PCO vs HEPA Air Purifiers: Which are the Best?

PCO vs HEPA Air Purifiers: Which are the Best at Home?

PCO vs HEPA Air Purifiers: Which are the Best?

Air purification is becoming an essential step in taking care of our health. PCO air purifier are – by far – the most effective technology to fight indoor air pollution.

Recently the issue of indoor air purification has been growing more and more, because people's time at home has increased, as their attention to pollutants that are harmful to our health. 

Every day we take about 20,000 breaths, so we can say that if the quality of our air were not good, our health and our body would suffer. So it is our duty to take care of our health, using purifiers that allow us to obtain safe, clean, and fresh air to face our days at home with serenity.

However, there are many doubts about which are the best solutions among the various purifiers because as the market is constantly expanding, the choices for consumers have also increased. Choices that can cause uncertainty and doubts in understanding the various differences that distinguish the various purifiers for indoor environments. Let's now analyze in detail the main types of filters that can be purchased on the market and why photocatalysis is an interesting and valid option for our well-being.

What are PCO and HEPA air purifiers?

HEPA (High Efficiency Particulate Air-filter) has been the most common air purification technology in the last 80 or so years. This technology proved extremely valuable, and it was first applied in chemical factories and nuclear plants during World War II.

More recently, however, the PCO air purification technology (Photocatalytic Oxidation) began to show results which, in the eyes of the international scientific community, represent a huge improvement from HEPA technology, and the future of air purification.

KOru PCo air purifier

In fact, many air purifier manufacturers are now changing their products in favor of photocatalysis as a method to remove pollutants from the air, and some of the major air purifiers manufacturers that have traditionally been using HEPA filters are starting to either adding to it, or swapping it altogether for PCO filters.

Advantages of PCO air purification

PCO is an innovative air purification method that instead of simply “capturing” pollutants on their filter unit (as HEPA filters do), eliminates them thanks to a unique chemical reaction, transforming them into harmless substances such as carbon dioxide (CO2), water, and salts. This chemical-electric process of “deconstruction” of the air pollutants is what makes PCO filters far more incisive than HEPA when it comes to air purification.

This is the main reason that brought our engineers at Botany Labs to focus on the PCO technology, while many other companies still focus on HEPA.

Another fundamental element of PCO filters is that the filter does not need to be replaced or changed over time because, contrary to HEPA filters, the deconstructed pollutants in PCO systems are too tiny and light to actually sit on the filter, clogging it over time. Actually, even the catalyst (the substance air filters in PCO systems are usually “coated” with) is not “consumed” in any way by the chemical reaction, thus making the coating last virtually forever. This fact alone, unquestionably entails major economic savings as well as and full respect for sustainability.

On top of this, by analyzing the technical data of photocatalysis, we can also find that PCO filters have the ability to eliminate particles as small as 0.001 microns, including those microparticles that for they small size have the ability of penetrating in our lungs, where they are absorbed and can cause huge health problems. All this while HEPA filters are capable of filtering only particles up to 0.3 microns.

Finally, several studies have shown that in addition to VOCs, toxic gases, and chemicals, PCO air purifying units can also turn harmless many dangerous gases such as carbon monoxide and nitrous oxide, all unsafe pollutants that can often escape standard devices using only HEPA technology.

indoor air pollution cooking gas

The downfall of HEPA air filters

The HEPA (High Efficiency Particulate Air-filter) filter has been the best known and most used type of air filter on the market for almost 80 years, as it guarantees excellent performance in terms of air purification and flow rate.

HEPA technology purifies the air thanks to the mechanical blocking of pollutants within the narrow mesh of its filter(s); in this way the air that makes it beyond the filter is “purified” since the pollutants have been "captured" by the thick layers of the filter, which certainly makes it an efficient and functional technology for different purposes and needs.

Nevertheless, there are some major criticalities and problems related to HEPA filter’s functioning that cannot be ignored, as they pose either a huge threat to our health, or a big issue when it comes to sustainability.

