aerosol droplet-size distribution and airborne nicotine portioning in particle and gas phases emitted by electronic cigarettes.

Introduction:
This text is a scientific report on the study of particle size distribution and nicotine delivery emitted by electronic cigarettes (ECs). The study aims to understand how nicotine is delivered as an aerosol with an appropriate aerodynamic size, which is a necessary step towards obtaining a well-designed nicotine transfer from the respiratory tract to the bloodstream, to better satisfy cravings and improve smoking cessation rates. The authors used recent models of EC devices and a dedicated vaping machine to generate aerosols under various experimental conditions, including varying the EC power level using two different types of atomizers.

Key Points:

* The study used a cascade impactor to measure the aerodynamic particle sizing of the resulting aerosol and liquid chromatography coupled with a photodiode array to quantify the nicotine concentration.
* The vaporization process and the physical and chemical properties of the EC aerosol were similar at 15 watts (W) and 25 W, but quite distinct at 50 W.
* The mass median aerodynamic diameters ranged from 1.06 to 1.19 µm for low power and from 2.33 to 2.46 µm for high power.
* The nicotine concentrations of aerosol droplets were approximately 11 mg/mL for low power and 17 mg/mL for high power.
* The aerosol droplet particle phase of the total nicotine mass emitted by EC was 60% for low power and 95% for high power.
* The study found that varying the power level and the design of atomizer, including the type of coil and the value of resistance used, affects the particle-size distribution and the airborne nicotine portioning between the particle phase and the gas phase in equilibrium with the airborne droplets.
* The study used a vaping machine that enables the generation of fully controlled emissions in association with a cascade impactor to study the influence of the specific power applied to both low-power and high-power atomizers on the physical and chemical features of the emitted aerosol.

Main Message:
The study highlights the importance of understanding the particle size distribution and nicotine delivery emitted by electronic cigarettes for their design and use in smoking cessation therapies. By varying the power level and atomizer design, the study found that it is possible to obtain a well-designed nicotine transfer from the respiratory tract to the bloodstream, which can better satisfy cravings and improve smoking cessation rates. however, the study also emphasizes the need for further research to fully characterize the relation between EC emissions and the aerodynamic diameter of the droplets and the chemical composition of the airborne particles in equilibrium with gas phases. Overall, the study provides valuable insights into the design and use of electronic cigarettes for smoking cessation therapies.

Lalo h, Leclerc L, Sorin J, Pourchez J. aerosol droplet-size distribution and airborne nicotine portioning in particle and gas phases emitted by electronic cigarettes. Scientific reports. 2020;10(1):21707. doi:10.1038/s41598-020-78749-6