A027-03
Assessment of the Quality of TROPOMI High-spatial-resolution NO2 Data Products and COVID-19 Lockdown Air Quality Changes in the Greater Toronto Area
Monday, 7 December 2020: 20:44
Virtual
Xiaoyi Zhao1, Debora Griffin1, Vitali E. Fioletov1, Chris A McLinden1, Alexander Cede2, Martin Tiefengraber3, Moritz Mueller3, Kristof Bognar4, Kimberly Strong5, Folkert Boersma6, Henk Eskes7, Jonathan Davies1, Akira Ogyu8, Sum Chi Lee8 and Dan Weaver9, (1)Environment and Climate Change Canada, Air Quality Research Division, Toronto, ON, Canada, (2)LuftBlick, Innsbruck, Austria, (3)LuftBlick, Mutters, Austria, (4)University of Toronto, Physics, Toronto, Canada, (5)University of Toronto, Department of Physics, Toronto, ON, Canada, (6)KNMI, Brussels, Belgium, (7)Royal Netherlands Meteorological Institute, De Bilt, 3730, Netherlands, (8)Environment and Climate Change Canada, Air Quality Research Division, Toronto, Canada, (9)University of Toronto, Toronto, ON, Canada
Abstract:
The TROPOspheric Monitoring Instrument (TROPOMI) is a nadir-viewing spectrometer
on the Sentinel-5P satellite measuring reflected sunlight from the ultraviolet to shortwave infrared spectral ranges.
Total columns of trace gases, including nitrogen dioxide (NO2), are retrieved from the measured spectra
. In this work, Pandora NO2 measurements made at four sites located in or north of the Greater Toronto Area (GTA) are used to evaluate two TROPOMI NO2 data products: 1) the standard Royal Netherlands Meteorological Institute (
KNMI) NO2 data product and 2) a research data product developed by Environment and Climate Change Canada (ECCC) using a high-resolution regional air quality forecast model (used in the airmass factor calculation)
.
TROPOMI pixels located upwind and downwind from the Pandora sites were analyzed using a new wind-based validation method that increases the number of coincident measurements by about a factor of five compared to standard techniques. This work shows that both TROPOMI and Pandora instruments can reveal detailed spatial patterns (i.e., horizontal distributions) of local and transported NO2 emissions, which can be used to evaluate regional air quality changes. The TROPOMI ECCC NO2 research data product shows improved agreement with Pandora measurements compared to the TROPOMI standard tropospheric NO2 data product, demonstrating the benefit of using the high-resolution regional air quality forecast model to derive NO2 airmass factors. More recent measurements before and after the lockdown of the GTA due to COVID-19 will also be presented. Preliminary results from Pandora measurements show that the major city airport of Toronto has reduced NO2 emissions by at least 40% in the first three months of the lockdown.
