The short answer is no: an air purifier does not remove CO2 from the air. This is not a matter of a good or bad device; it is due to how an air purifier fundamentally works. Below we explain why, and what an air purifier can do for you.
How an air purifier works
An air purifier draws in air with a fan and directs it through one or more filters, usually a pre-filter, a HEPA filter, and sometimes an activated carbon filter. These filters capture particles: fine dust, pollen, household dust, bacteria, virus particles, and certain odorous substances. A HEPA13 filter, for example, captures up to 99.97 percent of particles up to 0.3 micrometers, as is also the case with our AirPure Plus PA244.
Why CO2 is not among them
CO2 is not a particle that can be filtered out of the air like dust or pollen. It is a gas molecule that is dissolved in the air itself everywhere, in a concentration that in an ordinary room can easily amount to hundreds to thousands of ppm. To remove CO2 from the air structurally, you need a chemical process that is specifically tailored to CO2 molecules, so-called CO2 scrubbing with, for example, soda lime or amines. That technology is used in submarines, spacecraft, and some industrial applications, not in consumer air purifiers.
An activated carbon filter is no exception
You might think that a carbon filter, which is precisely intended to capture gases and odors, would do something here. In practice, activated carbon is mainly effective against VOCs (volatile organic compounds) and odor molecules, which easily attach themselves to the carbon surface. CO2 is a small, stable molecule that hardly binds to it, and moreover, the amounts of CO2 in a room are far too large to be captured by a filter of limited size.
The difference between air purification and ventilation
This is the core of the confusion: an air purifier purifies the air that is already present in the room; it does not refresh that air with air from outside. Ventilating (opening a window or ventilation grille) is the only thing that actually brings new, low-CO2 air inside and dilutes the accumulated CO2. An air purifier and ventilation therefore solve two different problems, and do not replace each other.
What an air purifier can do for you
If you suffer from fine dust, pollen, household dust, pet hair, cooking smells, or cigarette smoke, then an air purifier with a HEPA filter is indeed useful. In our experience, the AirPure Plus PA244 is a good choice for that: with a CADR of 260 m³/h, it is suitable for up to 55 m², and with three settings and a night mode, you adjust the noise level to the time of day.
In summary: two devices, two problems
Do you have a CO2 problem, usually recognizable by a stuffy feeling in a small, enclosed room, then ventilating is the only solution. Do you suffer from fine dust, allergens, or odors, then an air purifier can really make a difference. Curious which device suits your situation? Look at dynter.eu for the full range.