Identifying barriers and facilitators of harm reduction among adult dual users of e-cigarettes and cigarettes - PROJECT SUMMARY/ABSTRACT Dual use of e-cigarettes and cigarettes (i.e., dual use) is a common tobacco use pattern among adults in the United States. The most common use for e-cigarettes among dual users is for harm reduction (i.e., the complete transition to e-cigarettes or total cessation). Dual use may reduce the burden of tobacco use if it is a temporary stage, i.e., cigarette smokers using e-cigarettes to quit, transition to e-cigarette use only, or total cessation (i.e., harm reduction). However, this does not always translate in real life. A significant number of dual users still maintain dual use, and evidence is mixed as to the effectiveness of e-cigarettes as a cessation tool. Furthermore, dual users face barriers to and facilitators of harm reduction that are not clearly understood. As such, we must understand these barriers/facilitators to develop effective interventions to help dual users quit or reduce their harm. This study aims to identify these contextual and individual barriers that prevent dual users from quitting cigarettes and the daily triggers associated with cigarette smoking and identify some facilitators that may promote harm reduction. I will recruit two separate groups of adult users of e-cigarettes and cigarettes (n= 50 each; 50% women; age ≥21years) to 1) use ecological momentary assessment (EMA) in a longitudinal within-subject study design to identify daily triggers and settings of cigarettes smoking for 14 days and 2) conduct focus group discussions to explore the contextual barriers/facilitators of harm reduction. Combined, the proposed studies will give real-world evidence on the barriers that prevent adult dual users who use e-cigarettes with the intent to quit but do not quit or reduce their harm. Though I have expertise in tobacco research, I lack formal training in qualitative and EMA methodology. The mentoring team has outstanding experience in epidemiological research of tobacco product use, qualitative methods, and EMA methodology and is committed to supporting Dr. Osibogun in her training and professional development. Through this K01, Dr. Osibogun will develop the skills to achieve her long-term goal of becoming an independent researcher with expertise in tobacco research, which will position her to develop and submit a R01 intervention grant proposal that can leverage EMA and other techniques learned through the K01 training experience to improve cessation outcomes among dual users.