Spatial clustering of air pollutant trends and exposure burden across Romania (2013-2024).

Spatial clustering analysis reveals persistent high multi-pollutant burden and increasing trends in specific regions of Romania from 2013 to 2024.

• Why it matters: Identifying regions with simultaneous multi-pollutant exposure and worsening trends is crucial for targeted air quality management and public health protection, yet such assessments have been lacking at the national scale in Romania.
• What they did: The study analyzed hourly concentrations of PM 2.5, PM 10, NO 2, and O 3 from CAMS reanalysis data validated against 317 in situ stations, using Mann-Kendall, Sen's slope, and LISA methods to detect trends and spatial clusters.
• The result: Findings show significant winter increases in PM 2.5 and PM 10 in northern Transylvania and summer O 3 increases exceeding 15 μg/m³ per decade in southeastern and western Romania, with high-high trend clusters in specific regions indicating priority areas for air quality interventions.