E-Cigarette and Cigarette Nicotine Delivery and Abuse Liability in Cigarette Smokers and Dual Users

Inclusion Criteria: * be at least 18 years old * live within 30 miles of the research site * interested in/willing to use an e-cigarette during study visits * be willing and able to complete study procedures including specimen collection, survey completion, and remaining nicotine abstinent for 12 hours prior to each study visit * speak and understand English * willing to provide informed consent * bring usual brand cigarettes to screener study visit. Additional Inclusion criteria for smokers: * smoke at least 10 cigarettes per day for the past three months, * exhaled more than equal to 6 ppm carbon monoxide at the screener visit. Additional Inclusion criteria for dual users: * smoke more than equal to 5 tobacco cigarettes per day for the last 3 months, * use e-cigarettes at least 15 days per month for the last 3 months, and * bring e-cigarette device to screener study visit. Exclusion Criteria: * currently suffering from lung disease including asthma, cystic fibrosis (CF), or chronic obstructive pulmonary disease (COPD), unless it is well-controlled, * currently pregnant or breast-feeding or have plans to become pregnant or begin breast-feeding at any point during the study, * intoxicated at study visits (breath alcohol testing and clean urine drug screen), * any known allergies or sensitivity to the known major constituents contained in the aerosol of the study e-cigarette devices (e.g., flavorants, vegetable glycerin, propylene glycol), * User of zero-nicotine e-ciga…