Electronic cigarettes: overview of chemical composition and exposure estimation

Table 4 Overview about constituents in electronic cigarettes with descriptive statistics and best fit distributions

Agent	Positive samples	Mean	Median	Standard deviation	Best fitting risk function for concentration of agent in the beverage^a
Nicotine (mg/ml)	65%	11	6.8	13	RiskNormal(11.023;13.134;RiskTruncate(0;))
Glycerol (g/100 g)	94%	37	35	23	RiskWeibull(1.8104;44.812;RiskShift(−2.8327);RiskTruncate(0;))
1,2-Propanediol (g/100 g)	94%	57	64	30	RiskTriang(−18.939;91.8;100.45;RiskTruncate(0;))
Ethylene glycol (g/100 g)	91%	10	5	18	RiskLoglogistic(−0.40204;5.15;1.8215;RiskTruncate(0;))
1,3-Propanediol (g/100 g)	13%	0.6	0	1.7	RiskResample(2;[all measurements])
Thujone (mg/L)	4%	6.7	0	34	RiskResample(2;[all measurements])
Ethyl vanillin (mg/L)	26%	30	0	68	RiskResample(2;[all measurements])

^aThe best fit distributions were selected based on Kolmogorov-Smirnov statistics. For 1,3-propanediol, thujone and ethyl vanillin, distribution fitting was not possible due to the low incidence. Random resampling is used for these agents from a data table with all measurements where all samples with not detectable concentrations were treated as zero.

ISSN: 1617-9625