Association between wildfire smoke exposure and parents' adoption of protective behaviours: Exploring the role of objective and subjective smoke exposure.

Exposure to wildfire smoke poses a significant threat, particularly to children, even at low concentrations. Although several agencies monitor and disseminate air quality data, some parents rely on sensory cues to decide on protective behaviours, such as using air purifiers. We investigated relationships between objective smoke exposure measures (from air monitoring data), parents' subjective perceptions of smoke exposure (perceived through sight or smell), and their protective behaviours during wildfire smoke events. We combined survey responses from 2086 parents in wildfire-prone regions of the western US and Canada with three and a half years of wildfire smoke data (2020-2023). Parents' subjective perceptions of being exposed to smoke were associated with objective smoke exposure measures; however, subjective exposure was more strongly related to protective behaviours than objective exposure measures. Specifically, parents who perceived being exposed to wildfire smoke took, on average, more than one additional protective action (b = 1.11, 95% CI: 0.92‒1.30), compared to those not who did not report smoke exposure. In comparison, every 10 μg/m3 increase of PM2.5 on smoke days predicted only a 0.23 increase in the number of protective actions adopted (95% CI: 0.06‒0.40). Exploratory analyses indicated non-linear relationships between objective smoke exposure and protective behaviours, with initial increases prompting more actions, plateauing at moderate levels, and rising again at higher exposure levels. As wildfire smoke can be harmful even when not visible or detectable by smell, smoke messaging should better connect objective air quality data like the Air Quality Index with parents' subjective perceptions of wildfire smoke.