Analyzing the impact of COVID-19 on tropospheric NO2 using Pandora observations across North America

Abstract:

As the primary precursor to ozone production, NO₂ exhibits large amounts of heterogeneity on vertical and horizontal scales. The global COVID-19 pandemic has led to significant changes in human behavior due to lockdown restrictions. This has led to well documented decreases in NO₂ pollution worldwide based on daily satellite observations. While satellite observations of NO₂ from polar orbiting satellites (TROPOMI, OMI, etc) provide a unique high resolution spatial perspective, these satellites only provide a once daily snapshot. Pandora, a ground based spectrophotometer, allows us to measure column NO₂ at a much higher temporal resolution that is on a similar scale to that of a traditional in-situ surface NO₂ monitor. To quantify the changes in NO₂ due to COVID19 from a ground based perspective, we utilize a combination of Pandora and in situ observations to investigate the changes in surface and column NO₂. Using the combination of these observations we will provide better insight into changes in the diurnal variation of NO₂. The results of this study are essential for understanding the sensitivity of column measurements to emission changes and for better interpreting future geostationary air quality observations.