Wearable Personal PM_2.5 Monitoring During Wildfire Smoke Episodes in Metro Detroit

Wildfire smoke has increasingly affected air quality across North America, raising concerns about the health effects of fine particulate matter (PM_2.5) exposure, including potential impacts on brain health. However, relatively few studies have characterized personal PM_2.5 exposure during these events using wearable monitoring. We examined daily personal PM_2.5 concentrations during wildfire smoke episodes in southeast Michigan alongside neighborhood outdoor PM_2.5 estimates. Four participants (one adolescent and three adults) wore AirBeam3 personal monitors during ongoing studies. Neighborhood outdoor PM_2.5 was estimated using the average of three nearest PurpleAir outdoor air quality sensors, and wildfire smoke days were identified using state air quality advisories. Group-level descriptive statistics summarized personal and neighborhood outdoor PM_2.5 and self-reported time spent outdoors. Exploratory within-participant analyses quantified associations between neighborhood outdoor and personal PM_2.5 concentrations on smoke and non-smoke days. Neighborhood outdoor daily PM_2.5 concentrations were higher during wildfire smoke days than non-smoke days (87.6 ± 80.2 vs. 12.3 ± 7.0 μg/m³). Personal PM_2.5 concentrations were more than five times higher during wildfire smoke days (28.2 ± 20.0 vs. 5.1 ± 4.7 μg/m³) than non-smoke days. Within participants, every 10 μg/m³ increase in neighborhood PM_2.5 was associated with 2.3 μg/m³ increase in personal PM_2.5 concentrations. Wearable PM_2.5 monitoring captured elevated personal exposures while providing individual-level exposure information beyond neighborhood outdoor air quality estimates. These findings demonstrate that wearable monitoring complements neighborhood air quality measurements by capturing individual-level exposure, providing a more comprehensive assessment of real-world wildfire smoke exposure for future studies examining the effects on brain health.