Figure 1

Figure 2

Figure 3

Consuming behavior of the participants_
| Behavior | Ratio (%) | |
|---|---|---|
| Using time | 3–6 months | 15.7 |
| 6–12 months | 30.5 | |
| 1–2 years | 34.8 | |
| 2–3 years | 11.2 | |
| 3–5 years | 4.7 | |
| ≥5 years | 3.1 | |
| EC type | Cartomizer | 2.9 |
| Tank | 96.1 | |
| Disposable | 1.0 | |
| Nicotine concentration | None | 17.2 |
| low (1–5 mg/mL) | 58.3 | |
| mid (6–11 mg/mL) | 15.3 | |
| high (12–20 mg/mL) | 2.7 | |
| ultra high (> 20 mg/mL) | 0.4 | |
| not stated | 6.1 | |
| Battery power (w) | 0–25 | 21.2 |
| 26–50 | 38.3 | |
| 51–75 | 13.8 | |
| 76–100 | 16.3 | |
| 101–150 | 3.1 | |
| > 151 | 7.3 | |
The influence of EC type on the puff parameters_
| Puffing topography | Mean value | Tank | Cartomizer | Disposable |
|---|---|---|---|---|
| Volume (mL) | Average | 88.6 | 57.5 | 57.4 |
| SD | 50.5 | 22.9 | 19.9 | |
| Average flow (mL/s) | Average | 48.0 | 29.5 | 32.2 |
| SD | 19.2 | 10.1 | 18.8 | |
| Peak flow (mL/s) | Average | 69.7 | 39.8 | 46.3 |
| SD | 27.6 | 16.1 | 30.2 | |
| Duration (s) | Average | 1.97 | 1.91 | 1.97 |
| SD | 0.74 | 0.57 | 0.75 | |
| IPI (s) | Average | 22.5 | 10.4 | 10.5 |
| SD | 80.6 | 6.2 | 7.5 | |
| Time of peak flow (s) | Average | 0.87 | 0.84 | 1.04 |
| SD | 0.43 | 0.43 | 0.63 | |
Smoking status of the participants_
| Item | Ratio (%) |
|---|---|
| Exclusive EC users | 26.8 |
| Dual EC users | 73.2 |
| Ex-smokers among exclusive EC users | 80.3 |
| No smoking before EC use among exclusive EC users | 19.7 |
| Smokers before EC using among dual EC users | 88.2 |
| No smoking before EC use among dual EC users | 11.8 |
The influence of nicotine concentrations on the puff parameters_
| Nicotine-free | Low 1–5 mg/mL | Medium 6–11 mg/mL | High 12–20 mg/mL | |
|---|---|---|---|---|
| Volume (mL) | 93.9 | 90.3 | 76.4 | 65.6 |
| Average flow (mL/s) | 47.5 | 49.6 | 42.4 | 34.6 |
| Peak flow (mL/s) | 67.5 | 72.8 | 61.2 | 46.7 |
| Duration (s) | 2.02 | 1.97 | 1.83 | 2.08 |
| IPI (s) | 22.5 | 25.2 | 14.4 | 16.3 |
| Time of peak flow (s) | 0.82 | 0.87 | 0.87 | 1.11 |
Average puffing topography parameters of the participants_
| Puffing topography (average, SD) | Total | Beijing | Shanghai | Guangzhou | Shenzhen |
|---|---|---|---|---|---|
| Volume (mL) | 87.2 (50.1) | 67.5 (38.2) | 78.5 (41.2) | 91.4 (53.9) | 100.4 (54.0) |
| Average flow (mL/s) | 47.3 (19.2) | 43.9 (17.8) | 44.2 (19.2) | 48.6 (19.6) | 50.5 (18.8) |
| Peak flow (mL/s) | 68.7 (27.6) | 66.9 (26.6) | 63.6 (27.9) | 69.7 (28.5) | 72.8 (26.3) |
| Duration (s) | 1.97 (0.73) | 1.77 (0.78) | 1.92 (0.62) | 1.99 (0.75) | 2.09 (0.75) |
| IPI (s) | 22.0 (79.1) | 21.3 (11.7) | 11.8 (6.7) | 21.9 (32.8) | 30.5 (11.0) |
| Time of peak flow (s) | 0.87 (0.43) | 0.7 (0.45) | 0.8 (0.34) | 0.9 (0.46) | 1.0 (0.42) |
Characteristics of the participants_
| Characteristics | Average | Beijing | Shanghai | Guangzhou | Shenzhen | |
|---|---|---|---|---|---|---|
| Gender | Male | 90.6% | 92.7% | 84.6% | 87.9% | 96.8% |
| Gender | Female | 9.4% | 7.3% | 5.4% | 12.1% | 3.2% |
| Age | Years | 31 | 32 | 33 | 35 | 26 |
| Education/degree | Doctoral | 0.2% | 1.2% | 0.0% | 0.0% | 0.0% |
| Master | 1.2% | 6.1% | 0.8% | 0.0% | 0.0% | |
| Bachelor | 45.2% | 67.1% | 61.8% | 45.6% | 20.4% | |
| Associate degree | 36.0% | 15.9% | 29.3% | 38.3% | 49.7% | |
| High school | 16.8% | 9.8% | 8.1% | 14.8% | 29.3% | |
| Other | 0.6% | 15.9% | 29.3% | 38.3% | 49.7% | |