Assessing the impact of device parameters on electronic cigarette aerosol dynamics: Comprehensive analysis of emission profiles and toxic chemical constituents.

The toxicity of electronic cigarette (EC) aerosol is influenced not only by the type of e-liquid but also by various operational parameters of the device used to vaporize it. In this study, we utilized a flask and heating mantle system, instead of a conventional EC device, to systematically evaluate the effects of EC device operational parameters, including vaporization temperature, airflow rate, and the materials of coils and wicks, on the generated mass of EC aerosol and the production of toxic carbonyl compounds. The results demonstrated that these parameters significantly impact aerosol mass and toxicant composition. Specifically, increasing vaporization temperature and airflow rate drastically affect aerosol mass, showing exponential and logarithmic increases. Using the ISO 20768 method, aerosol mass (from 20 μL e-liquid) escalated over threefold from 3100 μg at 200°C to 10,300 μg at 400°C, illustrating temperature's pivotal role. Formaldehyde levels rose from 0.21 μg to 60.2 μg with temperature increases from 200°C to 400°C. At a realistic vaporization temperature of 300°C, the formaldehyde mass was 2.21 μg (3.28 ppm), exceeding the lowest-observed-adverse-effect level for acute respiratory toxicity in humans. While cotton wicks modestly affected aerosol mass, they significantly raised formaldehyde and acetaldehyde levels by 36.2%. In contrast, silica, kanthal, and nichrome materials increased aerosol mass and chemicals like propylene glycol, vegetable glycerin, nicotine, formaldehyde, and acetaldehyde by 22.7% to 63.2%. Our findings underscore the urgent need for regulations encompassing e-liquids and EC devices to mitigate health risks associated with EC use, providing a scientific basis for safety-focused regulatory measures.