The role of fine and submicron aerosol particles in urban air pollution in the context of meeting new air quality standards.

Despite extensive efforts in ​​reducing emissions related to road traffic, industrial, and household activities, the problem of exceeding standard levels of particulate matter (PM) still affects many areas in Europe. The monitoring data for the PM1, PM2.5, PM10, PM10 - 18, as well as the particle number, at urban background site in Zabrze (Southern Poland) over a 3-year period (Jun 2022 - May 2025) are presented within this paper. The main goal of the study was to analyse the concentrations of and contributions of various fractions of the total suspended particulates (TSP), together with the assessment of their time variability and their role in air pollution of an urban area. It was found that the annual average levels of both PM2.5 and PM10 remained high compared to the values recorded at many European measurement stations. Moreover, for a large part of the research period, daily PM2.5 and PM10 concentrations were above the revised daily standard (~ 30% and ~ 17%, respectively). During the study, a total of 109 exceedances of the level of 50 µg m- 3 were identified, of which 84 were classified as episode days (26 events in total). Regardless of the averaging period, PM2.5-especially PM1-constituted the dominant part of the TSP with a particularly high share in the winter months and in episodes (~ 80%). Therefore, the obtained results indicate the need to include PM1 measurements in routine air quality monitoring and the necessity to establish exposure limits for this fraction, especially in areas where the PM2.5 limit values ​​are frequently exceeded.