Abstract
INTRODUCTION: Although e-cigarettes share common features such as power units, heating elements and e-liquids, the variability in design and possibility for customization represent potential risks for consumers. A main health concern is the exposure to carbonyl compounds, which are formed from the main components of e-liquids, propylene glycol and glycerol, through thermal decomposition. Levels of carbonyl emissions in e-cigarette aerosols depend, amongst others, on the power supplied to the coil. Thus, e-cigarettes with adjustable power outputs might lead to high exposures to carbonyls if the users increase the power output excessively. The aim of this work was to elucidate the generation of carbonyls in relation to undue battery power setting. METHODS: Carbonyl emissions were generated by two modular e-cigarettes equipped with two atomizers containing coils of different resistance following the ISO 20768:2018 method. The battery power output was increased from the lower wattage level to above the power range recommended by the producer. Carbonyls were trapped by a 2,4-dinitrophenylhydrazine (DNPH) solution and analysed by LC-MS/MS. RESULTS: The amount of carbonyl emissions increased with increasing power setting. An exponential incline was observed when the applied power level exceeded the recommended power range. Exceeding the recommended power range by just 5 watts resulted in up to twenty times the amount of carbonyls emitted at the recommended upper power level. Generation of acetaldehyde and acrolein next to other carbonyls was prominent at high power outputs. CONCLUSIONS: E-cigarettes with customisable power setting might generate high amounts of carbonyls if the battery power output is set by the consumer to levels above the recommended range. This represents a high risk of exposure to carbonyls and thus should be avoided by integrating safety features in e-cigarette devices to limit the possible power settings to the range specified by the manufacturer.