Comparing EMEP4PL and uEMEP models performance for PM2.5 and NOx for Poland 

Nowadays, environmental studies emphasize that the advancement of atmospheric transport models will persist as a significant challenge in environmental modeling for the forthcoming decades. The obtained results are increasingly instrumental in air pollution epidemiology, health burden assessment, and evaluating exposure to air pollution. In this work we have run the regional EMEP4PL atmospheric transport model, with 4km x 4km resolution with high-resolution uEMEP model (250m x 250m) for the area of Poland. The models were run for the entire year of 2022. For the first time, these two models were run using a consistent, high-resolution national emission inventory. We have analyzed two pollutants harmful to population health: PM2.5 and NOx, and qualitatively compared the differences in spatial distribution of pollutant concentrations calculated by uEMEP and EMEP4PL. The uEMEP model shows higher concentrations for the emission hot spot areas, which are averaged out in the coarse-resolution EMEP4PL model. This is observed for both PM2.5 and NOx and is noticeable especially for the areas with large spatial gradient of emission (e.g. large cities or along the main roads). The results were also compared with available measurements of PM2.5 and NOx from the national air quality network operated by Chief Inspectorate for Environmental Protection (CIEP). For PM2.5, we have additionally used the measurements from the national air quality network operated by Chief Inspectorate for Environmental Protection (CIEP) and from the low-cost sensors network established within the LIFE-Mappingair project. The results show that the uEMEP model concentrationsresults are closer to the measurements for both networks. For NOx, uEMEP is also closer to the measurements, and the differences between the uEMEP and EMEP4PL performance are larger if compared to the PM2.5.