“…Breath carbon monoxide (CO) is a biochemical marker of recent cigarette smoking (see Bittoun, 2008; Society for Research on Nicotine and Tobacco Subcommittee on Biochemical Verification, 2002). Breath CO correlates well with other established assays of cigarette smoking, such as COHb concentration in blood samples (Hald, Overgaard, & Grau, 2003;Jarvis, Belcher, Vesey, & Hutchison, 1986), and urinary cotinine levels (Marrone, Paulpillai, Evans, Singleton, & Heishman, 2010;Marrone et al, 2011), and has high levels of sensitivity and specificity in distinguishing between cigarette smokers and non-smokers (Javors, Hatch, & Lamb, 2005;MacLaren et al, 2010;Perkins, Karelitz, & Jao, 2013;Raiff, Faix, Turturici, & Dallery, 2010).…”