This would certainly put a massive amount of carcinogenic hydrocarbons in the air for some time.

And wood-burning stoves by their very nature discharge smoke that contains carcinogenic hydrocarbons.

"A carcinogenic hydrocarbon, benzo (a) pyrene, is partially isolated from leaf and smoke," it said.

Kaufman also published a landmark paper in 1980 in which she described a new theoretical method for coding and retrieving certain carcinogenic hydrocarbons.

Such studies of heteroatomic polynuclears led him to propose a "newer picture" of a carcinogenic hydrocarbon, helping the generalise the classical K-region hypothesis.

A state of emergency was declared by Tehran's Environmental Protection organisation as the density of carcinogenic hydrocarbons climbed to 66 times permissible levels, and those of nitrogen oxides to 23 times permissible levels.

While the European Food Safety Authority has found that some liquid smoke products contain genotoxic compounds, one academic study suggests that the concentration levels of carcinogenic hydrocarbons such as benzo(a)pyrene are under the acceptable limit suggested by the FAO and WHO.