Table 2.

Daily metal inhalation by e-cigarette vaping (DMIE) and calculated daily exposure limits (DELs) for 14 metals.

Element	NIOSH:REL (µg/m3)	Calculated DEL (µg) 1	Daily Metal Inhalations by E-Cigarette (DMIE) (µg) 2				DMIE/DEL (%)
			20 W	40 W	60 W	80 W	20 W	40 W	60 W	80 W
Ag	10	67	<LOD 3	<LOD	<LOD	<LOD	0	0	0	0
Al	5000	33,500	0.007	0.033	0.036	0.059	<0.001	<0.001	<0.001	<0.001
As	10	67	0.084	0.239	0.451	0.791	0.125	0.357	0.673	1.18
Cd	5	33.5	0.097	0.183	0.23	0.326	0.289	0.547	0.687	0.973
Co	50	335	<LOD	<LOD	<LOD	<LOD	0	0	0	0
Cr	500	3350	8.577	22.5	32.4	50.49	0.256	0.672	0.967	1.507
Cu	1000	6700	0.307	0.61	0.964	2.969	0.005	0.009	0.014	0.044
Fe	5000	33,500	1.672	4.068	6.343	10.88	0.005	0.012	0.019	0.032
Mg	10,000	67,000	1.399	1.485	2.177	4.492	0.002	0.002	0.003	0.007
Mn	1000	6700	<LOD	<LOD	<LOD	<LOD	0	0	0	0
Ni	15	100.5	0.126	0.214	0.347	0.599	0.125	0.213	0.346	0.596
Pb	50	335	0.093	0.184	0.281	0.386	0.028	0.055	0.084	0.115
Sb	500	3350	<LOD	<LOD	<LOD	<LOD	0	0	0	0
Zn	5000	33,500	2.811	4.035	9.064	9.589	0.008	0.012	0.027	0.029

¹ Calculated DEL = (NIOSH: REL) × (moderate activity inhalation rate, 0.83 m³/h) × (time-weighted average, 8 h). ² DMIE = (metal release per puff) × (number of median daily e-cigarette puffs, 140 puffs). ³ <LOD: Lower than the limit of detection of ICP-MS (2.5 ppb).