Wildland fire smoke exposure disparities by wildland urban interface category and land ownership

Abstract

Wildland fire activity has increased across many regions of the United States, raising concerns about smoke exposure and the health impacts of fine particulate matter (PM_2.5). Former studies on environmental disparities show smoke impacts vary across communities and regions, but most studies focus on non-spatial factors (e.g., income, race/ethnicity), potentially overlooking the spatial dimension of smoke exposure disparities. We advance this literature by assessing a location’s resilience with spatial aspects of wildland fire smoke exposure for two spatial variables: wildland urban interface (WUI) category and land ownership. We have four research objectives: 1) to identify areas with higher exposure to wildland fire PM_2.5, 2) to identify areas with greater demographic or socioeconomic vulnerability, 3) to calculate increases in unhealthy air quality days, and 4) to measure the size of the population with high smoke exposure and high vulnerability. We found Native American reservations experience 0.15–0.32 μg/m³ higher average daily PM_2.5 from wildland fire smoke, along with lower adaptive capacity, higher sensitivity, and higher vulnerability than other land ownership areas. WUI areas also showed at least 60 % higher increase in moderate air quality days (12–35 µg/m³) and greater sensitivity than non-WUI areas. Most importantly, higher vulnerability areas, defined by the lowest adaptive capacity (≥95th percentile), highest sensitivity (≥95th percentile), and highest overall vulnerability (≥95th percentile), had a higher increase in the number of moderate (12–35 µg/m³) and unhealthy air quality days (>35 µg/m³) compared to their counterparts. These findings provide insights for community-led decision-making, resource allocation, fire management strategies, and public health interventions.