A new paper examining whether heated tobacco products emit smoke has been published in the academic journal American Chemical Society Omega.
Professor Colin Snape and Dr Clement Uguna, in the Faculty of Engineering at the University of Nottingham, have conducted a literature review of the studies that investigate the emissions generated by heated tobacco products (HTPs).
HTPs, which are often viewed as an alternative to cigarettes, are electronic devices that heat a rod or stick containing cast tobacco sheet, or reconstituted tobacco made from ground tobacco powder prepared with ingredients such as glycerol, water, cellulose fibre, and guar gum to produce vapours. Hybrid HTP devices generate nicotine aerosols by heating an e-liquid and passing the vapour through a capsule of tobacco.
The academics found that, from the materials reviewed, the chemical evidence to date indicates that these devices generate Harmful and Potentially Harmful Constituents (HPHC) and other compounds that are linked to concerns regarding human health.
The study suggests that the emissions from heated tobacco products contain the same HPHCs as released in cigarette smoke and, in terms of their temperature of release, they do fit the definition of smoke, containing compounds such as levoglucosan that are markers of biomass combustion and black carbon that are associated with biomass, wood and tobacco smoke.
Professor Snape and Dr Uguna, experts in pyrolysis and hydropyrolysis (the heating of materials to convert to liquid or gas), received funding for this study from STOP, a global tobacco industry watchdog.
While the literature does point to heated tobacco products emitting smoke and other chemicals - less than cigarettes - there is much more work to be done to understand this phenomenon more clearly.
"Analysis after repeated use needs to be investigated to provide more reliable assessments of the compounds released from the devices in relation to human use, as recommended by their respective manufacturers, before cleaning the device," he added.
The Tobacco Control Research Group (TCRG) at the University of Bath is a partner in STOP. Commenting on the findings, Director of TCRG Professor Anna Gilmore said: "This new paper raises significant questions about manufacturers' definitions of "smoke-free" and whether these definitions can be backed up by science. It's clear that more independent research is needed so that policy makers and consumers understand fully the potential harms of using these products."
