Do we have evidence that CO2 is causal or is it still just a correlation? In general, poor ventilation + humans = high CO2, so unless there was a controlled experiment done that's a pretty strong confounding factor.
> Results showed increasing the CO2 concentration to just 800 ppm, a level identified as well ventilated, resulted in an increase in viral aerostability. After 40 minutes, when compared to clean air, around 10 times as much virus remained infectious when the air has a CO2 concentration similar to that of a crowded room (3,000 ppm).
> Dr Haddrell said: “This relationship sheds important light on why super spreader events may occur under certain conditions. The high pH of exhaled droplets containing the SARS-CoV-2 virus is likely a major driver of the loss of infectiousness. CO2 behaves as an acid when it interacts with droplets. This causes the pH of the droplets to become less alkaline, resulting in the virus within them being inactivated at a slower rate.
CO2 in terms of illness is merely a proxy for good air movement and exposure to the outside environment. It has its own impact on mental capacities of course.
