Analysis of PM2.5 Exposure Before and After Emergency Alerts at Evacuation Sites During the 2025 Gyeongbuk Wildfire

This study analyzed the changes in PM2.5 exposure at evacuation sites announced via disaster alert messages, focusing on the 2025 wildfire case that originated in Uiseong, Gyeongsangbuk-do. For analysis, PM2.5 exposure at sites from 140 evacuation-related disaster alerts sent across five municipalities were evaluated. Hourly PM2.5 distributions were estimated from 10 h before to 48 h after the alerts were issued using observational data of PM2.5, and the inverse distance weighted (IDW) interpolation technique. The air quality index (AQI) analysis revealed several observations at “very unhealthy” and “hazardous” levels across all regions and time periods. The V-shaped re-escalation pattern accounted for the largest proportion, with 78 cases (55.71%), a mean 48-h cumulative exposure of 5,410.2 μg/m3 and 93.9% of the cases below the “very unhealthy” level at issuance re-entered high-risk levels. These results suggest that wildfire smoke exposure is insufficiently considered in evacuation site selection, and that smoke levels at the time of alert issuance alone cannot adequately reflect prior high-risk exposure or subsequent re-escalation.