In a recently updated survey devised by American political scientist Charles Murray, titled "Do you live in a bubble?", respondents were asked a series of questions about their finances, social and cultural habits to try to determine whether they lived in an upper middle-class, white, urban "bubble".

Have you ever lived on a family income near the poverty line, how often do you eat in a popular chain restaurant or watch a top-rating show like The Big Bang Theory – that sort of thing. One question also probed your proximity to smoking tobacco.

"During the last month, have you voluntarily hung out with people who were smoking cigarettes?" it asked.

Why is this relevant? As Murray explained, "Rates of smoking have a strong socioeconomic gradient, but the wording of the question is designed to get at something else … open smoking in the world of the new upper class has become so rare that it is nearly invisible … it is possible to go for weeks … without smelling a whiff of cigarette smoke anywhere except on a public street."