We link to a paper at our new Scientific Portal.
This 1993 paper, “Relevance of nicotine content of common vegetables to the identification of passive smokers,” demonstrates that nicotine is so common everybody is exposed to it. Thus determination of “exposure” to passive smoking via testing of blood cotinine/nicotine level is effectively bogus.
What is even more bogus, however, is the idea behind such testing, that exposure to passive smoking equals risk. The measure used is bogus, but even if it weren’t, the mere existence of traces of tobacco smoke in the air is no evidence whatsoever of risk. “Passive smoking” in any quantity has never been demonstrated as a risk. Thus the whole exercise of attempting to measure exposure is an exercise in futility in the first place.
The link below connects to our portal presentation with access to the original study.