Source

Carbon monoxide [CO(g)] occurs in exhaust emissions from cars and other vehicles. The fuels that the vehicles used are mostly carbon-containing. Normal combustion of petrol produces only carbon dioxide and water.

Using heptane as an example of a fuel, complete combustion of this is:

With limited supply of oxygen, the exhaust may contain certain amount of carbon monoxide and carbon particles (known as soot). This is called incomplete combustion.

Health Effects

CO(g) is a poisonous gas on account of having an affinity of haemoglobin, the red pigment that carries oxygen in blood, some 250 times greater than oxygen itself. The combination, carboxyhaemoglobin, is not released and prevents oxygen from combining with it. Continued inhalation leads to death as all haemoglobin become attached to CO(g) (the condition known as asphyxia).

In small concentrations, it may cause dizziness and headache. The concentration rarely exceed 4% and it never accumulate due to bacterial and algal action. Cigarette smokers often have their concentration of CO(g) in blood up to 10%.

I would love to hear your comments. Please e-mail to [email protected]