Table 1

Topography in e-cigarette users

ReferenceStudy characteristics
Study product/sample Size
Traditional cigaretteUse duration e-cigaretteUse duration traditional cigaretteResults
e-cigarette topography
Traditional cigarette topographyOther topography measures
Etter and Bullen26Varied brandsN/AMean=3 monthsN/A120 puffs/dayN/AN/A
Hua et al28Preferred e-cigarette, flavour, nicotine concentration/64-e-cigarette users; 9 traditional cigarette usersPreferred traditional cigarette flavour, nicotine concentrationAd libitumAd libitumPuff duration 4.3 s, SD  ±1.5; exhalation duration 1.7 s, SD   1.1Puff duration 2.4 s, SD   ±0.8; exhalation duration 1.6 s, SD  0.7Observational data; e-cigarette users showed large variation in puff duration
Farsalinos et al 3eGo-T battery, Epsilon atomiser, Nobacco 9 mg/mL nicotine/45 e-cigarette users; 35 traditional cigarette users2 cigarette cigarettes (brand not identified)Ad libitum for 20 min for experienced users; ad libitum for 10 min for naïve users2 cigarette cigarettes ad libitum, 00.7 mg nicotineE-cigarette user puff duration 4.2±0.7, inhalation 1.3±0.4 s; puff number=43; traditional cigarette users using e-cigarettes puff duration 2.3±0.5, inhalation 2.1±0.4 sPuff duration 2.1±0.4 and inhalation 2.1±0.4 sObservational data; nicotine absorption was not measured
Trtchounian et al14Liberty Stix, Crown Seven Hydro Kit, NJOY, Smoking Everywhere GoldMerit Ultra Lights, Marlboro Ultra Lights, Marlboro Lights, Marlboro Reds, Camel unfiltered, Camel Lights, Camel filtered, Pall Mall unfilteredFirst 10 puffs of an e-cigarette7–11 puffs; puffs were 2.2 s long every minute; 3 seriesAverage vacuums ranged from 25±3 mm H2O to 153±12 mmH2OAverage vacuums ranged from 30 mm H2O±3 to 80 mm H2O±5Machine yield data from non-standardized, non-validated topography equipment
Trtchounian et al14Liberty Stix, Crown Seven Hydro Kit, NJOY, Smoking Everywhere Gold, VapCigsN/AVacuum and aerosol density measured until each cartridge was exhausted, 3 seriesN/AAverage vacuums ranged from 34±6 mm H2O to 174±23 mmH2O; puffs ranged from 177±15 to 313±115.N/AMachine yield data from non-standardized, non-validated topography equipment
Williams and Talbot30*Liberty Stix #1, Liberty Stix #2, VapCigs, Crown Seven Hydro Imperial, Smoking Everywhere PlatinumN/AFirst 10 puffs of an e-cigaretteN/APressure drop, flow rate and aerosol density remained constant for a given e-cigarette but varied among brands. Liberty Stix had the lowest pressure drop (20 mm H2O) and Liberty Stix #2 had the highest pressure drop (150 mm H2O)N/AMachine yield data from non-standardized, non-validated topography equipment
Williams and Talbot30*VapCigs #2, Crown Seven Hydro Imperial, Smoking Everywhere PlatinumN/AAerosol density measured until each cartridge was exhausted, 3 seriesN/APuffs ranged from 160±6 to 400±10.N/AMachine yield data from non-standardized, non-validated topography equipment
Williams and Talbot30*Liberty Stix #1, Liberty Stix #2N/A11 puffs, 3 seriesN/AAerosol density remained similar for the first e-cigarette so performed quite uniformly from trial to trial. In contrast, pressure dropped significantly during trial 3 for the second cigarette with a drop in aerosol densityN/APressure drop was consistent for Liberty Stix #1 so performed uniformly; Liberty Stix #2 did not perform uniformly; machine yield data from non-standardized, non-validated topography equipment
  • *One Liberty Stix and one VapCigs e-cigarette from prior study (Trtchounian et al14) were included in this study. The original purchases are designated Liberty Stix #1 and VapCigs #1; the purchases used only in this study are designated Liberty Stix #2 and VapCigs #2.