This collection contains hourly averaged greenhouse gas observations of CH₄ and CO₂ at five stations in the Barcelona metropolitan area, starting in May 2021. In addition, one of the stations also provides CO observations.

These measurements are performed by ICTA-UAB in the framework of the ERC URBAG project (https://urbag.eu/), contribute to the ICOS Cities (also known as PAUL) project (GA 101037319), to to ICTA-UAB “María de Maeztu” Programme for Units of Excellence of the Spanish Ministry of Science, Innovation and Universities (CEX2024-001506-M funded by MICIU/AEI/10.13039/501100011033), and to GASPOF (Pervasive gas sensing using optical fibers, as part of the communication network of the future, project #101189654) funded by the European Union (HORIZON-CL4-2024-DIGITAL-EMERGING-01-54).

Measurements are carried out using Picarro CRDS instruments. Instrument drift is monitored using a daily target tank, and calibration is performed every 2–3 weeks. The working standards are calibrated against NOAA secondary standards.