Assessment and characterization of emerging contaminants in aerosols from novel tobacco products: Emphasis on glycidol, chloropropanol, and potential exposure biomarkers

Abstract

Despite assertions that novel tobacco products, including heated tobacco products (HTPs) and electronic cigarettes (ECs), contain reduced hazardous substances and are marketed as safer alternatives to traditional cigarettes, they present new challenges. The aerosolization process of components such as glycerol and propylene glycol generates emerging carcinogenic contaminants, specifically glycidol and chloropropanol, which pose significant health risks. To address the insufficient evaluation criteria for carcinogenic contaminants produced by these novel tobacco products, we developed a novel method for the simultaneous quantification of glycidol and chloropropanol. This study investigated the effects of operational variables, including temperature and power settings within the atomization region of the device, as well as the composition of the electronic cigarette liquid, on the emissions of glycerol and chloropropanol. Our findings demonstrate that emissions of both glycerol and chloropropanol increased with elevated device temperatures and power levels, with a stronger correlation observed for glycerol compared to propylene glycol. Furthermore, the research indicated that sucralose is not the only chlorine source contributing to the formation of chloropropanol. Furthermore, the metabolites of chloropropanol—a class 2B carcinogen—in aerosols derived from ECs remain largely unknown. This study employed animal models and population-based experiments to investigate the in vivo metabolic processes of glycidol and chloropropanol. The findings revealed that 2,3-dihydroxypropylmercapturic acid (23HPMA), a metabolite formed from both compounds, may be a valuable biomarker for assessing exposure to novel tobacco products. Our research provides a robust analytical framework for detecting these contaminants in aerosols from novel tobacco products and highlights the significant influence of device settings and e-liquid composition on compound emissions, emphasizing the necessity for thorough safety evaluations. Additionally, this study offers evidence for identifying exposure biomarkers generated from the metabolism of emerging contaminants, particularly chloropropanol, in the human body.