MOXIE being placed into a Mars rover
Image: NASA
MOXIE (Mars oxygen in-situ resource utilization experiment) is a box about the size of a lunch box that weighs about 17 kg (37 lbs), requires 300 W worth of power (about he same power consumption as that of 5 laptops) and is capable of producing about 10 g of oxygen per hour on Mars where the atmosphere is 9%% CO2. That is comparable to the output of an average tree on Earth.
Assuming CO2 in the Earth's atmosphere is an issue - could be develop a similar tech for terrestrial use? By the way, given that there are bacteria who do the job and can be bred easily, so the problem, even if it exists, can likely be easily remediated, and there may be many efficient, inexpensive technologies allowing us to do that.
References
Machine Just Turned Martian Atmosphere Into Pure Oxygen Just Like a Little Tree
Andy Corble, ScienceAlert, 2 September 2022
MOXIE
NASA