EGU21-13246, updated on 26 Mar 2022
EGU General Assembly 2021
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

The impact of COVID-19 on CO2 emissions in the Los Angeles and Washington DC/Baltimore metropolitan areas 

Anna Karion1, Vineet Yadav2, Subhomoy Ghosh1,3, Kimberly Mueller1, Geoffrey Roest4, Sharon Gourdji1, Israel Lopez-Coto1, Kevin Gurney4, Nicholas Parazoo2, Kristal Verhulst2, Jooil Kim5, Steve Prinzivalli6, Clayton Fain6, Thomas Nehrkorn7, Marikate Mountain7, Ralph Keeling5, Ray Weiss5, Riley Duren8, Charles Miller2, and James Whetstone1
Anna Karion et al.
  • 1National Institute of Standards and Technology, United States of America (
  • 2Jet Propulsion Laboratory, California Institute of Technology, United States of America
  • 3University of Notre Dame, United States of America
  • 4Northern Arizona University, USA
  • 5Scripps Institution of Oceanography, USA
  • 6Earth Networks, Inc., USA
  • 7Atmospheric and Environmental Research, USA
  • 8University of Arizona, USA

Responses to COVID-19 have resulted in unintended reductions of city-scale carbon dioxide (CO2) emissions. Here we detect and estimate decreases in CO2 emissions in Los Angeles and Washington DC/Baltimore during March and April 2020. Our analysis uses three lines of evidence with increasing model dependency. The first detects the timing of emissions declines using the variability in atmospheric CO2 observations, the second assesses the continuation of reduced emissions using CO2 enhancements, and the third employs an inverse model to estimate the relative emissions changes in 2020 compared to 2018 and 2019. Emissions declines began in mid-March in both cities. The March decrease (25%) in Washington DC/Baltimore is largely supported by a drop in natural gas consumption associated with a warm spring whereas the decrease in April (33%) correlates with changes in gasoline fuel sales, a proxy for vehicular emissions. In contrast, only a fraction of the March (17%) and April (34%) reduction in Los Angeles is explained by traffic declines, while the remainder of the emissions reduction remains unexplained. To help diagnose such observed changes in emissions, more reliable, publicly available emission information from all significant sectors needs to be made available. Methods and measurements used herein highlight the advantages of atmospheric CO2 observations for providing timely insights into rapidly changing urban emissions patterns that can empower cities to course-correct mitigation activities more efficiently.

How to cite: Karion, A., Yadav, V., Ghosh, S., Mueller, K., Roest, G., Gourdji, S., Lopez-Coto, I., Gurney, K., Parazoo, N., Verhulst, K., Kim, J., Prinzivalli, S., Fain, C., Nehrkorn, T., Mountain, M., Keeling, R., Weiss, R., Duren, R., Miller, C., and Whetstone, J.: The impact of COVID-19 on CO2 emissions in the Los Angeles and Washington DC/Baltimore metropolitan areas , EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-13246,, 2021.


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