The focus of this study was to assess the influence of dispersion conditions represented by ventilation coefficient on speciated PM10 concentrations measured every 4 h for three years (2021–2023) and their origins at the National Atmospheric Observatory Košetice (NAOK). The interquartile range (IQR) of dispersion normalised PM10 tracer concentrations was lower in comparison with the IQR of non-normalised concentrations with a significant seasonal effect of dispersion normalisation differentiated element by element. PMF resolved five factors of PM10 for both datasets (non-normalised and normalised) with almost identical chemical profiles. Dispersion normalisation provided improved source apportionment results with clearer diel and seasonal patterns primarily for secondary sulphate and residential heating, therefore the main sources of elemental PM10.