I don't think the problem is with carbon monoxide. Not enough fuel, and too clean burning, and symptoms with carbon monoxide poisoning would be lack of oxygen to the brain, not throat and lung irritation. Potential problems with alcohol fuels involving inhalation would be stuff other than methanol or ethanol or isopropanol that might be in the fuel, such as petroleum distilates and stuff. Also, if you had galvanized steel and some other metals in your stove design that has some potential also for causing irritation problems. All fumes can be nasty, but some more nasty than others. If it doesn't feel good for you, it probably isn't. I love wood smoke though, even though its not good for you either, and again some worse than others