Resumen: Conventional spatial regression models are extended by modelling the spatial effects of the exogenous regressor model (SLX) as a functional coefficient. This coefficient is estimated by partitioning the domain of the spatial variable into a set of disjoint intervals and approximating the function using local Taylor expansions. The asymptotic properties of the proposed partitioning estimator are derived, and pointwise and uniform tests for the presence of spatial effects are developed. An empirical application of this work is used to study environmental Engel curves and provides strong evidence of neighbouring effects in the relationship between households’ income and the amount of pollution embodied in the goods and services they consume. Idioma: Inglés DOI: 10.1016/j.ecosta.2023.02.003 Año: 2026 Publicado en: Econometrics and Statistics 37 (2026), 126-153 ISSN: 2452-3062 Factor impacto CITESCORE: 3.1 - Economics and Econometrics (Q2) - Statistics, Probability and Uncertainty (Q2) - Statistics and Probability (Q2)