A comparison of the electrical characteristics, liquid composition, and toxicant emissions of JUUL USA and JUUL UK e-cigarettes

Abstract

In 2018, JUUL entered the UK market, where EU regulations limit liquid nicotine concentration to 20 mg/mL, approximately one-third the level of JUUL products sold in the USA. We hypothesized that JUUL’s UK product was engineered to deliver greater electrical power and boost liquid vaporization such that the net nicotine delivery rate was similar to the US version. We compared electrical characteristics, liquid composition, and aerosol emissions of JUUL devices procured in the USA and the UK. Study outcomes included electrical power, total and freebase nicotine, propylene glycol/vegetable glycerin ratio, carbonyls, and reactive oxygen species. Liquids and aerosols were analyzed by GCMS, HPLC, and fluorescence. Compared to the US version, JUUL UK had approximately one-third the liquid nicotine concentration in the liquid (5.4 vs. 1.6 wt.%) and aerosol (4.7 and 1.3 wt.%). Other than nicotine concentration and yield, we found no differences in any other study outcome, including electrical power. Currently, JUUL UK emits nicotine at a far lower rate than the US product, offering an opportunity to study how this factor impacts user behavior, JUUL uptake, and other population-level outcomes across the two markets.

Nicotine delivery and user reactions to Juul EU (20 mg/ml) compared with Juul US (59 mg/ml), cigarettes and other e-cigarette products

“…For this reason, Juul marketed in Europe ('Juul EU') uses nicotine concentration of maximum 20 mg/ml. This version delivers only about a third of nicotine into aerosol compared with Juul US (Talih et al 2020). Delivery to users, however, is not known.…”

The need to more effectively regulate END markets: A primary public health lesson of the U.S. vaping associated lung injury outbreak

“…Skepticism of the public health benefit of END products in the United States is clearly high, but not without cause. Juul products in the United States contain three times the liquid nicotine concentration than the same Juul product sold in Europe [16] and END manufacturers in the United States continue to develop and aggressively market stealth vaping delivery devices, resembling USB sticks, pens, asthma inhalers, and even car fobs that can be hidden in hoodies and backpacks [17,18]. These are not practices that companies selling other smoking cessation devices follow.…”

Effects of Manufacturing Variation in Electronic Cigarette Coil Resistance and Initial Pod Mass on Coil Lifetime and Aerosol Generation

“…This suggests that some ENDS PCU may employ algorithms to overcome variation in coil resistance or actively control the power. Such algorithms could use a closed-loop control system which dynamically measures coil resistance and adjusts the power supplied to the coil in real time in order to keep the heating energy within a limit, as has been previously disclosed in the patent literature [ 36 , 37 ], and research literature [ 38 , 39 ]. Thus, the temperature of the coil and heating chamber could be controlled in a cycle to keep aerosol emission steady.…”