Just google something like "Acceptable CO2 Levels in Commercial Buildings" or check out UK government website on hazards of CO2. [1]
I personally might be more sensetive than others, but real issues start when PPM going over 2000. Two sleeping people in small room with bad ventilation can easily bring it as high as 2500 in 3-4 hours.
Also if you're cooking on gas in small appartment and have bad ventilation you can easily bring it to 3000-4000 in much shorter period of time.
I personally might be more sensetive than others, but real issues start when PPM going over 2000. Two sleeping people in small room with bad ventilation can easily bring it as high as 2500 in 3-4 hours.
Also if you're cooking on gas in small appartment and have bad ventilation you can easily bring it to 3000-4000 in much shorter period of time.
[1] https://www.hse.gov.uk/carboncapture/carbondioxide.htm