Carbon monoxide gas is more dangerous than carbon dioxide gas. Why?

Explanation

Carbon dioxide `(CO_(2))` and carbon monoxide (CO) gases are emitted during the combustion of varioue fuels. Carbon monoxide is poisonous because it is capable of forming a complex with haemoglobin (carboxyhaemoglobin), which is more stable than the oxygen-haemoglobin complex. The concentration range of 3-4% of carboxyhaemoglobin decrease the oxygen-carrying capacity of blood. This result in headaches, weak eyesight, nervousness, and cardiovascular disorders. A more increased concentration may even lead to death.
Carbon dioxide is not poisonous. It proves harmful only at very high concentrations.