What level of CO2 is toxic to humans?

This could occur when exposed to levels above 5,000 ppm for many hours. At even higher levels of CO2 can cause asphyxiation as it replaces oxygen in the blood-exposure to concentrations around 40,000 ppm is immediately dangerous to life and health.

How much c02 in the air is dangerous?

The American Conference of Governmental Industrial Hygienists (ACGIH) recommends an 8- hour TWA Threshold Limit Value (TLV) of 5,000 ppm and a Ceiling exposure limit (not to be exceeded) of 30,000 ppm for a 10-minute period. A value of 40,000 is considered immediately dangerous to life and health (IDLH value).

How much CO2 is too much for humans?

350 to 1000 ppm is a good quality concentration in an enclosed room. This is what the Earth is, a confined space. 1000 to 2000 ppm, the air quality is low. From 2000 to 5000 ppm, CO2 concentration starts to cause problems (headaches, insomnia, nausea).