The authors draw upon survey evidence of expert conceptualisations of the value of public knowledge in environmental decisionmaking. In the context of local air quality management in particular, they consider how experts understand the potential benefits of technological citizenship, and what status they accord to lay knowledge relative to their own roles. Evidence suggests a continuing expert-deficit model of lay knowledge, with suspicions that the public misunderstand environmental issues. Although the need for public 'buy-in' to the solutions to problems such as air pollution is supported, this does not translate to a more proactive engagement of lay knowledge in the assessment of such issues. Experts seem to be personally challenged by such notions. The authors discuss the need for a cultural shift in expert understanding of the value of lay knowledge, supported by a move away from an oversimplification of the need for, and value of, public participation.