Measurement of Methane Concentrations at Ground Level in Bucharest during August 2024 Using a Mobile Laboratory

Methane (CH₄) is a significant greenhouse gas, playing a critical role in air quality and climate change. In situ measurements of CH₄ in Romania are very scarce. This study presents results from a ground-level measurement campaign of atmospheric methane concentrations in Bucharest, Romania. One of the main objectives was to map the spatial distribution of methane concentrations. The campaign was performed using a mobile laboratory, between August 6 and 27, 2024 and covered over 1500 km throughout Bucharest. Methane concentrations were measured using a Sniffer4D TDLAS analyzer with a resolution of 1 ppm. Bucharest was divided into three zones: northwest, northeast, and south. A designated route was established for each zone and crossed a total of 4 times: once at night and during the daytime over 3 different days. This data collection approach ensured statistical consistency and captured temporal and spatial variations in methane concentrations.

The results are presented as grid maps to highlight significant diurnal and spatial variations more clearly, indicating anthropogenic contributions from traffic and industrial activities during the day. At night, concentrations exhibited a more uniform distribution, suggesting relatively constant background emissions and a reduced influence of local activities.

This study contributes to understanding methane levels and sources in the urban environment of Bucharest and provides a critical reference for future monitoring efforts. The findings emphasize the importance of continuous methane concentration surveillance to support air quality management strategies and climate change mitigation.