The Radon Tracer Method (RTM) is a top-down approach to estimate greenhouse gas emissions. While simple in principle, incorrect use can complicate interpretation of results. Based on observations from a range of contrasting sites, this article reviews the underlying assumptions and key considerations for applying the RTM. It also introduces the concept of coupling RTM analyses with nocturnal stability classification, to reduce uncertainty of fetch estimates and improve interpretation of results.

This study explores new ways to better understand urban air pollution by combining traditional monitoring with portable sensors, mobile measurements, and public participation. Using European city case studies, the research shows that these approaches can identify pollution hotspots in greater detail and make air quality information more accessible to communities and decision-makers. The work highlights how improved monitoring supports healthier cities and more effective environmental policies.