Abstract

Electronic cigarettes (E-cigarettes) generate an aerosol that contains metals. Little is known about the effects of device type and vaping patterns on metal exposure. The objectives of this study were (1) to quantify concentrations of 14 metals in aerosol generated by four types of e-cigarettes including two mods (Istick 25 and SMOK) and two pods/cigalikes (BLU and JUUL) and (2) to examine the effects of device type, device power, flavor (tobacco, menthol, fruit, and others), nicotine content, and coil aging on metal emissions. The mods were operated at three power settings. Two new and two used coils were used to examine the effects of coil variability and aging with pale whale flavored e-liquid. In total, 160 aerosol samples were obtained and analyzed. Median metal concentrations (µg/kg) in aerosol generated by each of the two mods were: 3.02 and 20.8 for Cr, 134 and 542 for Cu, 118 and 153 for Fe, 19.6 and 64.0 for Mn, 862 and 2,252 for Ni, 123 and 541 for Pb, 318 and 20.9 for Sn, 3,432 and 3,114 for Zn. Median metal concentrations (µg/kg) in pods/cigalikes were markedly lower than in mods: 0.39 and 0.41 for Cr, 31.0 and 6.02 for Cu, 0.08 and 0.08 for Fe, 0.80 and 0.39 for Mn, 1.32 and 11.9 for Ni, 6.88 and 0.88 for Pb, 0.80 and 0.01 for Sn, 1,247 and 683 for Zn. Metal concentrations depended on power, flavor, nicotine content, and coil age. Device type and vaping patterns had great impact on the levels of harmful metals in the aerosol. Aerosolized metal exposure from e-cigarettes can potentially be reduced though not eliminated if strict e-cigarette manufacturing standards are established.