Some studies have reported emissions in terms of the HPHC mass ratio, f HPHC (mg/mg) (i.e., the mass of selected HPHCs per unit mass of TPM) ( 17, 26, 30, 31, 33). Emissions have frequently been reported as the total condensed aerosol, commonly referred to as the Total Particulate Matter (TPM) yield per puff and the Harmful and Potentially Harmful Constituents (HPHC) Yield ( 2, 3, 14– 32). To date, no standard emissions outcome measures have been agreed upon, while a wide variety of metrics have been reported. Prior work shows that emissions are a strong function of puff flow rate ( 11), and that puff flow rate and other topography behavior varies widely with individual users and devices ( 12, 13).
It remains unclear how the puffing regimes used relate to the normal range of the device permitted by the manufacturer, or how the puffing regimes correlated with user behavior. There is little consistency in puffing regimes being used for ENDS emission studies studies have used 15 ml/s, 4 s puffs ( 1), 27 ml/s, 3 s puffs ( 49), 39 ml/s, 1.8 s puffs ( 2), 27.5 ml/s, 2 s puffs ( 3, 4), 17.5 ml/s 2 s puffs ( 5– 7), 10 ml/s, 4 s puffs ( 8), and in some articles the puffing protocol is unclear ( 9, 10). The variation in operating envelope observed between ENDS products of differing design by various manufacturers has implications for development of standardized emissions testing protocols and data reporting required for regulatory approval of new products. Results are presented which provide preliminary estimates for the effective maximum aerosolization flow rate and duration envelope of each ENDS. The maximum aerosolization flow rate was defined to be when the onset of liquid aspiration was evident, at flow rates ranging from 50 to 88 (mL/s). The minimum aerosolization flow rate ranged from 2.5 to 23 (mL/s) and the minimum aerosolization duration ranged from 0.5 to 1.0 (s) across the ENDS studied. This study reports an accurate, unbiased method for measuring the minimum and maximum aerosolization puff flow rate and duration of seven pod-style, four pen-style and two disposable ENDS. An accurate and unbiased method for quantifying the flow condition operating envelope of ENDS is needed to quantify product characteristics across research laboratories. The minimum puff flow rate and duration at which the ENDS device begins to generate aerosol are important parameters in quantifying the viable operating envelope of the device and are essential to formulating a design of experiments for comprehensive emissions characterization. Many Electronic Nicotine Delivery Systems (ENDS) employ integrated sensors to detect user puffing behavior and activate the heating coil to initiate aerosol generation.
4Department of Mechanical and Industrial Engineering, Rochester Institute of Technology, Rochester, NY, United States.3Department of Electrical and Computer Engineering, Rochester Institute of Technology, Rochester, NY, United States.
2Department of Chemistry and Materials Science, Rochester Institute of Technology, Rochester, NY, United States.1Department of Mechanical Engineering, Rochester Institute of Technology, Rochester, NY, United States.Emma Sarles 5, Mahagani Thomas 2, Bryan T.