Figure 3
From: High concentrations of flavor chemicals are present in electronic cigarette refill fluids
Frequency Distribution, Chemical Classes, and Hazard Classification of the Flavor Chemicals. (a) The frequency with which individual flavor chemicals were found in at least 21 products. The x-axis is the number of refill fluids in which the chemicals were found and the y-axis is sorted according to decreasing frequency of their occurrence. Frequency ranged from 21–164 with the highest being ethyl maltol. Chemicals appearing less frequently are shown in Supplemental Fig. 1. (b) The chemical classes of the flavor chemicals (x-axis) are plotted versus the frequency of occurrence of each class of flavor chemicals (y-axis). (c) The classification of flavor chemicals into color coded hazard categories using the European safety data (x-axis) are plotted versus the frequency of occurrence of flavor chemicals in each hazard category (y-axis).
