Table 3. Metals in e-cigarette aerosol.

	Calcium	Copper	Iron	Magnesium	Silicon
Sub-ohm: 0.2 Ω 49.2 W 150 puffs (mg/L) a	0.409 ± 0.002	0.011 ± 0.001	0.0051 ± 0.0003	0.017 ± 0.002	0.166 ± 0.005
NIOSH: Daily exposure limits (mg/L)	5	1	5	15	5

^a The concentrations of the metals (mg/L) are shown as (mean ± S.D.).