There is no evidence to support the fact that smoking in cars is 23 times more toxic than in other indoor environments, states an analysis article in CMAJ (Canadian Medical Association Journal) . The article, by Australian researchers, describes how a local media report of an unsourced statistic - that "second-hand smoke was "23 times more toxic in a vehicle than in a home"" - led to widespread reporting of the figure in international media and peer-reviewed literature. However, there appears to be no scientific evidence to support this claim... 
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