The WHO has recognized air pollution as an invisible health threat responsible for about 7 million premature deaths per year, of which 3,8 million are attributed to indoor air quality. Due to the associated link between air quality and health, the general concern about improving air quality has been significantly increased in the past years. Various air treatment technologies have gained interest, including physicochemical technologies (e.g.: filtration (HEPA), adsorption, UV-photocatalytic oxidation, ozone generator, plasma, ultraviolet disinfection and ionization) and biological technologies (e.g., plant purification methods and microalgae-based methods).

Although their performance is well defined and very efficient in specific areas, there are several limitations to consider. One of the most common problems from these technologies is that they do not cover the simultaneous removal of all pollutant types, including microorganisms, gaseous contaminants and particles. Most of these technologies do not remove any of the harmful gaseous indoor contaminants (VOCs, formaldehyde, NOx, SO₂…) and sometimes, they emit more dangerous pollutants than those they can remove. For example, the release of toxic byproducts (such as ozone) by all kinds of UV or plasma purifiers should be carefully controlled and efficiently removed. Other technologies focus on the removal of microorganisms and do not focus on eliminating gas pollutants at all. To ensure a fully effective indoor air purification, the optimal solution appears to be the combination of different technologies. Some purifiers contain activated carbon foams as a mean of removal of volatile organic compounds generated indoor or the ozone generated from the purifiers. However, the adsorption capacity and gas type selectivity of these activated carbon foams is very limited, not reaching its purpose.

For the appropriate removal of most indoor gaseous pollutants, a blend of at least two different types of absorbent media is needed. A high surface area active carbon should be used for efficient physisorption of ozone and high molecular weight volatile organic compounds (VOCs), and a different type of adsorbent, including some chemically active ingredient, such as potassium permanganate, favoring the chemisorption of formaldehyde, ketones, aldehydes, alcohols NOx, SO₂, among others, is required. Other types of adsorbents can also contribute to the removal of amines and ammonia, which when generated indoor can cause health effects associated with strong odors.

In this work, we critically review and address the limitations of the most commonly used air filtration technologies through the implementation of a novel, holistic combination of air purification systems, air conditioning systems, and physical and chemical gas adsorption systems. Laboratory test have been performed with adsorbent media with promising results in the adsorption of NOx, SO₂, and formaldehyde. This integrated approach leverages the strengths of each technology, providing a comprehensive solution that ensures both comfort and healthy indoor air.