Table 2.

Example of Classifying E-Liquids According to Their Primary and Secondary Flavors Using the Main and Subcategories of Our Proposed Flavor Wheel Shown in Figure 2. Classification Is Based on E-Liquid Marketing Descriptions

E-liquid	Flavor description	Main category primary flavor (inner wheel)	Subcategory primary flavor (outer wheel)	Secondary flavor? (yes/no)	Subcategories secondary flavor (outer wheel)
1	Raspberry tea	Coffee/tea	Tea	Yes	Raspberry
2	Watermelon combined with kiwi and lemon	Fruit	Watermelon	Yes	Kiwi, lemon
3	Strawberry with a hint of menthol	Fruit	Strawberry	Yes	Menthol
4	Chocolate	Other sweets	Chocolate	No	–
5	Bubble gum	Candy	Bubble gum	No	–
etc.