Linking Urban Land Use Change and Tropospheric Ozone Dynamics in a Mid-Sized City

This study develops an integrated geospatial framework to examine the spatial-temporal relationship between urban land-use change and tropospheric ozone dynamics within a mid-sized functional urban system, using Bolu, Türkiye, as a case study. Mid-sized urban systems remain underrepresented in air-quality and land-use research despite increasing environmental pressures under ongoing urbanization. The spatial framework was defined to encompass the central urban area and its surrounding peri-urban and transportation-influenced transition zones. Future land-use patterns were estimated to 2030 using the MOLUSCE model, while tropospheric ozone indicators were derived from Sentinel-5P observations for the 2020–2024 period and descriptively extended to 2030 using the Theil–Sen slope estimator. A fishnet-based spatial regionalization approach enabled consistent comparison between ozone trends and urban expansion intensity, quantified using the Urban Expansion Intensity Index (UEII). The integrated framework provides a spatially coherent basis for understanding land–atmosphere interactions in mid-sized urban systems.