Evaluating E-Cigarette Nicotine Form, Concentration, and Flavors Among Youth

Inclusion Criteria: * A current exclusive e-cigarette user (\>= 1 vaping bout per day) for at least the past 3 months (confirmed in lab by salivary cotinine) * 21-25 years old * Willing to abstain from all tobacco and nicotine for at least 12 hours prior to lab sessions * Willing to complete five, 6 hour lab visits * Able to read and speak English * Willing to provide informed consent Exclusion Criteria: * Self-reported diagnosis of lung disease including asthma, cystic fibrosis, or chronic obstructive pulmonary disease * Unstable or significant psychiatric conditions (past and stable conditions will be allowed) * History of cardiac event or distress within the past 3 months * Currently pregnant (determined using urine pregnancy test), planning to become pregnant, or breastfeeding * Use of other tobacco products \> 5 days in the past month * Current marijuana use \> 5 times per month * Currently engaging in a vaping cessation attempt * Ohio State University (OSU) verifies study project 2 current membership/past participation