This is what ChatGPT has to say on the subject:-
The difference in acceptable CO2 levels between submarines and office buildings is due to different environmental and operational constraints.
Enclosed Environment: Submarines operate in a highly enclosed environment where air cannot be easily exchanged with the outside. This leads to a natural accumulation of CO2, making higher levels unavoidable.
Air Filtration and Recycling: Submarines are equipped with advanced air filtration and CO2 scrubbing systems to manage air quality. These systems can handle higher CO2 levels effectively, unlike typical office HVAC systems.
Occupational Health Standards: Office buildings adhere to civilian occupational health standards that prioritize comfort and long-term health, aiming to minimize any impact on cognitive functions and overall well-being of the occupants.
Operational Necessity: Submarines often have to remain submerged for extended periods without venting or taking in fresh air. The operational demands and limitations necessitate tolerating higher CO2 levels.
Adaptation and Training: Submarine crews are trained and gradually adapted to higher CO2 levels, something that is not feasible or necessary for office environments.
The higher tolerance for CO2 in submarines is a trade-off between operational needs and environmental constraints, whereas office buildings prioritize occupant comfort and health under normal environmental conditions.