Indexes of tobacco smoke contribution to environmental particulates based on molecular fingerprints of alkanes.

Tobacco smoke (TS) is the source of a number of toxicants affecting the atmosphere and poses a threat to smokers and the whole community. Chemical, physical and toxicological features of smoking products (vapours as well as mainstream, side stream and third hand smoke) have been investigated extensively. Special attention is paid to organic compounds (individually or in combination giving raise to peculiar molecular fingerprints), potentially able to act as “chemical signature” of TS. At this regard, the percent distribution of long-chain normal , iso and anteiso alkanes was ascertained as typical of TS. Nevertheless, until now no indexes have been identified as suitable for assessing the global TS contribution to environmental pollution, e.g. the TS percentage in carbonaceous aerosol and in deposited dusts, the only exception consisting in the use of nicotelline as tracer. This paper describes the results of an extensive study aimed at chemically characterizing the non-polar lipid fraction associated to suspended particulates (PMs) and deposition dusts (DDs) collected at indoor and outdoor locations. Based on the iso , anteiso and normal C 29 -C 34 alkane profile in the samples as well in tobacco smoke and no-TS related emissions (literature data), various parameters describing the distribution of compounds were investigated. Finally, a cumulative variable was identified as tobacco smoke impact index (TS%) suitable for estimating the TS percentage occurring in the particulate matter. The TS% rates were plotted vs. the exceedance of normal C 31 alkane with respect to average of C 29 and C 33 homologues, which results higher in TS than in most other emissions, revealing a link in the case of suspended particulates but not of deposited dusts. According to back analysis carried out on all particulate matter sets, it was found that traces of TS affect even remote areas, while inside the smokers’ homes the contributions of TS to PM could account for up to ~61% and ~10%, respectively, in PM and DD. This confirms the need of valuing the health risk posed by TS to humans, by means of tools ease to apply in extensive investigations.