Abstract
BACKGROUND AND AIMS: Eleven US states and the District of Columbia have legalized the non-medical use of marijuana. Public marijuana smoking is generally prohibited, although some states have considered exemptions. This study assessed attitudes about public marijuana smoking, perceptions of harm from marijuana second-hand smoke (SHS) and self-reported marijuana SHS exposure. DESIGN: Internet panel survey fielded in June-July 2018. SETTING: United States. PARTICIPANTS: US adults aged ≥ 18 years (n = 4088). MEASUREMENTS: Current (past-30 day) tobacco product use, current marijuana use, opinions about public indoor marijuana smoking, perceptions of harm from marijuana SHS and self-reported past-7 day exposure to marijuana SHS in public indoor or outdoor areas were assessed. Weighted prevalence estimates were computed and correlates were assessed using logistic and multinomial regression. FINDINGS: Overall, 27.4% [95% confidence interval (CI) = 25.7, 29.1] of adults reported past-week marijuana SHS exposure in indoor and/or outdoor public areas; younger adults, blacks, Hispanics, those in the Northeast or West, and current marijuana and/or tobacco users were more commonly exposed (Ps < 0.0001). More than half of adults (52.4%; 95% CI = 50.7, 54.2) regarded marijuana SHS as harmful, and most (81.0%; 95% CI = 79.5, 82.4) opposed public marijuana smoking. Correlates of favoring public marijuana smoking included being male, younger (Ps < 0.01), black or Hispanic, past-month tobacco and/or marijuana users and perceiving no/low harm from marijuana SHS (Ps < 0.0001). CONCLUSION: While one in four US adults report recent marijuana second-hand smoke exposure, a majority believe marijuana second-hand smoke is harmful and most oppose public marijuana smoking.