Ionizer vs. Air Purifier - What's the difference?

Room air purifiers, air scrubbers, air purifiers and air ionizers: since the outbreak of the Corona pandemic, many air purification devices have come onto the market to filter indoor air and promise us healthy indoor air. But where is actually the difference between the technologies? And what is really healthy air? A comparison of the technologies for air purification provides an understandable overview.

Air purifier with Hepa filter

Hepa Filter | HEPA Filter | Air Purifier with Hepa Filter

The basis of most air purifiers is the Hepa filter (High Efficiency Particulate Air Filter, pictured left). This filter is a particulate air filter that traps particles suspended in the air. It is usually made of synthetic materials or cellulose and forms close-meshed layers through which the particles are passed by airflow. The meshes are so dense that, depending on the Hepa standard, up to 99.995% of all airborne molecules are captured. If an air purifier has several filter stages, the Hepa filter is often the first filtration technology, as it captures the majority of all airborne molecules.

Luftreiniger mit Hepa Filter | Nahansicht Hepa Filter

The disadvantage: Hepa filters bind particles above a certain size. Tiny nanoparticles, formaldehydes, other gases and odors, and especially tiny viruses often pass through the Hepa filter without major problems.

(Picture right: close-up of a HEPA filter)

Room air purifiers with UV radiation and the problem of ozone generation.

Air purifier with UV radiation | UVC disinfection of indoor air

Another technology included in some room air purifiers is disinfection by means of UV or UVC radiation. This function, when used properly, can render harmless any remaining organic or biological pests such as viruses, germs and bacteria. The ultraviolet light causes damage to the DNA envelope of the microorganisms, thus ensuring that they do not reproduce further and/or die directly.

The problem is that the generation of UV or UVC radiation simultaneously causes the generation of ozone. Here it is particularly important to ensure that the selected air purification device complies with specified limits in the ozone output. The limit values for a daily average in Switzerland are 35 ppb or 70 µg/m3 (micrograms per cubic meter).

Other important filter technologies: Activated carbon filters and thermal sterilization

Many rather inexpensive room air purifiers use a single technology (mostly air purifiers with Hepa filters) for air purification. Somewhat more expensive devices often have a second technology. This is in many cases UV disinfection (as described above), in other cases it is filtration with activated carbon. Activated carbon filters bind formaldehyde, harmful gases and odors in tiny chambers and are therefore well suited for eliminating these pollutants.

Another filtering technique is thermal sterilization. In this process, the air is heated very locally inside the unit so that organic material is destroyed.

Makes a real difference: Ionization

One of the most effective methods for room air treatment or room air cleaning is ionization (often also called ionization). With the help of electric charge, small flashes are generated inside the device at very short intervals, which split ions from particles in the room air. These ions have two effects at once.:

  1. They effectively eliminate nanoparticles, viruses and other micro-pollutants
  2. You can specifically ensure that oxygen uptake is increased with each breath.

Conclusion: difference between air purification and ionization of air

In summary, air purifiers often use a limited range of possible filtration techniques to act only on indoor air. Ionizers, on the other hand, generate ions that can both affect indoor air and have positive health effects on people.

You may now be wondering which features and techniques are particularly important. The answer is: all of them.

Each filtration principle has its own strengths and weaknesses in eliminating airborne molecules. So if you want to play it safe and achieve the greatest possible health benefits, you should choose a device that combines as many filtration techniques as possible and also make sure that the room air is ionized.

Comparison of filter technologies between Dyson air purifier, Xiaomi air purifier, Aircleaner and Biow

The all-rounder - Biow air purifier and ionizer

Biow air purifier and ionizer | best air purifier with ionization | professional air purification | sleep well

One such "all-in-one" air purifier and ionizer is Biow. Biow combines a professional, comprehensive air purification consisting of 5 different filtering techniques with the ionization of indoor air. This premium model is more than just an air purifier. Because thanks to effective ionization, Biow provides not only fresh and healthy indoor air, but also a wide range of health benefits. These include, among other things, a noticeable improvement in the respiratory tract, which promotes, among other things, a deep and restful sleep. Smokers, allergy sufferers and sleep apnea patients can also benefit from improved sleep and alleviation of symptoms.

Schweizer Verein für Luft- und Wasserhygiene (SVLW),,