loading page

Diesel passenger vehicle shares influenced COVID-19 changes in urban nitrogen dioxide pollution
  • +6
  • Gaige Hunter Kerr,
  • Daniel L. Goldberg,
  • K. Emma Knowland,
  • Christoph A. Keller,
  • Dolly Oladini,
  • Iyad Kheirbek,
  • Lucy Mahoney,
  • Zifeng Lu,
  • Susan Anenberg
Gaige Hunter Kerr
George Washington University

Corresponding Author:[email protected]

Author Profile
Daniel L. Goldberg
George Washington University
Author Profile
K. Emma Knowland
Universities Space Research Association (USRA)/GESTAR, Columbia, MD, USA
Author Profile
Christoph A. Keller
Universities Space Research Association (USRA)/GESTAR, Columbia, MD, USA
Author Profile
Dolly Oladini
C40 Cities, London, England, UK
Author Profile
Iyad Kheirbek
C40 Cities Climate Leadership Group Inc., New York, NY, USA
Author Profile
Lucy Mahoney
C40 Cities, London, England, UK
Author Profile
Zifeng Lu
Systems Assessment Center, Energy Systems Division, Argonne National Laboratory, Lemont, IL, USA
Author Profile
Susan Anenberg
Department of Environmental and Occupational Health, Milken Institute School of Public Health, The George Washington University, Washington, DC, USA
Author Profile

Abstract

Diesel-powered vehicles emit several times more nitrogen oxides than comparable gasoline-powered vehicles, leading to ambient nitrogen dioxide (NO2) pollution and adverse health impacts. The COVID-19 pandemic and ensuing changes in emissions provide a natural experiment to test whether NO2 reductions have been starker in Europe, a region with larger diesel passenger vehicle shares. Here we use a semi-empirical approach that combines in-situ NO2 observations from urban areas and an atmospheric composition model within a machine learning algorithm to estimate business-as-usual NO2 during the first wave of the COVID-19 pandemic in 2020. These estimates account for the moderating influences of meteorology, chemistry, and traffic. Comparing the observed NO2 concentrations against business-as-usual estimates indicates that diesel passenger vehicle shares played a major role in the magnitude of NO2 reductions. European cities with the five largest shares of diesel passenger vehicles experienced NO2 reductions ~2.5 times larger than cities with the five smallest diesel shares. Extending our methods to a cohort of non-European cities from the C40 Cities network reveals that NO2 reductions in these cities were generally smaller than reductions in European cities, which was expected given their small diesel shares. We identify potential factors such as the deterioration of engine controls associated with older diesel vehicles to explain spread in the relationship between cities’ shares of diesel vehicles and changes in NO2 during the pandemic. Our results provide a glimpse of potential NO2 reductions that could accompany future deliberate efforts to phase out or remove passenger vehicles from cities.