Trends in CH 4 Emission Sources in the Los Angeles Basin from 2010 to 2023 Using Airborne Measurements
Year: 2025
Type: article
Abstract: High Resolution Image Download MS PowerPoint Slide California legislation mandates a 40% reduction in CH 4 emissions from 2013 levels by 2030. Achieving this requires an accurate inventory of greenhouse gas sources, including urban CH 4 . This study determined summertime CH 4 and C 2 –C 5 alkane emissions from the Los Angeles (L.A.) Basin using airborne field campaign measurements from 2010, 2019, and 2023. Our analysis combined enhancement ratios of CH 4 and alkanes versus CO from in situ airborne measurements with the California Air Resources Board’s CO emissions inventory. By incorporating known alkane abundances from various sectors, we apportioned the emission sources. We found an annual decline in CH 4 emissions from the L.A. Basin at a rate of −7.2 ± 5.8 Gg/year, consistent with literature and ground-site measurements from the Mount Wilson Observatory. The primary CH 4 sources were natural gas (52–57% of total emissions) and CH 4 -dominant sources, like landfills and dairies (41–47%). We also observed an annual increase in ethane emissions of 0.13 ± 0.19 Gg/year, which correlates with increasing ethane abundance in pipeline natural gas and decreasing ethane prices. If this linearly decreasing CH 4 emission trend were to continue, the L.A. Basin would be on track to reach the state’s 2030 CH 4 emission reduction goals.
Authors: Nell B. Schafer, Jeff Peischl, Eric C. Apel, Barbara Barletta, Donald R. Blake, Pawlok Dass, Joshua P. DiGangi, Glenn S. Diskin, Colby Francoeur, Alan Fried, Jessica B. Gilman, Kevin Gurney, Colin Harkins, Rebecca S. Hornbrook, Xin Lan, Aaron Lamplugh, Meng Li, Simone Meinardi, John B. Nowak, Gabrielle Pétron, Dirk Richter, Morgan Selby, Vanessa Selimovic, Victoria Treadaway, James Walega, Petter Weibring, Caroline Womack, Steven S. Brown
Institutions: Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, NOAA Chemical Sciences Laboratory, NSF National Center for Atmospheric Research, NSF NCAR Atmospheric Chemistry Observations & Modeling, University of California, Irvine, Northern Arizona University, Langley Research Center, Institute of Arctic and Alpine Research, National Oceanic and Atmospheric Administration, NOAA Global Monitoring Laboratory, University of Michigan
Language: English
Subfield: Global and Planetary Change
Field: Environmental Science
Domain: Physical Sciences
SDG: Climate action
Open Access status: hybrid
Estimated APC paid: $4,500
Funders: National Science Foundation, National Aeronautics and Space Administration, National Center for Atmospheric Research, California Institute of Technology, Colorado Department of Public Health and Environment, Northern Arizona University, Cooperative Institute for Research in Environmental Sciences, National Oceanic and Atmospheric Administration, Langley Research Center, University of Colorado Boulder, University of California, Irvine
OpenAlex ID: W4416816991