Physical and chemical properties of cigarette, heated tobacco and e-cigarette aerosols

Transcription

1 SPS3 N2ff Physical and chemical properties of cigarette, heated tobacco and e-cigarette aerosols Caner U Yurteri, Jennifer Margham, Kevin McAdam, Mark Forster, Chuan Liu, Chris Wright, Derek Mariner, Chris Proctor and John McAughey EAC 2017 Special Session #3: Electronic Cigarettes Scientific Evidence Zürich, CH, Thursday 31 st August

2 Outline significant consumer-led growth for e-cigarettes over last 5 years diversity of products, now including tobacco heating products significant regulatory diversity as tobacco, consumer or pharmaceutical products in some cases prohibited or unregulated internal stewardship process products designed with appropriate stewardship; including assessment of chemical and physical emissions

3 Product categories

4 Product DIVERSITY The era of next generation nicotine delivery products

5 Approaches to modified risk assessment

6 Stewardship process Ingredient exclusion criteria : Non-threshold carcinogens Mutagens Genotoxicants Reproductive and developmental toxicants Respiratory sensitisers REACH List for Substances of Very High Concern Toxicological assessment of ingredient and any reaction / thermal breakdown products Toxicological Thresholds of Concern Approach 1.5 µg/day Costigan & Meredith (2015) Reg. Tox. Pharm. 72(2): Costigan & Lopez-Belmonte (2017) Reg. Tox. Pharm. 87: 1-8

7 Chemical characterisation 7

8 Are all aerosols the same? All are condensation aerosols Tobacco o C Tobacco < 250 o C Heat glycerol, PG, H 2 O, nicotine, < 250 o C Product of heating a material to form a vapour which supersaturates in air Mechanistically similar Physically and visually similar Compositionally and chemically very different

9 Chemical characterisation Untargeted emissions - GC x GC TOFMS analysis 3R4F mainstream cigarette smoke Chemical complexity changes across product categories Key activity is ID of new emissions and associated toxicological assessment *These qualities do not necessarily mean this product produces less adverse health effects than other tobacco products

10 Chemical characterisation Targeted emissions e.g. Vype epen2 Toxicants listed by regulators Other constituents of interest Of 142 constituents tested, most cigarette constituents were not detected in e-cigarette aerosol. Of those detected or quantified, a high proportion were attributable to laboratory air

11 Comparison between Vype epen and 3R4F 142 substances tested in aerosol and smoke On a per-puff basis the following reductions were observed. Such low abundances in e-cigarette aerosol present significant technical challenges to (a) measurement and (b) ensuring a clean chemical background *These qualities do not necessarily mean this product produces less adverse health effects than other tobacco products Margham et al (2016) Chem. Res. Toxicol. 29: Forster et al (2017) Reg. Tox. Pharm., submitted 11

12 Physical characterisation 12

13 Physical characterisation Common puff & dilution engine for constant volume sampling (Cambustion SCS) Electrical mobility spectrometry : Cambustion DMS-500 Laser diffraction : Malvern Spraytec Cascade impaction : Dekati ELPI Multi-l light scattering : Envirometrix

14 Sampling & measurement issues Aerosol is sub-micron cross-over region for choice of optimal techniques Aerosol is semi-volatile minimise dilution awareness of condensation drop-out Aerosol is concentrated minimise transit time to minimise coagulation Aerosol is transient and dynamic (2-3s puff) appropriate time resolution for instrument of choice Cambustion DMS-500 generally preferred choice for cigarette smoke Malvern Spraytec generally preferred choice for THP/ e-cigarettes

15 Particle / droplet diameter Product 3R4F Ref Cigarette glo THP ifuse Hybrid TP Vype epen2 Mobility MMD (nm) 272 ± ± GSD 1.42 ± ± Vype Pebble Optical Dv 50 (nm) ± ± ± ± 90 GSD ± ± ± ± 0.16 Cigarettes / glo smoked to 55/2/30; others to 55/3/30

16 Measurement summary Data for novel device aerosols are broadly similar at approx. 600 nm (optical) Larger than cigarette smoke, but sub-micron and respirable Higher humectant (e.g. glycerol) in novel device formulations more likely to show evaporative losses with DMS-500, where operation is at reduced pressure Geometric standard deviations consistent with other condensation aerosols

17 Summary Increasing number of nicotine delivery platforms / devices worldwide with significant consumer demand Principal mode of aerosol generation remains condensation aerosols Aerosols physically similar that is, respirable Aerosols chemically diverse lower heating modes reduce complexity and toxicant formation Regulatory landscape varies widely Many potential issues can be addressed by appropriate product stewardship, including design, materials, emissions testing, in vitro toxicology testing, in-use studies Longer timescale required to fully address individual and population risk assessment As aerosol scientists we should be contributing to scientific understanding of emerging issues and risk assessment

18 Thank you