It protects cigarettes from bending and gives the exterior more stable surfaces for labels, health warnings, barcodes, tax marks, and branding, where branding is allowed
Ryan [26] noted numerous etiological factors contributing to lung cancer disparities, including smoking (i.e., screening age, dose, duration, cessation, menthol, genetics, and metabolism), environment (i.e., body mass index, alcohol consumption, radon, pollution, and geographic location), early detection (i.e., screening eligibility, screening uptake, and biomarkers), societal factors (stage at presentation, insurance status, belief systems, socioeconomic status, access to care, use of care, and health literacy), and biology (i.e., genetics and metabolism, transcriptomics, and biomarkers)
Aside from their affordability and similarity to smoking, there are a few other common reasons why you might want to consider picking up a disposable: For an emergency: Whatever type of e-cig you usually use, it's always a good idea to have one of these stored, say, in your car for when you really need it and you get caught short
E-liquid contains Propylene Glycol, Vegetable Glycerine, nicotine and flavouring