Comparative Studies of Environmentally Persistent Free Radicals on Total Particulate Matter Collected from Electronic and Tobacco Cigarettes

Abstract

In the current study, electron paramagnetic resonance (EPR) spectroscopy was employed to measure environmentally persistent free radicals (EPFRs) in the total particulate matter (TPM) of mainstream and sidestream TPM of conventional cigarettes and the TPM of ecigarettes. Comparable concentrations of EPFRs were detected in both sidestream (8.05 ± 1.32) × 10 4 pmol/g and mainstream TPM (7.41 ± 0.85) × 10 4 pmol/g of conventional cigarettes. TPM exposure to air resulted in long-lived oxygen centered, secondary radicals with EPR g values of 2.0041 for mainstream and 2.0044 for sidestream. Surprisingly, despite no combustion process, the TPM from e-cigarettes (menthol flavor of NJOY and V2 brands) also contain EPFRs with g values of 2.0031−2.0033, characteristic of carbon centered radicals, while the radical signal in the vanilla flavor of V2 brand was remarkably similar to semiquinones in cigarette smoke with a higher g value (2.0063). The radical concentration in e-cigarettes was much lower as compared to tobacco TPM. Although the production of ROS generated by e-cigarettes is comparatively lower than ROS generated by conventional cigarettes, EPFRs in e-cigarettes appear to be more potent than those in tobacco TPM with respect to hydroxyl radical generation yield per unit EPFR. EPFRs in e-cigarette TPM may be a potential source of health impacts.

Environmentally persistent free radicals are ubiquitous in wildfire charcoals and remain stable for years

“…4 and Table S3). These samples showed an initial slight increase in EPFRs after the first year, possibly due to the formation of secondary radicals during oxidative aging as previously described for pyrolysis of tobacco 38 . Over the subsequent four sampling years, the EPFR concentrations decreased only slightly, with the most pronounced reduction occurring in the fifth year (Fig.…”

Electronic nicotine delivery system design and aerosol toxicants: A systematic review

“…Shein et al [89] observed similar amounts of free radicals in aerosols using standard wicking and heating, a mesh coil, and an air control. Hasan et al [90] found free radical concentration from two closed-system ENDS were significantly lower than conventional tobacco cigarettes, but the oxidative potency from the free radicals originating from the ENDS was much higher. No clear relationship between free radicals and device design has been observed.…”

“…Group A HPLC 41 [14, 22-26, 28, 30-33, 36-38, 40, 41, 45-48, 60-65, 67, 69, 70, 74-76, 79, 80, 82-84, 97, 106, 110, 111, 114] 3 [47,50,69] GC-FID 3 [39,68,92] 2 [39,71] TD-GC-MS 2 [94,95] 4 [50,64,94,95] GC-MS 11 [29, 33, 34, 39, 41-43, 69, 81, 93, 105] 13 [39,48,49,51,59,69,76,79,83,85,93,105,114] 7 [49,59,69,76,83,85,114] EPR 8 [14,56,58,73,84,[88][89][90] ICP-MS 11 [49, 52-54, 60, 69, 78, 79, 83, 86, 114] ICP-OES 4 [51,87,112,113] SF-ICP...…”

Environmentally Persistent Free Radicals as Sources of POPs

“…Many organic molecules are EPFR precursors. These classes of organic compounds have been reported to form EPFRs: aromatics [40,43,44] chloroaromatics [2,[45][46][47][48], polycyclic aromatic hydrocarbons (PAHs) [49,50], complex organic polymers [31,51], and microplastics [52]. Another abundant source of EPFR precursors is soil, which contains a vast reservoir of metals and organics [20].…”