Re: natural bbq coals
I don't know about the VOCs in barbecue charcoal. There really is no such thing as a "pure carbon" fuel. All these fuels, petroleum-based or man-made with compressed vegetable matter, are long strings of carbons. For any carbon in the middle, there will be two hydrogens attached and a carbon on an end will have three. Energy comes from breaking the carbons apart and stripping them of their hydrogen. The byproducts are H2O, CO, and CO2 as well as an aerosol of particulates. Shorter carbon trains are "volatile organic compounds"--an example of this is gasoline. As they get longer, they becomes heavier and lose this trait and eventually become solid.
I find the topic of coals interesting since there seems to be very little conclusive information about them and the differences between various products. What shishaholic said about briquettes for hookahs and BBQ being heated to different temperatures may be true; the effect this has on how it burns is something worth discussing. I also am unsure about qualitative differences between "quicklites" and normal charcoals, since I would expect a quicklite is wholly normal coal on the inside with a layer of accelerant on the outside to get it started.
One thing that is for certain is burning charcoal the way we do, with a smoldering ember, is a textbook example of incomplete combustion. The result of incomplete combustion is carbon monoxide (it takes more energy to create carbon dioxide). All coals will produce a significant amount of carbon monoxide. CO isn't a big issue, however, until you inhale it in large quantities for extended periods of time. Whether CO can build up from a single charcoal to dangerous levels in an ordinary closed room is worth exploring.