CO is
produced by incomplete combustion of fuels.
In
a plentiful supply of oxygen, carbon burns to produce carbon dioxide.
If there is insufficient oxygen, carbon monoxide is produced instead of
carbon dioxide.
plenty of oxygen insufficient oxygen
C (s) + O2(g) à CO2(g) 2C (s) + O2(g) à 2CO(g)
About 1014 g of CO is
produced in the United States per year (mostly from
automobiles).
Carbon monoxide is an remarkably toxic gas.
If the concentration of carbon monoxide in
the atmosphere exceeds 0.4 % it is lethal
to humans!