Table 1

Comparison of device geometry, electrical characteristics, liquid composition and nicotine, and carbonyl emissions, mean (SD), of new and old technology JUUL pods procured in the UK in July 2020

JUUL‘new technology’ JUUL
Coil dimensions
Coil wire diameter (mm)0.130.13
Coil wire length (mm)26.826
Number of coils11
Electrical characteristics
Max puff duration (s)5.95.9
Pod resistance (Ω)1.71.7
Computed resistivity (Ωm)8.4×10−7 8.67×10−7
Voltage (V)1–2.52.5–2.8
Computed power range (W)0.6–3.73.6–4.5
Liquid composition
Nominal nicotine content (mg/mL)2018
Measured nicotine content (mg/mL)18.33 (1.55)18.18 (0.45)
% Protonated91.97 (3.57)92.45 (3.23)
pH6.59 (0.14)6.19 (0.11)*
% Propylene glycol26.2 (0.45)27.6 (0.55)*
% Vegetable glycerin73.8 (0.45)72.4 (0.55)*
Emissions in 15 puffs
Total particulate matter (mg)41.66 (3.99)59.7 (14.02)*
Nicotine (mg)0.47 (0.1)0.73 (0.18)*
Carbonyl compounds (µg)
 Formaldehyde0.6 (0.27)0.29 (0.03)
 Acetaldehyde0.96 (0.19)0.79 (0.05)
 Acetone4.13 (0.39)4.63 (0.19)*
 AcroleinNDND
 Propionaldehyde0.04 (0.03)0.03 (0.02)
 Crotonaldehyde0.03 (0.05)0.11 (0.06)
 Methacrolein0.49 (0.08)0.6 (0.07)
 ButyraldehydeNDND
 Valeraldehyde0.29 (0.1)0.33 (0.07)
 GlyoxalNDND
 Methylglyoxal0.86 (0.51)0.95 (0.06)
 Total carbonyls7.41 (1.23)7.73 (0.26)
  • *Represents a significant difference between the new and previous technology JUUL pods (p<0.05).