Fig 1.
Multi-path relationship between product characteristics, use behavior and emissions.
This figure illustrates the premise that characteristics of electronic cigarette designs, e-cig operating conditions (such as power), e-liquid constituents, and user topography behavior (puff flow rate, duration, and volume) jointly impact emissions.
Table 1.
Literature e-cig emissions summarizing product characteristics and puff topography studied.
Puff flow rate (qpuff), puff volume (Vpuff), puff duration (dpuff), e-cig operating power and/or voltage (W), e-cig design characteristics (device) and e-liquid constituents (e-liquid). Shown are the variables tested and the outcome measures used to report emissions. Blank cells indicate that the variable or outcome was not reported.
Table 2.
E-cig products, E-liquids, and power settings tested.
Fig 2.
Comparison between the coil/wick designs for the two clearomizer tanks tested in this study.
Shown are photographs and CAD renderings created by RIT engineers illustrating the differences in clearomizer designs for Innokin iClear X.I dual coil tank (left two panels) and the Innokin iClear 30 dual coil tank (right two panels). The hypothesis tested in this study is that the bottom coil Innokin iClear X.I with gravity-fed wicks would produce aerosol more effectively (e.g. with higher whole aerosol mass concentrations) than the Innokin iClear 30 upper coil tank with capillary-action-fed wicks.
Table 3.
These are the command topography parameters programmed into the PES-1 system for each e-cig device. Since the device under test impacts the actual flow conditions seen by the device, the actual puff flow rate, duration, puff volume and cumulative case volumes were measured in a closed-loop feedback system. The results and subsequent analyses rely on the actual (measured) rather than the programmed (command) parameters. Each of these 10 cases was repeated for 6 trials for each e-cig product, e-liquid and power setting combinations listed in Table 2.
Fig 3.
PES-1 System validation plots used to assess the impact of the device under test and the performance of the emission system and verify conservation of mass.
Shown are two plots used to validate the PES-1 system for mean measured cumulative volume as a function of mean measured flow rate across six repeated trials at each flow condition for the five e-cigs under test (left), and conservation of mass for various e-liquids (right). The left plot shows that the actual measured volume differed from the nominal machine volume setting for every case. Actual measured volumes and measured flow rates were used in the analysis. The right plot was generated using an NJOY Vape Pen filled with AVAIL Arctic Blast (AB), Tobacco Row (TR), and Mardi Gras (MG) e-liquids across six repeated trials and ten flow conditions. Error bars are the 95% confidence intervals on the mean. Mass conservation was assessed for each product case tested.
Fig 4.
Impact of flow conditions and power setting on total particulate mass concentration of whole aerosol emissions.
The Innokin iTaste MVP 2.0 vaporizer with Innokin iClear 30 dual coil tank clearomizer generated aerosols with substantially higher total particulate mass concentrations at lower flow rates, and the flow rate effect was highly dependent on power setting. A correlation equation describing total particulate mass concentration as a function of flow rate and power setting is presented in the text and illustrated as the dashed lines in the figure. Error bars are the 95% confidence intervals on the mean.
Fig 5.
Impact of flow conditions and coil and wick design on total particulate mass concentration of whole aerosol emissions.
The Innokin iTaste MVP 2.0 vaporizer with Innokin iClear 30 top coil capillary-fed tank (i30) and Innokin iClear X.I bottom coil gravity-fed tank (iX.I) generated aerosols with higher total particulate mass concentrations at lower puff flow rates and exhibited a dependence upon coil and wick design. Error bars are the 95% confidence intervals on the mean.
Fig 6.
Impact of flow conditions for different e-liquid flavor formulations on total particulate mass concentration of whole aerosol emissions.
Shown are emission results for the NJOY Vape Pen filled with three different liquids; AVAIL Arctic Blast (AB), Tobacco Row (TR), and Mardi Gras (MG). Puff flow rate was found to impact the production of aerosol for the three flavors tested and the range of flow rates tested. For all flow rates, the total particulate mass concentration was the highest for MG, followed by AB and then TR. Error bars are the 95% confidence intervals on the mean.
Fig 7.
Impact of flow conditions on total particulate mass concentration of whole aerosol emissions across multiple device generations.
Flow conditions had a significant impact on total particulate mass concentration for all e-cig generations and styles tested. Shown here are blu Magnificent Menthol Disposable (BLU), NJOY Vape Pen (NJOY), Innokin iTaste MVP 2.0 with Innokin iClear 30 (i30) and Innokin iClear X.I (iX.I), and JUUL (JUUL). Flow rate dependence was more evident for 2nd/3rd generation devices (i30, iX.I, NJOY), which have larger tank reservoirs, compared to 1st generation cig-a-likes (BLU) and pod styles (JUUL), which have smaller capacity tanks and exhibited less enhanced aerosol production at lower flow rates. Error bars are the 95% confidence intervals on the mean.