Carbon monoxide is a pollutant with respect to humans because it reacts with haemoglobin. Haemoglobin is a molecule found in red blood cells that is responsible for carrying oxygen throughout the body. When carbon monoxide enters the bloodstream, it binds to haemoglobin much more easily than oxygen does. This means that the haemoglobin becomes saturated with carbon monoxide instead of oxygen, resulting in a decreased amount of oxygen being delivered to the body`s tissues and organs. This can lead to serious health effects, such as oxygen deprivation, which can cause dizziness, confusion, and even death. Therefore, carbon monoxide is considered a pollutant as it interferes with the normal functioning of the human body.