Quantifying urban and landfill methane emissions in the United States using TROPOMI satellite data
- Xiaolin Wang
- Daniel J. Jacob
- Hannah Nesser
- Nicholas Balasus
- Lucas A. Estrada
- Melissa P. Sulprizio
- Daniel H. Cusworth
- Tia R. Scarpelli
- Zichong Chen
- James D. East
- Daniel J. Varon
2026-03-25
Urban areas are major sources of population-driven methane with high potential for mitigation, but emission quantification and sectoral attribution remain uncertain. Using satellite observations and a high-resolution (12 kilometers by 12 kilometers) atmospheric inversion framework, we find that emissions from 12 major US urban areas are 80% higher than the US Environmental Protection Agency Greenhouse Gas Inventory (EPA GHGI), with up to four times higher emissions in Houston but 32 to 37% lower emissions in Los Angeles and Cincinnati. Landfills are the principal cause of inventory underestimates, with city-level management practices driving large variations in per capita emissions. Examination of individual landfills with gas collection systems shows gas collection efficiencies averaging 38% (range: 5 to 90%), much lower than their reported average of 70% (range: 40 to 87%). An exception is Los Angeles, where we find landfill gas collection averaging 85%, suggesting large urban methane mitigation potential through improved landfill management.