Burning a
cigarette is actually a very
complex process, from a scientific standpoint at least. A great number of
chemical reactions occur, due to the physical processes involved in the
combustion. Basically however the burning zone in the cigarette can be divided into two
regions :-
1. The combustion zone. In this zone
oxygen reacts with
carbonised tobacco, releasing simple gasses like
carbon dioxide,
carbon monoxide and
hydrogen. The burning process is fairly
efficient, and temperatures here can reach 700-950
centigrade.
2. The pyrolysis/distillation zone. Just behind the combustion zone is where the interesting
chemistry goes on. Here the oxygen content is too low to give complete combustion, but the
temperature is still high enough (200-600
o) to support a
myriad of chemical reactions. About one third of the final smoke components
distil out of the tobacco here.
What results is a
super-saturated vapor which within a couple of milliseconds,
condenses into the
aerosol of
ash particles that makes up the visible
smoke. About 4800 different consituents have been found in cigarette smoke, including some
metals that were present in the tobacco plant. Most of these substances are probably
bad for you. Although some of the chemicals produced may, in fact, have some
anti-cancer properties.