A colourless, odourless, inflammable, toxic gas present in large quantities in the waste water from mined gases, especially in exhaust fumes from motor vehicles. This is the pollutant which is mostly produced by mankind, who generates more than 70% of its total volume. The toxic effect of carbon non oxide arises from the fact that it combines with the red blood cells pigment haemoglobin so as impedes the combination that normally occurs in the lungs of oxygen with haemoglobin.
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It thus arrests the transport of oxygen through the blood and leads to symptoms similar to those occur in suffocation. Carbon monoxide has a 500 times greater affinity to bind with haemoglobin than oxygen. No person should be exposed to carbon monoxide at a concentration greater than 35ppm.