Replication Data for: Active face emissions: An opportunity for reducing methane emissions in global waste management

This dataset describes raw mobile methane (CH₄) measurements collected by FluxLab during multi-day surveys at ten Canadian municipal solid-waste landfills in Nova Scotia, Quebec, and Alberta in 2023–2024. Surveys were carried out using repeated on-site, fenceline, and off-site public-road transects and stationary downwind holds, under different wind conditions, to pass through or intercept plumes at varying distances. The measurement vehicle was equipped with a Gill WindSonicM ultrasonic anemometer (wind speed accuracy ~3% and direction ±3°), an RM Young 32500 electronic compass (±2°), a Garmin 18x 5 Hz GPS, and Los Gatos Research analyzers (UGGA or LGR-ICOS Microportable GLA131; CH₄ precision ~1.4 ppb for the Microportable). Prior to each day’s measurements, analyzers were checked against certified reference gases, the compass was verified using the four cardinal directions, and the inlet-to-analyzer transit time was measured and applied to correct timestamps. Calibration gases were referenced to WMO mole-fraction scales (X2004a for CH₄; X2019 for CO₂). Data were logged on a common, synchronized timebase with standardized QC steps (timestamp sync, GPS correction, wind-vector correction for vehicle motion, instrument-lag correction, and basic completeness checks). Each CSV provides timeseries of CH₄ (and CO₂ when available), wind speed/direction corrected for vehicle motion, GPS, and nearby METAR weather matches. All site coordinates are anonymized, longitude_anon and latitude_anon, are intentionally offset and do not represent real locations; they’re only for visualization and relative spatial context, not for mapping or navigation to actual sites. Files are named [YYYY-MM-DD]_LFID_anonymized.csv, where the date comes from the measurement day and LFID is an anonymized landfill ID (LFID1–LFID10). Note that only the downwind portions of the measurements were used in our analyses; the full shared files include records that may not have been analyzed. This project was supported by Natural Resources Canada.