Zoology - Breathing and Exchange of Gases Question with Solution | TestHub

Cigarette smoke contains a high concentration of CO and smokers are exposed to an estimated 400-500 ppm CO while smoking and consequently have much higher COHb. A necessary consensus, given the variability level of COHb due to environmental CO, suggests an absolute upper limit of normal COHb of 3 % for non-smokers and 10 % for heavy smokers