LINKING DAY-TO-DAY VARIABILITY IN AIR POLLUTION EXPOSURE TO HUMAN BRAIN STRUCTURE

Understanding how everyday environmental exposures affect the human brain and well-being is increasingly important in the context of global urbanization and climate change. Air pollution has been linked to adverse brain health outcomes, yet most studies focus on long-term or early-life exposure, neglecting day-to-day variability and its potential short-term effects on brain structure.
Here, we focus on how daily fluctuations in air pollution are associated with changes in structural brain integrity over time. Participants completed up to 25 testing sessions over approximately four months, each including MRI acquisition and 24-h particulate matter (PM2.5) measurements before scanning.
The current sample comprises 21 participants (mean age = 28.3 ± 5.6 years; 47.6% assigned female at birth), who completed an average of 24.1 sessions (SD = 4.1). Median 24-h PM2.5 exposure was 7.9 µg/m³ (IQR = 5.2–13.9), with a mean of 15.5 µg/m³ (SD = 30.3; range = 1.6–392.7). Preliminary analyses indicated substantial within-person variability in 24-h PM2.5 exposure across sessions (median within-person variance S² = 29.4 (µg/m³)²; SD = 5.4 µg/m³), with 68.1% of total variability reflecting session-to-session fluctuations within individuals rather than between-person differences.
We will use continuous-time dynamic modeling to examine how short-term air pollution exposure relates to temporal fluctuations in structural brain integrity. Latent factors of structural brain integrity are derived from voxel-based morphometry, mean diffusivity, and magnetization transfer saturation. This ongoing analysis will enable a novel investigation into how temporal brain dynamics are associated with real-world environmental exposures.