Abstract
Use of both cannabis and tobacco has surpassed use of tobacco alone among young adults in California. To better understand why, we collected data with 32 young adults ages 18-30 in Northern California who regularly used cigarettes and cannabis and had diverse sexual, gender, racial, and ethnic identities. Geographically-explicit ecological momentary assessment (EMA; 30 days) was integrated with qualitative mapping interviews. We found contrasting situations of use for cannabis (e.g., around other people) versus cigarettes (e.g., recent discrimination) and different reasons for why participants chose one substance over the other (e.g., enhancing experiences vs. stepping away). Understanding when and why diverse young adults choose cannabis versus cigarettes as they navigate everyday environments helps explain how cannabis and tobacco retail markets shape substance use disparities over time.