Firstly, HEPA air purification units cannot filter any pollutant smaller than 0.3 microns. While this may seem like an already “good enough”, the vast majority of the harmful compounds that make-up what we call air-pollution are way smaller than this, measuring anything in between 0.001 and 0.5 microns.

On top of that, HEPA filters need frequent replacements in order to maintain their effectiveness, making them quite more expensive – over time – and far less sustainable than photocatalytic filters. HEPA filters cannot be recycled, and end up in landfills where they are incinerated, adding to the overall problem they deem to resolve in the first place.

Why chose a PCO air purifier

While there are several air purification technologies out there, many of which promising great results, years of study and laboratory testing gave us the clear answer we were looking for: photocatalysis is – currently – the most effective, efficient, sustainable, and economically smart air purification technology available to consumers.

What do PCO air purifiers filter?

Viruses, Bacteria and Microbes

One of the photocatalytic process’s key feature is its ability to sterilize microorganisms, preventing them from growing or infecting further. Airborne viruses, microbes, bacteria, fungal spores, and fungal fragments are trapped on the catalyst (the filter) where they are subjected to the oxidation by the photocatalytic process.


In addition to microbes, small particles called allergens can also be harmful by causing dangerous allergic reactions that are at best uncomfortable, and at worst can impact productivity and health. The oxidative effect of photocatalysis can break down allergens very effectively, so they don’t stimulate any allergic reaction to begin with.


Volatile organic compounds are dangerous to our health, particularly if they come from industrial by-products like paint, furniture, or building materials. VOCs are very vulnerable to oxidation by photocatalysis, though. 


Many PCO devices use UV-C light to enable their catalytic reaction. UV-C light is well-known for its ability to convert oxygen to ozone. In fact, the ozone layer in the upper atmosphere is formed from oxygen being exposed to UV-C light emanating from the sun. Modern air purifiers for home and offices use a different band of UV light called UV-A, which is the same light used in tanning bed bulbs and in the “black light” bulbs that make posters glow fluorescently.

HEPA filter dirty

Are PCO air purifiers safe?

When considering a photocatalytic system, it is very important to be sure it is efficient enough to not produce any byproducts. There are several factors that influence the efficiency of a PCO device.

What are the most important factors to consider when evaluating PCO filters?

Ozone free

The California Air Resources Board (CARB) does not allow air purifiers to be sold in California that produce unsafe levels of ozone, so make sure the PCO system is listed as CARB compliant. All KORU PCO air purifier has been certified and independently tested to not produce any ozone – in fact, KORU’s PCO technology could even be able to reduce the levels of ozone.

Long dwell time

Air pollutants have to spend enough time in contact with the catalyst in order for it to be exposed to enough oxidation, which is normally referred to as the pollutant’s dwell time.

Research the alternatives

This is one of the most important aspects to pay attention to when selecting a photocatalytic air purifier. Look for tests done by laboratory companies external to the manufacturer and see how well it can destroy pollutants like VOCs and microbes. If there is no research available, then it’s possible the unit is inefficient at best or totally ineffective at worst.

dangerous air pollution

Indoor air pollutants are harmful materials that pose environmental health risks. Elimination of these pollutant sources will help to improve air quality for inhalation.

Ventilating your home is usually the best option, but most ventilation methods are limited by weather conditions and recurrent air contaminants.

The use of air cleaning appliances happens to be a real, effective solution.

A conclusive note

PCO technology is a fundamental scientific innovation in the air purification industry. While some PCO devices fall short of taking full advantage of the photocatalytic process, by employing low-quality electronical components and filters, they still represent a huge technological leap forward when compared to HEPA.

Luckily, the latest advancements in air purification technology allowed us to develop KORU Air focusing on maintaining an extremely high air purification effectiveness, while limiting our impact on the planet and on customer’s pockets with a permanent and washable filter perfect to capture even up to 99% of virus and bacteria.

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