They are in a sort of elevated stress condition. And the older they get the more obvious these changes are. In a young population, you see very little difference between smokers and nonsmokers in these stress markers. The longer people continue to smoke, the more evidence you find of changes suggesting that their body is in an activated stress situation. When there is stress present in the tissues, low levels of inflammatory damage are likely.
Inflammatory damage can release iron.
Iron is a pro-oxidant. I don't know the answer to these questions. I recently drew attention to the similarity between plasma vitamin C and beta-carotene in response to diet, sex, smoking, and disease. In the case of vitamin C, the behavior in stress suggests that it is a pro-oxidant. Furthermore, we know that if you give large amounts of vitamin C to people with hemolytic disorders you will in fact cause hemolysis.