Young children are actors usually excluded from political decisions and also from many science communication projects. Participatory science communication models can help to connect their everyday life with both local policies and science-related content. Using visual methodologies for engagement, we aimed at understanding what preschool children prefer in the city landscape. Results show how young children envision a “better city” and how that construction might defy current scientific knowledge. It further illustrates how science communication can be used to co-produce new knowledge, contributing to the debate about people's needs and perceptions related to science-based options.

Despite the societal relevance of energy research, there is a distinct lack of citizen science initiatives in the field. This paper reports the experience of a participatory and innovative strategy to develop a citizen science initiative for solar energy research. A number of stakeholders participated in the definition and implementation of the initiative, and tools such as surveys and a hackathon were employed. The process described aims to provide a blueprint for transforming the relationship between citizens and research into societal challenges. Here we describe the collaborative process and analyse the main opportunities, limitations and future perspectives.

Citizen science opens the scientific knowledge production process to societal actors. In this novel collaboration process, scientists and citizens alike face the challenge of new tasks and functions, eventually resulting in changing roles. Role theory provides a way of conceptualizing the roles that people take in communication and interaction. We use role theory to create a framework that identifies scientists' and citizens' tasks in citizen science projects, main aims of communication, spaces they interact in, and their roles — thus providing a structured way to capture communication and interaction in and about CS for further scientific reflection and practical application.

Despite being a critical environmental problem, soil pollution is not usually considered as a relevant issue by the general public. This disinterest derives from traditional procedures to assess soil pollution that are quite complex and costly, not considering any form of citizen involvement. Seeking to challenge this situation, the project “Nuestros Suelos” (Our Soil) aimed at designing and testing a low-cost participative soil pollution assessment toolkit. The final prototype included several participative modules, going from an assessment of the history of local soils to measuring heavy metals such as Arsenic and Copper. Tested with low-income communities in northern Chile, the toolkit was able not only to produce multiple kinds of data but also a public that started to understand and care about the issue.

Co-creation aims at integrating citizens in the entire research process. The citizen linguistics project German in Austria tests this approach in the humanities based on the assumption that language is ubiquitous. The project combines different forms of public participation, including a co-created format, where citizens can raise (and answer) research questions about the German language in Austria and a linguistic treasure hunt, where citizens collect and analyze data on linguistic landscapes. However, co-creation was hard to implement. Despite a high number of participants, their willingness to contribute to more than one research step was low.

Citizen science (CS) is promoted as a useful practice for the achievement of the Sustainable Development Goals (SDGs). In this contribution we explore how CS aligns to the SDGs overarching pledge to ‘Leave no one behind’. We propose a framework to evaluate exclusionary processes in CS. We interlink three dimensions of CS inspired by existing CS typologies with five factors underpinning exclusionary processes. With this, we are able to situate existing literature on various exclusionary effects in CS within a structured framework. We hope this contribution sparks a discussion and inspires practitioners’ reflections on a more inclusive practice in CS.

Undertaking citizen science research in Public Health involving human subjects poses significant challenges concerning the traditional process of ethical approval. It requires an extension of the ethics of protection of research subjects in order to include the empowerment of citizens as citizen scientists. This paper investigates these challenges and illustrates the ethical framework and the strategies developed within the CitieS-Health project. It also proposes first recommendations generated from the experiences of five citizen science pilot studies in environmental epidemiology within this project.

Marine research is as important as very demanding since it requires expensive infrastructures and resources. Scientific institutions, on the contrary, have very limited funding so that the seas remain, still, mostly unexplored. Another serious concern is that society at large often resonates with fake news, while scientists sometimes tend to bias research with their backgrounds and paradigms. We think that all these issues can be addressed opening the process of knowledge building to the questions and needs of stakeholders and laypeople. The MaDCrow project proposed and tested several paths to attain these goals.

Understanding scientific concepts is a crucial factor in motivating dabblers at the start of co-created citizen science projects. This article describes PACMAC, a card-based cooperative card game aimed at introducing dabblers to hypothesis and falsifiability concepts through the visualization of a social perception map. The game was evaluated in five neighborhoods from El Salvador. The results showed that PACMAP is approachable for participants of different demographics to develop an understanding of the concepts of hypotheses and falsifiability.

Over 500 delegates took part in the third international ECSA conference in September 2020. Across 30 sessions, as well as keynote talks, e-poster presentations and more informal settings, they discussed and debated a diverse range of subjects related to citizen science. This special edition of ‘JCOM’ brings together some of the central themes that were under the spotlight at ECSA 2020. Since ECSA 2020 has been one of the first examples of a conference that moved completely online, and it has been considered a big success, we also include the Conference Report, as supplementary material with this editorial.