The end of the line: An ameliorative approach to the concept of pollution

Pollution has become a central concept in environmental science, law and politics. However, upon closer scrutiny, the current conceptualisation of pollution proves inadequate. Threshold models, dominant in twentieth-century environmental science, conceptualise pollution as a scalar phenomenon: substances become pollutants when their concentration exceeds an acceptable limit. While pragmatically useful for regulation, this model faces three major issues: vagueness, discreteness and monotonicity. Threshold theory reduces pollution to measurable harm and one sole quantifiable dimension, although pollution encompasses other dimensions. It can also be relational, symbolic or political. Moreover, scalar frameworks risk collapsing complex, situated harms into a single technical metric through pernicious reification and ontological flattening. In this article, we argue that pollution is best understood as a thick, multi-dimensional concept whose descriptive and evaluative aspects are inseparable. Using conceptual engineering, we propose a five-dimensional model of pollution: scalar, symbolic, political, ecological and corporeal. By adopting this dimensional approach, we not only clarify the concept but also preserve its normative character. Thus, re-engineering pollution as a relational, multi-dimensional concept can provide conceptual clarity and foster interdisciplinary research.