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

Published

June 7, 2021

Author(s)

Kimberly Mueller, Anna Karion, Sharon Gourdji, Israel Lopez Coto, James Whetstone, Vineet Yadav, Geoffrey Roest, Kevin R. Gurney, Kristal R. Verhulst, Jooil Kim, Michael Stock, Elizabeth DiGangi, Steve Prinzivalli, Ralph Keeling, R. F. Weiss, Charles E. Miller, Clayton Fain, Riley Duren, Subhomoy Ghosh

Abstract

Responses to COVID-19 has resulted in and 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 the event using the variability in atmospheric CO2 observations, the second evaluates CO2 enhancements to assess the persistence of reduced emissions, and the third employs an inverse model to estimate the relative changes in emissions 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 explained by a drop in natural gas consumption associated with a warm spring whereas the decrease in April (33%) is mainly explained by changes in gasoline fuel sales. In contrast, the March (17%) and April (34%) decreases in Los Angeles are only partially explained by traffic reductions, highlighting the need for reliable, publicly emission information from other emission sectors. Our findings underscore the need to account for impacts on emissions that are unrelated to the pandemic or poorly understood at sub-annual scales. The results also highlight the advantages of atmospheric CO2 observations for providing low-latency insights into rapidly changing urban emissions patterns. Timely emission data can help cities assess their ability to drive down CO2 emissions and meet mitigation goals.

Citation

Proceedings of the National Academy of Sciences of the United States of America

Pub Type

Journals

Download Paper

https://doi.org/10.1029/2021GL092744

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Keywords

COVID-19, greenhouse gas, fossil fuel, urban, atmospheric inversion, change detection, CO2, atmospheric CO2 observations

Citation

Mueller, K. , Karion, A. , Gourdji, S. , Lopez Coto, I. , Whetstone, J. , Yadav, V. , Roest, G. , Gurney, K. , Verhulst, K. , Kim, J. , Stock, M. , DiGangi, E. , Prinzivalli, S. , Keeling, R. , Weiss, R. , Miller, C. , Fain, C. , Duren, R. and Ghosh, S. (2021), The impact of COVID-19 on CO2 emissions in the Los Angeles and Washington DC/Baltimore metropolitan areas, Proceedings of the National Academy of Sciences of the United States of America, [online], https://doi.org/10.1029/2021GL092744, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=931516 (Accessed October 14, 2025)