## 1 Introduction
Particularly for local contracting authorities, the close proximity between buyers, suppliers, and end users [18] can provide complementarities for mission-oriented approaches to achieve sustainability goals through the use of GPP. With over half of the world's population located in urban centers, cities are a major contributor to greenhouse gas (GHG) emissions, while also having high potential to implement sociotechnical solutions to climate change mitigation and adaptation [19]. Municipalities could thereby benefit greatly from practicing mission-oriented GPP for sustainable urban development (SUD), where sustainability missions can be achieved through the incorporation of voluntary standards in public tenders [20,21] for public goods, services, and works. Currently, the European Commission is in the final stage of gathering stakeholder feedback on draft guidance for the public procurement of sustainable infrastructure, including co-creation of new solutions and recommendations [22]. This underscores the contemporary and international importance of the investigation of this paper. However, methods for mission-oriented approaches for empirical study, and particularly in the investigation of public procurement projects, are still in their nascency. Progress toward achieving missions is currently limited by the lack of methods by which to systematically incorporate green criteria within SUD projects, at both the project and the program level, as well as across different municipalities. As applied to GPP, this can leave procurers and project managers without the necessary tools by which to translate high-level missions into sustainability aspirations within the procurement process and engage stakeholders in achieving these goals. In turn, practitioners can miss opportunitiesto set the right demand to the market and to leverage the purchasing power of public procurement to its full potential. Theoretical understanding of these mechanisms is also limited, despite the practical implementation of missions across many policy domains. Of course, environmental policy approaches to public procurement and to greening private industry are nothing new--the Commission of the European Communities noted almost 30 years ago that \"Member States (and their public authorities) have, increasingly, started to integrate environmental considerations into their public procurement practices\" [23]. For example, the many European countries had implemented environmental management systems (EMS), and programs and methodologies to identify opportunities for improving emissions efficiency such Pollution Prevention Pays (PPP) in the Netherlands [24]. In a longitudinal review of GPP literature, [PERSON] et al. [25] found that the majority investigated GPP impacts, rather than any internal mechanisms of the procedure, and highlights the need for further research into the role of standards in GPP its innovation \"spillovers\". The current analysis extends upon recognition of the importance of private-sector innovation, voluntary standards, and effective regulation by focusing on public procurement strategies, which include these elements--and, critically, multiple (types of) stakeholders--in mission-oriented approaches toward sustainability goals. Therefore, this paper poses the following research question:  
_\"How can voluntary standards be used to help formulate and achieve missions for sustainable urban development at the municipal level?\"_  
Narrowing in on any special potential for GPP in particular, this paper also poses the following sub-question:  
_\"What role can green public procurement play in this process?\"_  
This paper conducts an empirical investigation into the formulation of complementary missions toward SUD, and the implementation of these missions in SUD projects at the municipal level. In answering the research question, this paper presents a first theoretical synthesis of GPP and MIS, examining the deployment of voluntary standards in GPP by public contracting authorities to achieve sustainability ambitions.