Again, when you see a smoker, of course you evaluate him and you ask him how many cigarettes he smokes. To give you a proper idea of the number of cigarettes he smokes, we measure his alveolar CO. If somebody comes out of the clinic with CO of 12 ppm or 18 ppm he will not be given the same concentration as somebody who comes in with 45 ppm CO in his alveolar air. You know that from the rules in the workman's compensation board, if you go over 50 ppm in a shop the CSST would close the shop.
On November 6th, 2014. See this statement in context.