Potential of citizen science to advance urban planetary health research in low and middle-income countries: A scoping review.

Planetary health has emerged as a transdisciplinary field to capture the interdependencies between environmental changes and human health. Nowhere is this more critical than in the low- and middle-income country (LMIC) settings where the majority of the world's population live. These settings are undergoing rapid urbanisation that could further threaten planetary boundaries. The collaborative and societally engaged nature of planetary health means more participatory and dynamic methods are needed to better characterise these exposures. Citizen science has the potential to enable the co-production of community-relevant evidence but the extent to which this is being deployed for planetary health in LMIC cities has not been synthesised. To synthesise evidence on the use of citizen science for planetary health-relevant studies in urban LMIC settings, we conducted a scoping review, following the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews and Joanna Briggs Institute's stages of conducting a scoping review. Inclusion criteria included empirical studies in LMICs, with a focus on cities and published in English within the last 10 years. Of the 31 eligible studies included, the majority focused on biodiversity, illustrating the unharnessed potential of deploying citizen science to advance understanding of a broader range of planetary health variables in LMIC cities. Our finding of a predominance of Global North funding for these studies highlights the need for greater diversity of funding sources and for a shift in the centre of gravity of funding decisions to optimise alignment of research priorities with contextual realities in the Global South. To inform future research, we propose a standardised reporting format for citizen science planetary health projects and guidelines to optimise data reliability and validity.