Regarding the data inconsistency from different data sources on emissions and ground-level pollutants’ concentrations in the atmospheric air over Ukraine

The development of action plans and strategies to reduce atmospheric air pollution requires the use of emissions and concentration data over extended periods. At such scales, the role of uncertainties increases, potentially leading to the development of ineffective measures. This article presents a study of the consistency of data from various sources, including official emissions inventories, modeled emissions data from the Copernicus Atmosphere Monitoring Service (CAMS), pollutant concentration data measured at stationary monitoring stations of hydrometeorological organizations, and ground-level content data from CAMS reanalysis for carbon monoxide (CO), nitrogen dioxide (NO2), and sulfur dioxide (SO2). The research revealed significant inconsistencies among different datasets, often reflecting entirely different interannual variability and trends. While emissions predominantly show a declining trend, concentrations in most cities continue to rise based on observational data and often show no significant changes according to reanalysis data. Notably, agreement between emissions data from different sources was found in only 12 cases across citypollutant pairs. Consistency in pollutant concentration data was identified in only 3 cities for CO and 4 cities for SO2. The differences in emission volumes, even where high correlations exist, can vary by an order of magnitude for certain cities. The article provides a list of cities for each of the studied pollutants where consistency between different data sources is observed, identifying cases where the data can be complementary or interchangeable. The study emphasized that this inconsistency has negative implications for the ability to assess interannual changes, the quality of modeling and data interchangeability, the verification of evaluation results regarding the effectiveness of air quality management measures, and a wide range of other consequences.