To put it simply, a HEPA filter works very similarly to any kind of filtration system. Think of it like a sieve, but instead of catching cooked spaghetti noodles while allowing water to go through, the tangled mesh of fibers that comprise a HEPA filter catch particles instead. It is very reliant on this mechanical filtration method that is dependent on the size of the gaps and the size of the particles. So if the particles are large enough, say like pet dander, dust mites, pollen, and other pollutants, it works.
However, there are certain pollutants that do not stop being a threat when caught in the filter, and this is where the risks escalate.
The risks
Because it is dependent on the size of the gaps and the size of the contaminants, HEPA filter effectiveness is not perfect. There are a number of contaminants that can get through, and in most cases it is these contaminants that can really cause harm, especially in today’s period of the COVID-19 pandemic.
Viruses are the highest risk factor in using HEPA filters. The US Federal Trade Commission last year sent out warnings to sellers of scam Coronavirus treatments, including two companies that claim their HEPA air purifier products can catch the SARS-CoV-2 virus that causes COVID-19. HEPA filters alone simply cannot stop the coronavirus, or any virus for that matter, as the viruses are too small.
Volatile Organic Compounds or VOCs are also risk factors. These airborne chemicals are also far too small for HEPA filters to trap. VOCs require a different kind of filtration and sterilization system, one that is not just reliant on HEPA filters.
Both bacteria and mold can be caught by HEPA filters. However, once caught the bacteria and mold can still cause damage because in most cases, the bacteria and mold continue to be active while in the filter. The bacteria can still release endotoxins into the airstream up until they finally die, but the mold can actually grow and multiply on the filter membrane, especially because the particles that get trapped can feed the mold spores.
The danger is then present within the air purifying device, but the factor increases once it is time to replace the HEPA filter. Because the HEPA filter will get clogged sooner or later, replacing it is part of owning a HEPA filter-based air-purifying system. It is at this crucial moment that the person replacing the filter will have the highest exposure to the mold and bacteria caught within the filter, and that can cause a lot of problems.
The solution
Does this mean then that HEPA filters are not useful? No, not really, just that their uses are not unlimited and that their effectiveness is not absolute. The solution to this is what was mentioned earlier: to use the HEPA filter in tandem with something else, like a UV sterilization system, to kill the bacteria and the mold that are caught.
However, there are better methods available to deal with the limitations that HEPA filters have, such as more advanced UVC sterilization methods and better and safer filters, among others. Our products utilize both to eliminate the risks posed by HEPA filter use. If you would like to learn more, contact us and we will be more than happy to give you more information and a tech-demo!