And in fact, carbon monoxide is about 250 times as likely to actually bind to hemoglobin than oxygen. And what that means is when we we have oxygen, carbon monoxide, and hemoglobin present in the same mixture, carbon monoxide will have no problem out competing the oxygen for that heme group on hemoglobin. On top of that, when carbon monoxide actually binds onto hemoglobin, because of its very high affinity, it's very difficult to actually displace and release the carbon monoxide from hemoglobin. Now, the question is, how exactly does the binding of carbon monoxide onto hemoglobin affect the oxygen hemoglobin dissociation curve? So, to see what the effect is, let's take a look at the following diagram. So, as always, the Y axis is the percentage saturation of hemoglobin inside our blood plasma, and it ranges from zero to 100%.