Metal concentrations of e-cigarette liquid and aerosol samples across the different generation devices

摘要

Background: Toxic metal concentrations have been detected in the aerosol of electronic cigarettes (e-cigarettes); however, metal concentrations by device type (generation) have not been described. We investigated metal transfer from e-liquid to aerosol, and compared among different device types. Methods: We sampled 138 e-cigarette devices: 20 first-generation (cig-a-likes), 109 2nd or 3rd generation devices (MODs), and nine 4th generation devices (PODs), including Juul. Samples from the refilling dispenser/cartridge, aerosol, and remaining e-liquid in the tank (MODs only) were obtained. Metals were measured using ICP-MS and reported as mass fractions (ug/kg) in liquids. Results: The median (IQR) concentrations (u.g/kg) measured in the aerosol of MOD devices were 62.3 (8.00, 309) for Ni, 13.1 (3.74, 41.4) for Cr, 9.99 (2.70, 34.7) for Pb, 2.81 (0.90, 9.50) for Mn; in aerosol of POD devices we found 42.0 (27.0, 421) for Ni, 10.3 (8.40, 13.2) for Cr, 4.40 (2.75, 217) for Pb, 2.30 (1.45, 3.00) for Mn. Cig-a-likes and PODs had lower mean concentrations (80% and 50%, respectively) of Ni, Cr, Pb, Mn in aerosol compared to the mean concentrations in the dispenser (p-values <0.005). MODs, however, had 90% higher mean concentrations in the aerosol for all metals compared to the dispenser, and 375% higher in the tank compared to the aerosol (p-values 300% higher in MODs and PODs than cig-a-likes. These results demonstrate that all e-cigarettes are a potential source of exposure to toxic metals.