Table 1.

Differences in toxic compounds in cigarette and e-cigarette smoke [17,18,19].

Toxic Compound Type	Toxic Compound	Concentration Range Cigarette (/Puff)	Concentration Range E-Cigarette (/Puff)
Carbonyls	Formaldehyde	<10 µg	<82 µg
	Acetaldehyde	<140 µg	<53 µg
	Acrolein	<14 µg	<3.3 µg
	Propionaldehyde	<5.9 µg	<1.79 µg
	Crotonaldehyde	<2 µg	<0.04 µg
N-nitrosamines	N’-nitrosonornicotine (NNN)	<370 ng	<0.029 ng
	N’-nitrosoanabasine (NAB)	<15 ng	<0.01 ng
	4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)	<77 ng	<0.019 ng
	N’-nitrosoanatabine (NAT)	<16 ng	<0.085 ng
Volatile organic compounds (VOCs)	Toluene	<6.9 µg	<1.53 µg
	Benzene	<4.5 µg	<0.41 µg
Inorganic compounds	Nickel	<60 ng	<6.4 ng
	Cobalt	<0.02 ng	<0.58 ng
	Chromium	<7 ng	<9 ng
	Lead	<8.5 ng	<3.8 ng
	Cadmium	<35 ng	-
	Zinc	<1370 ng	<458 ng
	Cuprum	<130 ng	<20.9 ng
	Carbon monoxide (CO)	<2.3 mg	-
Polycyclic aromatic hydrocarbons and heterocyclic aromatic hydrocarbons (PAHs)	Benz[a]anthracene	<7 ng	-
	Benzo[b + k]fluoranthene	<3.4 ng	-
	Benzo[a]pyrene	<4 ng	-
	Dibenzo[a, h]anthracene	<0.4 ng	-
Nicotine		<0.3 mg	<0.142 mg
Particulate matter	Total particulate matter (TPM)	<1.7 mg	<5.8 mg