Particulate matter (PM) air pollution in the urban environment is mainly related to the presence of potential sources throughout the year. Road transport is one of the most important sources of PM in the urban environment, because it directly affects pedestrians. PM measurements were performed in the city of Žilina, Slovakia, at various road-traffic-related measurement stations over the course of several years. This paper evaluates changes in the concentration of the fine fraction (PM_2.5), the ultrafine fraction (PM₁), and the coarse fraction (PM_2.5–10) over time. PM concentrations were measured by reference gravimetric method. Significant changes in PM concentrations over time due to the diversification of pollution sources and other, secondary factors can be observed from the analysis of the measured data. PM samples were subjected to chemical analysis inductively coupled plasma mass spectrometry (ICP-MS) to determine the concentrations of elements (Mg, Al, Ca, Cr, Cu, Fe, Cd, Sb, Ba, Pb, Ni, and Zn). The seasonal variation of elements was evaluated, and the sources of PM_2.5, PM₁, and PM_2.5–10 were estimated using principal component analysis (PCA) and positive matrix factorization (PMF). PM_2.5 (maximum concentration of 148.95 µg/m³ over 24 h) and PM₁ (maximum concentration of 110.51 µg/m³ over 24 h) showed the highest concentrations during the heating season, together with the elements Cd, Pb, and Zn, which showed a significant presence in these fractions. On the other hand, PM_2.5–10 (maximum concentration of 38.17 µg/m³ over 24 h) was significantly related to the elements Cu, Sb, Ba, Ca, Cr, Fe, Mg, and Al. High correlation coefficients (r ≥ 0.8) were found for the elements Mg, Ca, Fe, Al, Cd, Pb, and Zn in the PM₁ fraction, Cd, Pb, and Zn in PM_2.5, and Ba, Sb, Fe, Cu, Cr, Mg, Al, and Ca in PM_2.5–10. Using PMF analysis, three major sources of PM (abrasion from tires and brakes, road dust resuspension/winter salting, and combustion processes) were identified for the PM_2.5 and PM₁ fractions, as well as for the coarse PM_2.5–10 fraction. This study reveals the importance of non-exhaust PM emissions in the urban environment.

Urban air quality is continuing to deteriorate. If we want to do something about this problem, we need to know the cause of the pollution. The big problem, not only in Europe, is the high concentrations of particulate matter (PM) in the urban environment. The origin of these particles can be different, including combustion, transport, industry, natural resources, etc. Particulate matter includes a large amount of the finest PM fractions, which can remain in the air for a long time, easily enter respiratory tracks, and damage human health. Particulate matter is also produced by the abrasion of different parts of roads and vehicle fleets and from resuspension road dust, which concerns matter with larger aerodynamic diameters. For this reason, we carried out a series of measurements at various measuring stations in Žilina, Slovakia, during different measuring seasons. The main objective was to find out the diversity of particulate matter sources in Žilina. The search for the particulate matter origin was carried out by particulate matter measurements, determination of the particulate matter fraction concentrations (PM₁₀, PM_2.5, and PM₁), an investigation on the effect of secondary factors on the particulate matter concentrations, chemical analyses, and multivariate statistical analyses. Varied behavior of the particulate matter with respect to the measurement station and the measurement season was found. Differences in the concentrations of investigated chemical elements contained in the PM were found. Significant changes in the concentrations of particulate matter are caused not only by primary sources (e.g., road traffic in the city of Žilina), but mainly by the negative events (combination of air pollution sources and meteorological conditions). Maximum concentrations of particulate matter PM₁₀ were measured during the winter season at the measuring station on Komenského Street: PM₁₀ 126.2 µg/m³, PM_2.5 97.7 µg/m³, and PM₁ 90.4 µg/m³ were obtained using the gravimetric method. The coarse fraction PM_2.5-10 was mainly represented by the chemical elements Mg, Al, Si, Ca, Cr, Fe, and Ba, and the fine fraction PM_2.5 was represented by the chemical elements K, S, Cd, Pb, Ni, and Zn. Road transport as a dominant source of PM₁₀ was identified from all measurements in the city of Žilina by using the multivariate statistical methods of principal component analysis (PCA) and factor analysis (FA).

