Seven-year satellite assessment of NO2 hotspot persistence and relative exposure inequality in Bursa, Türkiye
Urban Climate, cilt.68, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 68
- Basım Tarihi: 2026
- Doi Numarası: 10.1016/j.uclim.2026.103080
- Dergi Adı: Urban Climate
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, INSPEC
- Anahtar Kelimeler: Air quality management, Getis-Ord Gi*, Industrial corridors, Sentinel-5P/TROPOMI, Urban air pollution
- Bursa Uludağ Üniversitesi Adresli: Evet
Özet
Nitrogen dioxide (NO2) remains a major air-quality concern in urban-industrial regions, yet long-term hotspot persistence, population co-location, and industrial-zone associations are rarely evaluated together. This study analyzed Sentinel-5P/TROPOMI tropospheric NO2 columns over Bursa, Türkiye, for 2019–2025 using QA-filtered observations and a fixed 500 m reference height to express the column field as a surface-equivalent relative NO2 indicator. The transformed product was compared with ground-based measurements at three monitoring stations and showed significant temporal agreement, with daily Pearson correlations of 0.482–0.730 and monthly correlations of 0.587–0.860. However, systematic negative bias confirmed that the product should be interpreted as a relative indicator rather than an absolute surface concentration. Long-term trends were evaluated using the Mann-Kendall test and Theil-Sen estimator, the COVID-19 effect using the Wilcoxon signed-rank test, and spatial clustering using annual Getis-Ord Gi* statistics. The NO2 indicator declined significantly in 2020, but the provincial long-term trend was not statistically significant, and the main hotspot structure remained stable. Persistent hotspots, defined as pixels classified as hotspots in at least five of seven years, were concentrated in the northern urban-industrial corridor. These areas covered only 17.36% of the study area but contained 83.55% of the provincial population, while approximately 74% of pixels within organized industrial zone buffers were persistent hotspots. Because absolute guideline compliance could not be reliably assessed, the study characterizes relative spatial exposure inequality. The findings identify priority corridors for denser monitoring and spatially targeted air-quality management.