One in four US adults reported recent marijuana secondhand smoke exposure, but 81% opposed public marijuana smoking

Among 4,088 US adults surveyed in 2018, 27.4% reported marijuana secondhand smoke (SHS) exposure in the past week in indoor and/or outdoor public areas. Those more commonly exposed included younger adults, Black and Hispanic individuals, those in Northeast/West regions, and current marijuana or tobacco users. A majority (52.4%) perceived marijuana SHS as harmful, and 81% opposed public marijuana smoking. Male sex, younger age, minority race/ethnicity, current substance use, and perceiving low harm from SHS correlated with favoring public marijuana smoking.

Internet panel survey of 4,088 US adults (June-July 2018) assessing tobacco use, marijuana use, opinions on public indoor marijuana smoking, perceived harm from marijuana SHS, and self-reported past-7-day SHS exposure. Weighted prevalence estimates with logistic and multinomial regression.

As states legalize cannabis, public smoking policies are being debated. This provides baseline data showing substantial public exposure despite general opposition, informing smoke-free policy design.

The disconnect between 27.4% exposure and 81% opposition suggests enforcement of existing public smoking bans is inadequate. As cannabis becomes more legal, extending clean air policies to include marijuana smoke becomes increasingly important.

Internet panel (may not represent all US adults); self-reported exposure (no biomarker validation); cross-sectional; cannot distinguish marijuana smoke from other sources; perception of harm does not equal actual harm; 2018 data predates more recent legalization.