Which of the following air pollutants has a very strong affinity towards the haemoglobin of human blood?

Carbon monoxide binds to haemoglobin with an affinity far greater than that of oxygen.

It forms carboxyhaemoglobin, which blocks the blood from carrying enough oxygen.

Carbon dioxide is carried by blood but does not bind haemoglobin with such strong affinity.

Nitric oxide affects blood vessels but is not the classic haemoglobin-blocking pollutant here.

Nitrogen dioxide chiefly irritates the lungs rather than seizing haemoglobin.

Its affinity for haemoglobin is roughly two hundred times that of oxygen.