This paper is about the power to represent. ‘Who speaks for Teesside?’ about air pollution – whose voice gets heard about the sources, pathways and consequences of pollution. Around such apparently technical issues arises a kind of political morality tale that leads to questions of security and insecurity, accountability and trust. Industry and local government in Teesside may no longer have things their own way; but they have been tenacious in resisting what they consider to be unhelpful claims or assumptions about pollution and its impact, and there are strong reasons why they are able to claim that they present the authoritative account of Teesside's air quality. In conclusion some changes to the context in which industrial pollution comes to the fore as a public issue are reviewed: debate around diversification of Teesside's economy; the impact of environmental campaigns; and certain paradoxes of developments in air quality monitoring.