Integration of Multi-Gas Sensors and Aerial Thermography into UAVs for Environmental Monitoring of a Landfill

Landfills are a significant source of atmospheric emissions associated with the decomposition of organic waste; however, conventional monitoring methods typically have limited spatial coverage. This study evaluates the use of an UAV-based system for the spatial characterization of gases associated with biogas emissions at a municipal landfill. A DJI Matrice 350 RTK platform equipped with a Sniffer4D Mini2 multi-gas station and a Zenmuse H20T thermal camera were used. Four flight campaigns were conducted at an altitude of 20 m, with an acquisition frequency of approximately 1 Hz, recording total hydrocarbons (CxHy) as an indirect indicator of methane (CH4), carbon dioxide (CO2), carbon monoxide (CO), nitrogen dioxide (NO2), ozone (O3), sulfur dioxide (SO2), oxygen (O2), temperature, and relative humidity. The results showed a marked transition around 13:10 h, characterized by a simultaneous increase in CH4 equivalent and CO2, along with a decrease in NO2, O3, and SO2. Furthermore, CH4 equivalent and CO2 showed the highest positive correlation among the variables (r = 0.96). Spatial maps generated using ordinary kriging revealed more heterogeneous patterns, while the qualitative thermal orthophoto confirmed the site’s surface variability. Overall, the results demonstrate that the integration of multi-gas sensors and aerial thermography on UAVs is viable for the spatial monitoring of landfills.