Co-exposure to planned power outages and wildfire PM2.5 and acute healthcare utilization in California: A time-stratified case-crossover study
10 affiliations
- 1Department of Epidemiology, University of Washington School of Public Health, Seattle, Washington, United States of America
- 2Scripps Institution of Oceanography, University of California, San Diego, California, United States of America
- 3Department of Population Health Sciences, University of Utah, Salt Lake City, Utah, United States of America
- 4Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah, United States of America
- 5Physicians, Scientists and Engineers for Healthy Energy, Oakland, California, United States of America
- 6Department of Environmental Health Sciences, Columbia University Mailman School of Public Health, New York, New York, United States of America
- 7Department of Environmental and Occupational Health Sciences, University of Washington School of Public Health, Seattle, Washington, United States of America
- 8Department of Medicine, University of Washington, Seattle, Washington, United States of America
- 9Division of Research, Kaiser Permanente Northern California, Pleasanton, California, United States of America
- 10Irset Institut de Recherche en Santé, Environnement et Travail, UMR-S 1085, Inserm, University of Rennes, EHESP, Rennes, France
Abstract
Background: To prevent wildfires, electric utilities may preemptively de-energize power lines (public safety power shutoffs [PSPS]). These PSPS events may unintentionally harm health, particularly for those with pre-existing conditions like chronic obstructive pulmonary disease (COPD) or who rely on electricity-dependent medical equipment. Health impacts may worsen further if a wildfire occurs despite the power shutoff. To assess the effect of PSPS events, wildfire fine particulate matter (PM2.5) exposure, and their co-occurrence on cause-specific healthcare utilization.
Methods and findings: We identified PSPS events in California from 2013 to 2019, categorizing magnitude based on number of people without power by zip code. We leveraged zip code-level average daily wildfire PM2.5 estimates and respiratory, COPD-specific, cardiovascular, and psychiatric emergency department visits and unscheduled hospital admissions among adults aged 20+ from the California Department of Health Care Access and Information. Using a time-stratified case-crossover design, we estimated the impact of same-day and lagged PSPS events alone, wildfire PM2.5 alone, and their co-occurrence on healthcare utilization, adjusting for daily temperature.
Severe PSPS events were associated with elevated odds of same-day respiratory encounters (OR = 1.06, 95% CI: 1.02, 1.11) and lag0–3 effects were similar. These associations were stronger for COPD. Compared to no PSPS or wildfire exposure, joint PSPS and 10 μg/m3 higher wildfire PM2.5 was associated with higher odds of respiratory encounters (1.16 [95% CI: 1.10, 1.22]), with evidence of multiplicative interaction. Associations were null for cardiovascular and psychiatric encounters.
Limitations include exposure misclassification, because we assigned exposure at the residential zip code level, aggregating circuit-level data and not accounting for individual behavior or the potential for PSPS events to impact wildfire PM2.5 exposure.
Conclusions: PSPS events may increase risk of respiratory events requiring acute care utilization, especially when they co-occur with wildfire PM2.5.
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BibTeX
@article{wilner2026coexposure,
title = {{Co-exposure to planned power outages and wildfire PM2.5 and acute healthcare utilization in California: A time-stratified case-crossover study}},
author = {Lauren Blair Wilner and Caitlin G. Jones-Ngo and Chen Chen and Bethany Kwoka and Vivian Do and Joel D. Kaufman and Laura C. Myers and Tarik Benmahrnia and Joan A. Casey},
journal = {PLOS Medicine},
year = {2026},
month = oct,
doi = {10.1371/journal.pmed.1005270},
url = {https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1005270},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Co-exposure to planned power outages and wildfire PM2.5 and acute healthcare utilization in California: A time-stratified case-crossover study
AU - Lauren Blair Wilner
AU - Caitlin G. Jones-Ngo
AU - Chen Chen
AU - Bethany Kwoka
AU - Vivian Do
AU - Joel D. Kaufman
AU - Laura C. Myers
AU - Tarik Benmahrnia
AU - Joan A. Casey
PY - 2026
DA - 2026/10/27
JO - PLOS Medicine
DO - 10.1371/journal.pmed.1005270
UR - https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1005270
AB - Background: To prevent wildfires, electric utilities may preemptively de-energize power lines (public safety power shutoffs [PSPS]). These PSPS events may unintentionally harm health, particularly for those with pre-existing conditions like chronic obstructive pulmonary disease (COPD) or who rely on electricity-dependent medical equipment. Health impacts may worsen further if a wildfire occurs despite the power shutoff. To assess the effect of PSPS events, wildfire fine particulate matter (PM2.5) exposure, and their co-occurrence on cause-specific healthcare utilization. Methods and findings: We identified PSPS events in California from 2013 to 2019, categorizing magnitude based on number of people without power by zip code. We leveraged zip code-level average daily wildfire PM2.5 estimates and respiratory, COPD-specific, cardiovascular, and psychiatric emergency department visits and unscheduled hospital admissions among adults aged 20+ from the California Department of Health Care Access and Information. Using a time-stratified case-crossover design, we estimated the impact of same-day and lagged PSPS events alone, wildfire PM2.5 alone, and their co-occurrence on healthcare utilization, adjusting for daily temperature. Severe PSPS events were associated with elevated odds of same-day respiratory encounters (OR = 1.06, 95% CI: 1.02, 1.11) and lag0–3 effects were similar. These associations were stronger for COPD. Compared to no PSPS or wildfire exposure, joint PSPS and 10 μg/m3 higher wildfire PM2.5 was associated with higher odds of respiratory encounters (1.16 [95% CI: 1.10, 1.22]), with evidence of multiplicative interaction. Associations were null for cardiovascular and psychiatric encounters. Limitations include exposure misclassification, because we assigned exposure at the residential zip code level, aggregating circuit-level data and not accounting for individual behavior or the potential for PSPS events to impact wildfire PM2.5 exposure. Conclusions: PSPS events may increase risk of respiratory events requiring acute care utilization, especially when they co-occur with wildfire PM2.5.
SN - 1549-1676
SN - 1549-1277
ER -