Indexes of tobacco smoke contribution to environmental particulates based on molecular fingerprints of alkanes
Abstract Tobacco smoking is a very common habit and causes the spreading into the atmosphere of a number of toxicants, which heavily affect also health of no smokers. Hence, chemical, physical and toxicological features of smoking products (vapours as well as mainstream, sidestream and third hand smoke) have been extensively investigated. In particular, attention has been paid to organic compounds (individuals, or in combination giving raise to peculiar molecular fingerprints), potentially suitable to act as “chemical signature” of tobacco smoke (TS). At this regard, the signature of long-chain iso and anteiso alkanes has known since long time as typical of TS. Nevertheless, until now no indexes have been identified as suitable to estimate the contribution of TS to environmental pollution, e.g. the TS percentage in carbonaceous aerosol as well as in settled dusts, nor in the respective organic fractions. This paper describes the results of an extensive investigation conducted on non-polar lipid fraction of soot and dust collected in interiors and outdoors. Six potential quantities associated to iso, anteiso and normal C29-C34 alkanes were tested, and finally a cumulative index (TSI) was defined through averaging the three most promising ones in order to estimate TS contribution to organic particulate. The behaviour of TSI was plotted vs. a further parameter, i.e. the exceedance of normal C31 alkane with respect to average of C29 and C33 homologues, revealing a link in the case of aerosols but not of dusts. According to back analysis carried out on several sets of particulate matters, traces of TS seemed to affect even rural areas, while inside smokers’ homes the contributions of TS to PM could account for up to 12.3% and 3.2%, respectively, in aerosols and dusts. This suggests the importance of further investigations aimed at assessing the potential risk for humans associated to tobacco smoking, by means of reliable TS indexes.