No abstract

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 (PM 10 , PM 2.5 , and PM 1 ), 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 PM 10 were measured during the winter season at the measuring station on Komenského Street: PM 10 126.2 µg/m 3 , PM 2.5 97.7 µg/m 3 , and PM 1 90.4 µg/m 3 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 PM 10 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).

Traffic volume depends on several indicators. The most important are the degree of motorization, mobility, and especially the travel time and travel cost factor. The article presents an analysis of the possibility of using mobility surveys and traffic counts to achieve a balance between supply and demand. The frequency of congested traffic and over-capacity volumes are determined. By analyzing the trip information captured in the mobility surveys, we detected the strata causing the highest demand—economically active people with “job” as the purpose of their trip. The study area includes the Kysuce region and the city of Žilina in Slovakia. Three scenarios are processed in the article. Scenario 0 defines the current state, scenario 1 defines the situation with free-of-charge public transport, and scenario 2 represents a targeted modal split where saturation is not exceeded. The aim is to shift passengers to public transport and increase the share of public transport in the modal split. Scenario 2 is also presented in terms of saved emissions as an additional factor of relocating passengers from private to public transport. In terms of fare, we found a small change in the modal split with free-of-charge public transport.

This study provides an assessment of the impact of asphalt mixture composition on the particulate matter (PM) emission from the pavement surface into the atmosphere. Pavement surface abrasion was also analyzed and potential differences among asphalt mixtures were determined by the chemical composition of captured PM. Various types of asphalt mixtures and the influence of their compositions on PM concentrations and chemical composition were studied and compared. The laboratory test setup included 12 different pavement samples. On average, the asphalt mixtures with a combination of melaphyre and dolomite as aggregates exhibited the highest values of PM. Measurements of PM 2.5 and PM 1 in the wheel tracking machine were used to study the impact of asphalt mixture properties on pavement surface abrasion. The dependence between the aggregate used in the tested mixtures and the abraded particulates has been confirmed. The Ca content in aggregates was strongly correlated with the abraded particulates, which was not observed for the Si content. The multidimensional statistical methods used showed the division of markers of the asphalt mixture ABOUT THE AUTHORThe authors work at the University of Zilina (UNIZA), Slovakia. Their research interests are focused on air pollution from road transport, road design and environmental impact assessment, holistic approach to sustainable construction and management of roads, especially their pavements, development of innovative climate-adaptive materials and pavement constructions. The authors collaborated on the international project "Air Tritia -Uniform Approach to the Air Pollution Management System for Functional Urban Areas in Tritia Region", and other. During the project was created an air quality system "AQMS" for functional urban areas of the TRITIA region -Poland, the Czech Republic and Slovakia, and a strategy of sustainable transport of territorial units. The research reported in this paper represents an important area of the particulate matter air pollution, which is a part of the authors´ research on the air pollution sources identification.

Pollution of the air by gases and particulate matter is a problem of everyday life. Particulate matter (PM) is one of the hazardous pollutants causing deterioration of the environment and thus quality of life of the population. Long-term exposure to effects of increased concentrations of gaseous pollutants can also cause deterioration of the environment and human health. Particulate matter and gases production by the road transport is a burning issue, particularly for larger urban areas. Many factors influence the air quality what determines its development and changes. Air pollution monitoring was focused on a possible change in the concentrations of pollutants after the change of the crossroad - three-arm crossroad to the roundabout. The subject of this paper is monitoring particulate matter (PM1, PM2.5, PM10) and gases (nitrogen oxides NO, NO2, NOx) in the vicinity of crossroads in the urban area and an evaluation of fraction ratios PM10, PM2.5 and PM1 with regard to construction of crossroad, meteorological conditions and traffic volume. The roundabout has specific construction and routing traffic, what can influence on production and dispersion of traffic related emissions. The obtained results indicate a decrease in particulate matter concentrations at the roundabout over a three-arm crossroad and an increase in nitrogen oxides concentrations at the roundabout compared to the three-arm crossroad. According to the data obtained and analyzed, the PM10 particulate matter concentrations at the roundabout could be reduced by up to 50% over the three-arm crossroad.