In the reference period, there were 7 days with KBI values indicating very low air pollution (KBI 1), and 23 days with slightly higher pollution levels (KBI 2). There were no days with KBI values greater than or equal to 4, suggesting that air pollution levels did not reach high levels. The mean concentrations of pollutants were 41.9 µg/m³ for O3, 9.2 µg/m³ for NO2, and 7.6 µg/m³ for PM10, with maximum values of 115.9 µg/m³, 28.9 µg/m³, and 33.5 µg/m³ respectively. There were no exceedances recorded for NO2, O3, or PM10.

Comparing the data from the reference period with previous years for the same month, the air pollution levels in 2025 were generally lower. The mean concentrations of O3, NO2, and PM10 were lower than in most previous years, and there were no exceedances recorded, unlike some previous years. For instance, in 2018 and 2020, there were several O3 exceedances, and the mean O3 levels were significantly higher. The number of days with very low pollution (KBI 1) was also higher in 2025 compared to most previous years, indicating an improvement in air quality. Overall, the air pollution in the reference period was lower than in previous years.