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) | 0.13 | 0.13 |
| Coil wire length (mm) | 26.8 | 26 |
| Number of coils | 1 | 1 |
| Electrical characteristics | ||
| Max puff duration (s) | 5.9 | 5.9 |
| Pod resistance (Ω) | 1.7 | 1.7 |
| Computed resistivity (Ωm) | 8.4×10−7 | 8.67×10−7 |
| Voltage (V) | 1–2.5 | 2.5–2.8 |
| Computed power range (W) | 0.6–3.7 | 3.6–4.5 |
| Liquid composition | ||
| Nominal nicotine content (mg/mL) | 20 | 18 |
| Measured nicotine content (mg/mL) | 18.33 (1.55) | 18.18 (0.45) |
| % Protonated | 91.97 (3.57) | 92.45 (3.23) |
| pH | 6.59 (0.14) | 6.19 (0.11)* |
| % Propylene glycol | 26.2 (0.45) | 27.6 (0.55)* |
| % Vegetable glycerin | 73.8 (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) | ||
| Formaldehyde | 0.6 (0.27) | 0.29 (0.03) |
| Acetaldehyde | 0.96 (0.19) | 0.79 (0.05) |
| Acetone | 4.13 (0.39) | 4.63 (0.19)* |
| Acrolein | ND | ND |
| Propionaldehyde | 0.04 (0.03) | 0.03 (0.02) |
| Crotonaldehyde | 0.03 (0.05) | 0.11 (0.06) |
| Methacrolein | 0.49 (0.08) | 0.6 (0.07) |
| Butyraldehyde | ND | ND |
| Valeraldehyde | 0.29 (0.1) | 0.33 (0.07) |
| Glyoxal | ND | ND |
| Methylglyoxal | 0.86 (0.51) | 0.95 (0.06) |
| Total carbonyls | 7.41 (1.23) | 7.73 (0.26) |
*Represents a significant difference between the new and previous technology JUUL pods (p<0.05).