In this chapter, the fundamental debate currently ongoing on the role of expert and lay knowledge in risk governance is explored. A ‘theory of change’ is outlined by hypothesizing a new approach to risk governance based on citizen sensing, and inspecting its theoretical grounding and the need for empirical analysis. Here, the literature review is complemented by three in-depth, semi-structured, face-to-face expert interviews. The experts came from the policy sector and from academia, respectively an expert of Risk Governance and an expert of Citizen Science from the Dutch National Institute for Public Health and the Environment (RIVM), and an expert of Responsible Innovation and of Urban Innovation theories from Delft University of Technology. These experts are interviewed to get insights from the institutional arena and from the academic sector on the potential of citizen sensing for environmental risk governance, within the framework of innovation in governance of environmental and public health issues.