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

Explanation

The colourless, odourless carbon monoxide gas is severely harmful for human beings and animals. It has a greater affinity towards haemoglobin than that of oxygen. So, it readily displaces oxygen from oxyhaemoglobin `(HbO_(2))` to form the more stable compound carboxyhaemoglobin (HbCO) to give a stable compound, carboxyhaemoglobin.
`HbO_(2)+COiffHbCO+O_(2)` In blood, when the concentration of carboxyhaemoglobin reaches 3-4%, the oxygen carrying capacity of the blood is greatly reduced. In otherwords, the body becomes oxygen- starved. This results into headache, nervousness, cardiovascular disorder, weak eye-sight etc., On the otherhand, `CO_(2)` does not combine with haemoglobin and hence is less harmful as pollutant. `CO_(2)` is mainly responsible for greenhouse effect and global warming.