So the CO2, because it's produced in very small amounts in our body, does not actually affect the hemoglobin in any adverse way. But we produce carbon monoxide in much greater concentrations via different types of processes that take place outside our body. For example, cars produce CO2, and smoking also produces CO2. So carbon monoxide, as it turns out, is actually a competitive inhibitor of hemoglobin, and it competes with oxygen. And in fact, it is 250 times more likely to actually bind to the heme group of hemoglobin than oxygen. Now, by binding to hemoglobin, the carbon monoxide creates a conformational change that ultimately increases the affinity of hemoglobin for oxygen.