Cannabis secondhand smoke exposure in apartments is as common as tobacco secondhand smoke | Research

The takeaway

A population survey in Ontario found 7.5% of multi-unit housing residents reported involuntary exposure to cannabis smoke from neighbors, similar to the 6.6% reporting tobacco smoke exposure, with lower-income residents disproportionately affected.

Housing policy makers, public health officials, landlords, and multi-unit housing residents.

7.5% exposed to cannabis smoke

What the researchers found

Among multi-unit housing residents in Ontario, 7.5% reported environmental cannabis smoke (ECS) exposure and 6.6% reported environmental tobacco smoke (ETS) exposure from neighboring units. ECS exposure was associated with being single, lower household income, and past-year cannabis use. Cannabis smoke exposure prevalence was comparable to tobacco smoke.

Why it matters

As cannabis legalization expands, involuntary exposure to cannabis smoke in multi-unit housing is an emerging public health concern. This is the first study to measure its prevalence alongside tobacco smoke exposure.

The numbers in context

Environmental cannabis smoke: 7.5% (95% CI 5.4-10.4%). Environmental tobacco smoke: 6.6% (95% CI 4.5-9.5%). Exposed individuals more likely to be single, have lower income, and have used cannabis.

How the study worked

Population random-digit-dial survey from the 2017 Centre for Addiction and Mental Health Monitor for Ontario, Canada. Self-reported cannabis and tobacco smoke entering the home from neighboring units at least once in the past 6 months.

What this study cannot tell us

Self-reported exposure with potential recall bias. Ontario-specific, pre-full Canadian legalization (October 2018). Cannot distinguish between smoke from the building interior versus exterior. No objective measurement of smoke levels.

How to read the evidence

Rated moderate because this is a population-representative RDD survey, though self-report and a single province limit the findings.

When this study was published

Published in 2019 using 2017 data, before full Canadian recreational legalization.

The bigger picture

Multi-unit housing residents are disproportionately lower-income and include vulnerable populations (children, elderly, people with respiratory conditions). Involuntary cannabis smoke exposure adds a new dimension to housing health policy that legalization frameworks have largely not addressed.

Questions still open

Should multi-unit housing cannabis smoking bans mirror tobacco smoking bans? Does secondhand cannabis smoke carry similar health risks to tobacco? How should landlords and policymakers address this issue?

Common questions

Is secondhand cannabis smoke in apartments a real problem?

This study found it is about as common as secondhand tobacco smoke, affecting 7.5% of multi-unit housing residents in Ontario.

Who is most affected?

Lower-income residents are disproportionately exposed, as they are more likely to live in multi-unit housing with shared ventilation and less ability to choose their living conditions.

Read the original research

Prevalence of Involuntary Environmental Cannabis and Tobacco Smoke Exposure in Multi-Unit Housing.

International journal of environmental research and public health, 16(18)

View on PubMed ↗Publisher’s paper ↗

Citation

Chu, Alanna K; Kaufman, Pamela; Chaiton, Michael. (2019). Prevalence of Involuntary Environmental Cannabis and Tobacco Smoke Exposure in Multi-Unit Housing.. International journal of environmental research and public health, 16(18). https://doi.org/10.3390/ijerph16183332