Reactive Oxygen Species Emissions from Supra- and Sub-Ohm Electronic Cigarettes

Introduction:
This article investigates the emissions of reactive oxygen species (ROS) from electronic cigarettes (ECIGs), specifically focusing on the effects of power, device design, and liquid composition. The study also examines ROS emissions in sub-Ohm devices, a category that has not been extensively studied.

Key Points:

* an acellular 2',7'-dichlorofluorescin (DCFh) probe technique was optimized to measure ROS in ECIG aerosols.
* ROS emissions were measured in sub-Ohm and supra-Ohm ECIGs while varying power, heater coil head design, and liquid composition (PG/VG ratio and nicotine concentration).
* Liquids were made from analytical standards of PG, VG, and nicotine and contained no flavorants.
* at high powers, ROS emissions in ECIGs and combustible cigarettes were similar.
* across device designs, ROS emissions were uncorrelated with power (R2 = 0.261) but were highly correlated with power per unit area (R2 = 0.78).
* an increase in the VG percentage in the liquid yielded higher ROS flux, and nicotine did not affect ROS emissions.
* ROS emissions are a function of device design and liquid composition at a given power.
* For a given liquid composition, power per unit area of the heating coil is a promising metric for predicting ROS emissions across device designs and operating conditions.
* ROS formation is intrinsic to ECIG operation and not solely a by-product of particular flavorants, contaminants, or additives.

Main Message:
This study highlights the significance of ROS emissions in ECIGs, which can reach levels similar to combustible cigarettes at high powers, especially in sub-Ohm devices. The findings emphasize the importance of considering power per unit area as a crucial factor in predicting ROS emissions. The research also underlines that ROS formation is inherent to ECIG operation, regardless of the presence of specific flavorants or additives, suggesting that potential health risks associated with ECIG use should be further investigated.

haddad, Christina, Rola Salman, ahmad El-hellani, Soha Talih, alan Shihadeh, and Najat aoun Saliba. “Reactive Oxygen Species Emissions from Supra- and Sub-Ohm Electronic Cigarettes.” Journal of analytical Toxicology 43, no. 1 (January 1, 2019): 45–50. https://doi.org/10.1093/jat/bky065.