The authors present the unsolved issue of the contextual design of urban intersections (UI) from the point of view of traffic noise emissions around residential buildings in the Slovak context. Noise barriers are very rarely used in urban areas, due to such reasons as lack of space for their installation, traffic safety (view at intersections), architectural factors, as well as the fact that they represent a barrier for pedestrians and cyclists. The use of low-noise asphalt pavements is limited in urban areas primarily due to the high cost of production and maintenance of these covers, their limited durability in a colder climate, and lower efficiency compared to the roads outside urban areas. From this aspect of urban intersection design, the authors focused on the identification of individual factors associated with the significant reduction (2–8 dB) of traffic noise induced by the reconstruction of non-signalized urban intersections into roundabouts. The authors draw attention to the fact that both new surfaces of intersection branches and the change in traffic processes contribute to the aforementioned reduction. This finding was obtained by comparing direct measurements of noise levels and the results of their predicted values using validated 3D models in the CadnaA program. Noise emissions were measured by a noise analyzer (NOR-1210), and traffic noise emissions were predicted by the “Nouvelle Méthode de Prévision du Bruit” methodology (NMPB-1996). Based on the analysis of the measured and predicted traffic noise levels, the authors objectivized the share of reduction in traffic processes in the 2–3 dB range. The authors objectified the share of traffic noise reduction due to the change in traffic processes as being in the 2.2–3.3 dB range. The presented research results could contribute to a quantifiable reduction in the noise load in the external environment of residential buildings using the contextual design of intersections.

Particulate matter (PM) is present in the surrounding air. The tunnel environment is no exception, where the PM source is road traffic. In a broader sense, the tunnel can be described as a separate point source of air pollution from which PM pollutants spread to the portal parts and the external environment. PM originates from the exhaust and non-exhaust processes of road traffic (brake wear, tire wear, road surface wear, and road dust re-suspension). This study deals with the specification of non-exhaust PM emissions in a tunnel environment where the primary source is road traffic. PM measurements took place in the “Považský Chlmec” highway tunnel with a length of 2,118 m directly in the tunnel tube and near the tunnel portal. PM measurements were performed using gravimetric and optical methods. PM chemical analyses were performed using energy-dispersive X-ray fluorescence (EDXRF). The concentration of PM in the tunnel was on average: PM₁₀ = 30.76 μg/m³ and PM_2.5 = 15.66 μg/m³ and near the tunnel portal PM₁₀ = 14.38 μg/m³ and PM_2.5 = 8.74 μg/m³. The average traffic volume in the tunnel tube was 2,274 veh/24 h. Using EDXRF, the main chemical elements Al, Br, Ca, Cl, Cr, Cu, Fe, K, Mg, Mn, Na, P, Si, S, Ti, and Zn were identified in the PM. Chemical element concentrations in PM₁₀ and PM_2.5 were subjected to factor analysis (FA) and principal component analysis (PCA) to determine the origin of PM. Two sources were identified for PM₁₀ and three for PM_2.5. Absolute principal component scores (APCS) in conjunction with multiple regression analysis (MRA) were used to determine the source contribution to the production of PM₁₀ and PM_2.5.

Complying with strict PM₁₀ and PM_2.5 limit values poses challenges in many European regions, influenced by diverse factors such as natural, regional, and local anthropogenic sources. Urban air pollution, exacerbated by road transport, local industry, and dust resuspension, contrasts with rural areas affected by solid fuel-based local heating and increasing wood burning. This study focuses on village of Sučany, located in Slovakia, analysing PM concentrations during non-heating and heating seasons. The method of analysis relies on the use of the MP101M air quality analyser that utilises beta radiation absorption method. One set of measurements was conducted at five distinct locations during the heating season (18/01/2019 to 28/02/2019) and non-heating season (14/08/2018 to 1/10/2018). Significant differences emerged during the non-heating season with corresponding PM₁₀ averages of 23.0 µg/m³ and PM_2.5 at 19.3 µg/m³. In contrast, the PM₁₀ averaged 53.9 µg/m³ and 52.8 µg/m³ during the heating season. The heating season shows PM_2.5 contributing up to 98% of total PM₁₀. The distribution of PM₁₀ and PM_2.5 pollution and the location of the potential source obtained using polar plots differed during the heating and non-heating seasons. This research underscores the impact of local heating on air quality in a typical Slovak village. The key recommendation for targeted interventions is supporting up-to-date air quality data, education, and financial incentives for citizens in order to implement cleaner and modern heating solutions.