Impact of Vaping Regimens on Electronic Cigarette Efficiency

Abstract

Most recent studies on electronic cigarettes (e-cigs) have been carried out using vaping regimens consistent with mouth-to-lung inhalation (MTL) and not with direct-to-lung (DTL) inhalation. This paper aimed to characterizing the influence of inhalation properties (puff duration, puff volume, airflow rate) on the mass of vaporized e-liquid (MVE). Because the literature on DTL is non-existent, an intense vaping regimen consistent with DTL inhalation (i.e., puff volume = 500 mL) was defined. The use of a low or standard (ISO/DIS 20768) regimen and the proposed intense vaping regimen were first compared using the Cubis 1 Ω atomizer on a large power range, and then by using two atomizers below 1 Ω and two others above 1 Ω on their respective power ranges. An analysis of the e-cig efficiency on the e-liquid vaporization was proposed and calculated for each MVE. The intense vaping regimen allowed a broader power range in optimal heating conditions. MVE linearly increased with the supplied power, up to over-heating conditions at higher powers. Moreover, the e-cigs’ efficiencies were higher when low-resistance atomizers were tested at high powers. All these results highlighted that the generated vapor might be better evacuated when an intense vaping regimen is used, and illustrate the obvious need to define a suitable standardized vaping regimen consistent with DTL inhalation.

Method for Quantifying Variation in the Resistance of Electronic Cigarette Coils

“…The desire for high-power ENDS pushes designers to increasingly use coils with low resistance values, which led to the introduction of the sub-ohm devices which use coils that have a resistance of < 1 (Ω) [ 16 , 17 ]. Reducing the coil resistance to 0.068 (Ω) permits instantaneous power as high as 200 W. The sub-ohm devices are reported to satisfy several features desired by users such as intense flavor, warm vape and big clouds, which is associated with high airflow that is suitable for the direct-to-lung inhale style [ 18 , 19 ]. Sub-ohm coils are mostly available in the box-mod ENDS style; however, some pod-style ENDS started to use coils with resistances of less than 1 (Ω) such as SMOK2 pod (0.8 (Ω) and NORD2 (0.3, 0.4, 0.6 (Ω)) [ 20 ], TARGET PM80 (0.2, 0.3, 0.6, 0.8 (Ω) [ 21 ], and Z-BIIP (0.48 (Ω)) [ 22 ].…”

Modeling aerial transmission of pathogens (including the SARS-CoV-2 virus) through aerosol emissions from e-cigarettes

“…While some smokers inhale without a mouth hold as in DTL style, this does not seem to involve in them a significantly higher tidal volume, most likely because it can be too irritant Higenbottam et al (1980); Tobin et al (1982a). The lesser irritant nature of ECA is a plausible explanation for a larger proportion of vapers that can tolerate DTL topography, which means suction of a much larger aerosol mass Soulet et al (2019); Cahours and Prasad (2018) and thus significantly larger puffing and tidal volumes than in MTL style (made easier by usage of high powered devices). A puff volume of 500 mL can yield under idealized laboratory conditions an inhalation tidal volume close to 3 LT Vas et al (2015), which justifies the more plausible values listed in Table 1.…”

“…For low intensity MTL vaping we assume a tidal volume of V T = 750 cm 3 supported by inference from data discussed in previous sections, while for droplet volume concentration we assume C d = 3 × 10 −3 mL/m 3 , a plausible value denoting emissions slightly above rest breathing but below normal speech in (12), fitting the 'whispered counting' data of [84]. For the number of breaths we can take the average values of 160 daily puffs in a 16 hour journey [16,62] and breathing frequency of f (br) = 16/min (in the range [12][13][14][15][16][17][18][19][20], so that N (tot) = 960 breaths/h and N (vp) = 10 breaths/h.…”

“…Vaping is characterized by a wide range of distinct and individualized usage patterns loosely described by the parameters of puffing topography : puff and inter puff duration, puff volume and flow (see Dautzenberg and Bricard (2015); Farsalinos et al (2018); Spindle et al (2017); Soulet et al (2019)). This style diversity complicates the study and evaluation of e–cigarette aerosol (ECA) emissions, more so given the need to upgrade standardization of vaping protocols, specially for the appropriate configuration of vaping machines used for research and regulation.…”

Method for Quantifying Variation in Resistance of Electronic Cigarette Coils

“…The desire for high power ENDS pushes designers to increasingly use coils with low resistance values which led to the introduction of the sub-ohm devices which use coils that have resistance of < 1  [16,17]. Reducing the coil resistance to 0.068  permits instantaneous power as high as 200 W. The sub-ohm devices are reported to satisfy several features desired by users such as intense flavor, warm vape and big clouds which is associated with high airflow that is suitable for direct to lung inhale style [18,19]. Sub-ohm coils are mostly available in the box-mod ENDS style; however, some pod style ENDS started to use coils with resistances of less than 1 [] such as SMOK2 pod (0.8 []) and NORD2 (0.3, 0.4, 0.6 []) [20], TARGET PM80 (0.2, 0.3, 0.6, 0.8 ) [21], and Z-BIIP (0.48 []) [22].…”