What is sustainable air quality?

For 40 years or more, air quality policy has been based on the paradigm of the air quality standard as a uniform criterion of acceptable environmental degradation, built on the foundations of the precautionary principle. However, developments in health science have undermined some of the underlying assumptions of this paradigm whilst technological emission controls have been offset by growing economic activity. Current trends are towards increasingly demanding notions of what constitutes acceptable air quality. Proposed future air quality standards could require a revolution in urban form and infrastructure. We need a new paradigm - sustainable air quality. In this paper, we discuss the need for a new paradigm of sustainable air quality management, its basis and what it might hope to achieve, including how further downward pressure can be exerted on emissions through urban form, urban design, transport policy and projects, energy strategy, etc.