Effects Among Smokers Who Use and Do Not Use E-Cigarettes

Inclusion Criteria: * \> 21 years of age * Smoked cigarettes on \> 25 of past 30 days * Smoked \> 5 cigarettes per day on days smoked * Smoked cigarettes \> 6 months * Carbon monoxide \> 5 PPM at baseline * Hispanic/Latino or African American/Black * Fluent in English or Spanish * Willing to switch from smoking cigarettes to ECs for 6 weeks * Regular access to telephone * Transportation to attend appointments (KC Only) Exclusion Criteria: * Primary use of other tobacco products or equal use of cigarettes and other tobacco products * Electronic cigarette use on \> 4 of the past 30 days * Currently in a smoking cessation program or another clinical trial * Use of nicotine replacement therapy or medication which aids smoking cessation in the past 30 days * Hospitalization for a psychiatric issue in the past 30 days * Heart-related event in the past 30 days. Examples include heart attack, stroke, severe angina (i.e. chest pain), ischemic heart disease, and vascular disease * Uncontrolled blood pressure at baseline * Planning to move out of San Diego or Kansas City in the next 6 weeks * Another person in the household enrolled in the study * Women: pregnant, breastfeeding, or planning to become pregnant in the next six months * Unstable mental status or health status