| Autor: |
Karion A; Special Programs Office, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States., Ghosh S; Special Programs Office, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States.; Center for Research Computing, University of Notre Dame, South Bend, Indiana 46556, United States., Lopez-Coto I; Special Programs Office, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States.; School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, New York 11794, United States., Mueller K; Special Programs Office, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States., Gourdji S; Special Programs Office, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States., Pitt J; School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, New York 11794, United States.; School of Chemistry, University of Bristol, Bristol BS8 1QU, U.K., Whetstone J; Special Programs Office, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States. |
| Abstrakt: |
Urban methane emissions estimated using atmospheric observations have been found to exceed estimates derived by using traditional inventory methods in several northeastern US cities. In this work, we leveraged a nearly five-year record of observations from a dense tower network coupled with a newly developed high-resolution emissions map to quantify methane emission rates in Washington, DC, and Baltimore, Maryland. Annual emissions averaged over 2018-2021 were 80.1 [95% CI: 61.2, 98.9] Gg in the Washington, DC urban area and 47.4 [95% CI: 35.9, 58.5] Gg in the Baltimore urban area, with a decreasing trend of approximately 4-5% per year in both cities. We also find wintertime emissions 44% higher than summertime emissions, correlating with natural gas consumption. We further attribute a large fraction of total methane emissions to the natural gas sector using a least-squares regression on our spatially resolved estimates, supporting previous findings that natural gas systems emit the plurality of methane in both cities. This study contributes to the relatively sparse existing knowledge base of urban methane emissions sources and variability, adding to our understanding of how these emissions change in time and providing evidence to support efforts to mitigate natural gas emissions. |
