Advancing the Community Health Vulnerability Index for Wildland Fire Smoke Exposure

Wildfire smoke risks are not uniformly distributed across people and places, and the most vulnerable communities are often disproportionately impacted. This study develops a Community Health Vulnerability Index (CHVI) using three major vulnerability components: adaptive capacity, sensitivity, and exposure at the national and regional level. We first calculated sensitivity and adaptive capacity sub-indices based on nine sensitivity and twenty adaptive capacity variables. These two indices were then combined with an exposure sub-index to develop CHVI. Finally, we conducted several analyses with the calculated sub-indices and CHVI to: 1) explore associations between the level of fine particulate matter less than 2.5 µm in diameter (PM2.5) originating from wildland fire (fire-PM2.5) and the sub-indices and CHVI; 2) calculate population size in high sensitivity (>95th percentile), low adaptive capacity (<5th percentile) and high vulnerability (>95th percentile) counties; and 3) count the annual number of moderate (15-35μg/m3) and unhealthy (above 35μg/m3, United States (US) Environmental Protection Agency National Ambient Air Quality Standards regulatory level) air quality days, categorized by the percentiles of the sub-indices and CHVI. This study has three main findings. First, we showed that the counties with higher daily fire-PM2.5 exposure tend to have lower adaptive capacity, higher sensitivity, and higher vulnerability. Relatedly, counties at high risk tended to experience a higher number of moderate and unhealthy air quality days per year. Second, we found that 7.4, 6.7, and 9.8 million people out of 332 million in the contiguous US reside in the lowest adaptive capacity (<5th percentile), the highest sensitivity (>95th percentile), and the highest vulnerability (>95th percentile) counties, respectively. Third, we identified that the US Northwest, Northern Rockies, and Southern regions tended to have higher vulnerability than other areas. Accurately identifying a community’s vulnerability to wildfire smoke can help individuals, researchers, and policymakers better understand, prepare for, and respond to future wildfire events.  

Impact/Purpose

This research seeks to build upon the previous vulnerability index in three respects. First, we incorporate adaptive capacity in the vulnerability assessment. While adaptive capacity is crucial for accurately reflecting the actual vulnerability of a natural system, region, or community (Rappold et al., 2017; Smit and Pilifosova, 2003), only a few studies have considered adaptive capacity. In this study, we included 20 variables related to adaptive capacity covering six demographic variables, nine socioeconomic variables, and five infrastructure variables, as described in the Methods. Second, we conduct vulnerability assessment at the regional level. The existing vulnerability assessments often rely on national-level analysis, which can overlook vulnerable areas outside of national-level high vulnerability regions. 

Citation

Jung, J., J. Wilkins, C. Schollaert, Y. Masudae, J. Flunkerd, R. Connolly, S. D&rsquo;Evelynd, E. Bonilliab, A. Rappold, R. Haugo, M. Marlierf, AND J. Spector. Advancing the Community Health Vulnerability Index for Wildland Fire Smoke Exposure. Elsevier BV, AMSTERDAM, NETHERLANDS, 906:167834, (2024). [DOI: 10.1016/j.scitotenv.2023.167834]

DOI: Advancing the Community Health Vulnerability Index for Wildland Fire Smoke Exposure