Carbon monoxide poisoning is the most common form of fatal air poisoning. Colourless, odourless and tasteless, carbon monoxide is so deadly as it is adept at binding with haemoglobin in the blood. On doing this it produces carboxyhaemoglobin, which unlike haemoglobin is completely ineffective in carrying oxygen to bodily tissues.
While carbon monoxide is itself difﬁcult to detect, carbon monoxide poisoning in humans can be seen through the colouration of the skin and lips. This is because carboxyhaemoglobin has a characteristic cherry-red colour and, in large concentrations, causes pigmentation in the skin. Other indications of carbon monoxide poisoning include headaches, dizziness and a weak pulse. One of the biggest contributors of carbon monoxide to the environment is exhaust fumes from combustion engines.