Changes in greenhouse gas emissions observed in Indianapolis, IN during the COVID-19 shutdown

Abstract:

The lockdown necessitated by the COVID-19 pandemic had obvious implications for human behavior, the economic sector, and a reduction in emission of greenhouse gases (GHG). Traffic patterns, for example, drastically decreased compared to early March 2020 and are gradually returning to pre-COVID levels. This particular event is an opportunity to evaluate the ability of tower-based measurements of GHG to quantify rapid changes in emissions. The Indianapolis Flux Experiment (INFLUX) is a project with in-situ towers deployed across Indianapolis, Indiana, with multiple years of continuous measurements of GHG. Using this extensive dataset, we explore observational approaches to determine the changes in the GHG mole fractions during the COVID-19 pandemic. We analyze the behavior of such changes across the years and its signature during 2020, demonstrating the complications caused by temporal variations in meteorology and biology. Preliminary results show that, compared to previous years (2013 to 2019), one of the towers in Indianapolis, located at an intersection of a highway, had enhancements reduction of 18.8% (±17.2) in CO₂ (25.6%±23.8 in CO) and vertical gradients reduction of 45.9% (±29.5) in CO₂ (45.4%±23 in CO) during morning rush hours. During the afternoon rush hours, enhancements decreased 23.2% (±17.2) in CO₂ (41.9%±12.3 in CO) and vertical gradients of CO₂ (CO) reduced 53.1% ±7.8 (54.3%±8.8). Uncertainties represent one standard deviation of the mean.

We are working toward a description of the changes in GHG emissions caused by the shutdown. Our results, so far, demonstrate some methodological tools needed to extract the signature of this shutdown and yield insights into the measurement networks required to quantify rapid temporal changes in emissions.