iQOS: evidence of pyrolysis and release of a toxicant from plastic

Abstract

ObjectiveTo evaluate performance of the I quit original smoking (iQOS) heat-not-burn system as a function of cleaning and puffing topography, investigate the validity of manufacturer’s claims that this device does not burn tobacco and determine if the polymer-film filter is potentially harmful.MethodsiQOS performance was evaluated using five running conditions incorporating two different cleaning protocols. Heatsticks were visually and stereomicroscopically inspected preuse and postuse to determine the extent of tobacco plug charring (from pyrolysis) and polymer-film filter melting, and to elucidate the effects of cleaning on charring. Gas chromatography–mass spectrometry headspace analysis was conducted on unused polymer-film filters to determine if potentially toxic chemicals are emitted from the filter during heating.ResultsFor all testing protocols, pressure drop decreased as puff number increased. Changes in testing protocols did not affect aerosol density. Charring due to pyrolysis (a form of organic matter thermochemical decomposition) was observed in the tobacco plug after use. When the manufacturer’s cleaning instructions were followed, both charring of the tobacco plug and melting of the polymer-film filter increased. Headspace analysis of the polymer-film filter revealed the release of formaldehyde cyanohydrin at 90°C, which is well below the maximum temperature reached during normal usage.DiscussionDevice usage limitations may contribute to decreases in interpuff intervals, potentially increasing user’s intake of nicotine and other harmful chemicals. This study found that the tobacco plug does char and that charring increases when the device is not cleaned between heatsticks. Release of formaldehyde cyanohydrin is a concern as it is highly toxic at very low concentrations.

Informing iQOS Regulations in the United States: A Synthesis of What We Know

“…Research independent from the industry has documented that the aerosols released by iQOS contain many of the same harmful or potentially harmful substances found in cigarettes (e.g., polycyclic aromatic hydrocarbons, carbon monoxide, formaldehyde cyanohydrin, tobacco-specific nitrosamines), as well as 84% of the nicotine found in cigarette smoke (Auer et al, 2017;Bekki et al, 2017;Davis et al, 2019;Leigh et al, 2018;St. Helen et al, 2018;Schaller et al, 2016).…”

Heat-Not-Burn Tobacco Products: The Devil in Disguise or a Considerable Risk Reduction?

“…Limitations in the risk assessment also include substances not currently being analyzed, such as pyrolysis products of plastics and other ingredients and additives unique to HNB (Mallock et al, 2018;Davis, Williams, & Talbot, 2018). The risk assessment also only considers isolated chemical compounds and does not include other acute and chronic effects-for example, respiratory or cardiovascular effects caused by other potential mechanisms such as temperature or other physical effects of the aerosol.…”

Smoking cessation in COPD: confronting the challenge

“…In addition, such studies should include outcome measures related to patient satisfaction with HTPs since, on one hand, while patients might enjoy the similarity of the feel, smell and taste of these products to those of regular cigarettes, on the other hand, they might be annoyed by the need to clean the holder between uses of tobacco sticks, as recommended by the manufacturer, to remove residual fluid and tobacco plug debris from the heater in the device. Failure to adhere to this recommendation could lead to charring of the tobacco plug and melting of the polymer-film filter with release of highly toxic formaldehyde cyanohydrin, as recently reported by Davis et al [24].…”