Growing awareness of the health and environmental burden of air pollution combined with access to new low cost air pollution monitors has helped drive the explosion of citizen science initiatives. Despite this momentum, there remains little public attention to the sources or drivers of air pollution. Without greater emphasis on source awareness, scientists or community members using citizen science techniques cannot effectively identify or target interventions that cut emissions or build pressure for policies that hold specific polluters accountable to legal pollutant limits or best practices.

To help understand how citizen science initiatives reflect or focus on sources of air pollution, this paper presents reflections from a purposive literature review of 33 case studies. Specifically it provides insights and a typology of citizen science initiatives that characterise how citizen science initiatives impact air pollution sources and provides recommendations for future approaches that could strengthen participatory science focused on pollution sources.

Key findings:

• Despite the growing number of citizen science projects designed to investigate air pollution and related health concerns, the public still lacks a clear shared understanding of where air pollution comes from—the relevant sources of emissions. This lack of source awareness can impede clear air action in various ways.
• The review revealed that these initiatives not only help increase public knowledge, but identify new hyperlocal sources, strengthen source-specific enforcement action, tie exposure and health impacts to specific emissions sources, and spur stronger compliance by polluting companies.
• Common features in achieving clear outcomes included taking time to build trust, a commitment to joint scientist-civil society leadership, and defining clear ways to use data.