Public health guidance about wildfire smoke: Four targets for improvement.

Many are calling to improve public health guidance to reduce the harms of increasing wildfire smoke in Canada, including authoritative guidance from public health agencies and related public-facing risk communications. Yet the meaning of "improvement" is open to interpretation. This commentary proposes four conceptually distinct targets for improving public health guidance about wildfire smoke and suggests that each invites different research methods, interdisciplinary expertise, and public involvement. First, the evidence base that informs public health guidance must be strengthened and expanded, better characterizing risk among subpopulations, longer-term health effects, and the impacts of protective interventions. Second, recommendations for action should engage with ethical questions about trade-offs and be informed by interdisciplinary collaboration and public deliberation. Third, the effectiveness of guidance-how well it informs about health risks, persuades people to adopt recommended actions, and improves health outcomes-should be evaluated with robust methods that go beyond self-reported understanding and intentions, while accounting for access to support needed for behaviour change. The fourth and final target is an overarching process and content standard for authoritative guidance. Developing and deliberating such a standard at appropriate levels within Canadian public health systems is necessary to support iterative efforts to improve wildfire smoke guidance.