BACKGROUND AND AIMS Eleven U.S. states and the District of Columbia have legalized 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 secondhand smoke (SHS), and self-reported marijuana SHS exposure. DESIGN Internet panel survey fielded in June-July 2018. SETTING USA PARTICIPANTS: U.S. adults aged ≥18 years (n=4,088). 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% 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 (p<.0001). Over 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 (p<.01), black or Hispanic, past-month tobacco and/or marijuana users, and perceiving no/low harm from marijuana SHS (p<.0001). CONCLUSION While one in four U.S. adults report recent marijuana secondhand smoke (SHS)exposure, a majority believe marijuana SHS is harmful and most oppose public marijuana smoking.

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2018 年美国成年人对公共大麻吸烟的自我报告接触、看法和态度

背景和目标 美国的 11 个州和哥伦比亚特区已将大麻的非医疗用途合法化。公共场所吸食大麻通常是被禁止的，尽管一些州已经考虑过豁免。本研究评估了公众对吸食大麻的态度、对大麻二手烟 (SHS) 危害的看法以及自我报告的大麻 SHS 暴露情况。设计互联网小组调查于 2018 年 6 月至 7 月进行。设置美国参与者：美国 18 岁以上成年人 (n=4,088)。测量当前（过去 30 天）烟草产品使用情况、当前大麻使用情况、对公共室内吸食大麻的看法、对大麻 SHS 危害的看法以及过去 7 天在公共室内或室外区域自我报告的大麻 SHS 暴露情况进行了评估. 计算加权患病率估计值，并使用逻辑和多项回归评估相关性。调查结果 总体而言，27.4% (95% CI: 25.7, 29.1) 的成年人报告过去一周在室内和/或室外公共区域接触过大麻二手烟；年轻人、黑人、西班牙裔、东北部或西部的人以及目前吸食大麻和/或烟草的人更常见（p<.0001）。超过一半的成年人 (52.4%; 95% CI: 50.7, 54.2) 认为大麻 SHS 有害，大多数人 (81.0%; 95% CI: 79.5, 82.4) 反对在公共场所吸食大麻。支持公共吸食大麻的相关因素包括男性、年轻 (p<.01)、黑人或西班牙裔、过去一个月的烟草和/或大麻使用者，以及认为大麻 SHS 没有/低危害 (p<.0001)。结论 虽然四分之一的美国