THE USE OF REMOTE SENSING OF ATMOSPHERIC COMPOSITION FOR BURNING EFFICIENCY ESTIMATION FOR UKRAINIAN TERRITORY

Abstract

Ratios of chemical compounds in the atmosphere are becoming more widely used for assessment of changes in fuel consumption by cities or specific industrial objects, as well as for correction of emission factors, which are crucial for emission inventories. The methodology for using the NO2/CO ratio for analysis of burning efficiency based on remote sensing data was first implemented for Ukrainian territory. We selected seven case studies for analyses, including three days for Kyiv with a variety of emission sources, two days for Mariupol with prevailing coal-fired industrial facilities, and two days for wildfires as reference cases for comparison. We use NO2 and CO column number densities derived from the TROPOspheric Monitoring Instrument (TROPOMI) onboard the Sentinel-5 Precursor, supported by the boundary layer height and wind parameters from the ERA-5 reanalysis. The overall methodology for NO2/CO estimation includes data quality analysis using cloudiness and a quality assurance index; meteorological data processing for obtaining the prevailing wind field at the top of the boundary layer; retrieving NO2 and CO content from emission sources and background values; and the NO2/CO ratio computation itself. For selected cases, the NO2/CO ratio equals 2.6 to 6.5 for wildfires, 3.1 to 4.6 for Mariupol, and 10.8 to 31.7 for Kyiv. Because of the available uncertainties, the necessity of estimating the NO2/CO ratio using longer time series is emphasized. The prospects for using the NO2/CO ratio are possibilities for the computation of emission factors and detecting the mass of pollutants emitted in Ukrainian cities. The NO2/CO ratio can be used as an additional parameter for assessing the changes in fuel consumption, considering the war consequences in Ukraine.