Corrigendum to

Upon original publication, this article contained a typographical error, which could lead to confusion in the results related to the number of diacetyl/acteylpropionyl samples and thus which might affect the academic accuracy of published information. During the compilation of the Figure, internal review led to a change in the total number of investigated sweet samples. These changes to the abstract, results, and discussion sections have since been corrected. The changes are as follows: In the Abstract, “Moreover, also the number of e-liquids, containing high-risk VOCs (10% in 2016 vs. none of the samples in 2017–2018), caffeine (16% in 2017 vs. 5% in 2018), and diacetyl and acetylpropionyl (55% in 2017 vs. 27% in 2018 of sweet-flavored samples) diminished over time” became “Moreover, also the number of e-liquids, containing high-risk VOCs (10% in 2016 vs. none of the samples in 2017–2018), caffeine (16% in 2017 vs. 5% in 2018), and diacetyl and acetylpropionyl (50% in 2017 vs. 27% in 2018 of sweet-flavored samples) diminished over time.” In the Results section under the subheading Harmful ingredients: Diacetyl and Acetylpropionyl, “The amount of diacetyl and acetylpropionyl, putatively present in 56 sweet-flavored e-liquids (2016–2018), was assessed by HS-GC-MS” became “The amount of diacetyl and acetylpropionyl, putatively present in 40 sweet-flavored e-liquids (2016–2018), was assessed by HS-GC-MS.” In the Discussion section, “Compared to our study, we found that in 2017, nine samples out of the 26 sweet-flavored e-liquids (25%) were either positive for DA, AP or both, while in 2018 this was the case for 6 out of 30 sweet-flavored samples (20%)” became “Compared to our study, we found that in 2017, nine samples out of the 18 sweet-flavored e-liquids (50%) were either positive for DA, AP or both, while in 2018 this was the case for six out of 22 sweetflavored samples (27%)”.