Concurrent Mobile–Aerial Monitoring of Landfill Methane Emissions

Methane (CH₄) emissions from the waste sector represent a substantial and addressable component of global greenhouse gas emissions, accounting for around 20% of total anthropogenic methane and ranking third after agriculture and fossil fuels. In Europe, landfills alone contribute approximately 30% of anthropogenic CH₄ emissions, drawing increasing attention due to CH₄’s high global warming potential and the relative feasibility and cost-effectiveness of mitigation measures in this sector. Accurate quantification of fugitive landfill methane is therefore critical, both for greenhouse gas mitigation and for evaluating the performance of gas recovery systems and bio-covers.

Recent advances in atmospheric methane measurement techniques have enabled high-resolution, in situ observations using mobile and aerial platforms. In this work, we present an integrated dual-platform approach that combines car-based mobile measurements with unmanned aerial vehicle (UAV) observations to improve the characterization of landfill methane emissions. By merging ground-level and aerial perspectives, this approach enhances spatial coverage and provides three-dimensional insight into plume behaviour, particularly in complex terrains where single-platform methods are often insufficient.

We demonstrate the methodology at the Kotsiatis landfill in Cyprus, a closed municipal waste site currently undergoing environmental rehabilitation. Three measurement campaigns conducted in 2025 captured methane emissions at different stages of post-closure works. During the December 2025 campaign, partner teams from the IM4CA project also participated, deploying two UAV teams alongside three instruments on the mobile platform.

We examine how differences in monitoring platforms, meteorological conditions (including wind, atmospheric pressure, and temperature), stage of post-closure works and flux estimation methodologies influence methane quantification results. This analysis provides critical insight into the strengths and limitations of mobile- and UAV-based approaches for landfill methane emission assessment and supports their effective application in complex real-world settings.