Applicability Failures of Urban Air Quality Models in Coastal Cities and the Role of Sea–Land Breeze and Boundary Layer Dynamics

Urban air quality models are widely applied in environmental assessment and policy making, yet their applicability in coastal cities remains limited. This paper examines why commonly used urban air quality models often fail to represent pollution dynamics in coastal environments. Focusing on conceptual rather than technical issues, the analysis highlights mismatches between model assumptions and key coastal atmospheric processes, including land–sea thermal contrast, sea–land breeze circulation, boundary layer stratification, and strong temporal variability. These processes challenge assumptions of spatial homogeneity, predictable mixing, and monotonic dispersion that underpin many urban models. The paper argues that temporal averaging further obscures critical transition periods that govern pollutant accumulation and exposure. By framing these limitations as applicability failures rather than model errors, the study emphasizes the need for context-sensitive interpretation and development of urban air quality models in coastal urban settings.