I believe there is a BIG misconception about BBQ coal (and coal in general).
1st of all read this to clear out what charcoal is http://www.howstuffworks.com/question43.htm
2nd there are many kinds of BBQ charcoal.
Natural BBQ charcoal usually heated (at the absence of oxygen)@ about 500C'
Briquettes from the same proccess but have starting agents on them
AND shisha charcoal is heated (again at the absence of oxygen) @ at a much higher temp and for longer so ALL the volatile hydrocarbons and water from the wood avaporates and pure carbon and ash is left. Ash which is minerals such as calcium and potasium which do not burn. Whats left is carbon reacting with oxygen producing CO.
FACT: THERE IS NO COAL THAT DOES NOT PRODUCE CO