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2 2013

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Wpływ emisji komunikacyjnej na stężenie dwóch form węgla i rozkład ich masy względem wielkości cząstek w aerozolu atmosferycznym obszaru miejskiego

Rogula-Kozłowska W., Rogula-Kopiec P., Klejnowski K., Błaszczyk J.

Rocznik Ochrona Środowiska

2013

Tom 15, cz. 2

1623--1644

Ambient particulate matter (PM) is a component of the natural environment and a certain number of particles that varies with time, having many different properties which also change over time, is constantly present in the air. It can be assumed that the scope of environmental effects of PM is the broadest among all air pollutants: it affects the human health, climate, ecological conditions and visibility. Organic carbon (OC) and elemental carbon (EC) are the two most important components of suspended dust. The continuously increasing road traffic intensity is highly correlated with increasing concentrations of both of these components in the air of urbanized areas all over the world. In spite of this, the amount of data on OC and EC concentrations in Poland is still insufficient, especially in the case of areas located close to busy roads. The aim of this study was to determine the influence of vehicular traffic on ambient concentrations of PM-related OC and EC, and their mass size distribution in a typical urban area of the Upper Silesia. PM samples were collected simultaneously at two sites located in the Katowice city. One of the selected measurement points was situated in the city centre and characterized so-called urban background. The second measurement point, located near the A4 motorway, was in the area directly exposed to the influence of traffic emission. Dust was sampled during two measurement periods (2–10 August and 15–22 September 2011) using thirteen-stage impactors – DEKATI Ltd. (DLPI, Dekati Low Pressure Impactor). Analysis for the content of OC and EC in the collected dust samples was carried out by means of a thermo-optical method with the use of a Sunset Laboratory OC/EC carbon analyzer. During the entire measurement program strict adherence to the rigorous requirements for quality control of the obtained results was ensured. Concentrations of PM1-, PM2.5- and PM10-related OC and EC in Katowice, near the A4 motorway, were close to values obtained in other parts of the world in different measurement periods, at traffic sites of similar characteristics. Also values of the concentration ratio of OC bound to PM10 and PM2,5 (or PM2,5) were similar to quantities determined in different locations. In Katowice, due to municipal emission and poor quality of vehicles travelling the roads, also the coarse fraction of dust was enriched in EC. This situation is unusual in comparison to other regions. The effect of emission from engines of the cars travelling the motorway manifested itself mainly by elevated EC concentrations compared to the urban background site. For TSP the EC concentration was higher, five times in the beginning of August and two times in the second half of September. The largest differences between EC concentrations in the location near the motorway and in the urban background area were observed for the PM0.06–0.108, PM0.108–0.17 and PM0.17–0.26 fractions. In both measurement periods, at the traffic site in Katowice, the maxima of mass size distribution of EC were in the diameter range characteristic for soot emitted from Diesel engines (0.108–0.26µm). The fact that the influence of exhaust emission from vehicles travelling the motorway on EC concentrations was more pronounced in the second half of September than in the first half of August, was caused by larger EC emission from various sources in Katowice during the period following summer holidays. Concentrations of organic carbon bound to TSP in both measurement periods in Katowice was only 10% higher in the urban traffic site than in the urban background site. The largest differences between OC concentrations near the motorway and in the urban background are observed in the ranges 0.06–0.17 and 1.0–2.5 µm. Maxima of the mass size distribution of PM-related OC, both at the urban traffic site and at the background site, were similar in both measurement periods. It was inferred that the small differences between OC concentrations in the traffic and the background site are caused by the process of secondary aerosol formation, less intensive near the motorway than in the urban site.

Masowy rozkład pierwiastków w próbkach pyłu zawieszonego pobranych w obszarze tła miejskiego: wyniki ośmiomiesięcznych badań w Zabrzu

Rogula-Kozłowska W., Klejnowski K., Rogula-Kopiec P., Błaszczak B., Mathews B., Szopa S.

Rocznik Ochrona Środowiska

2013

Tom 15, cz. 2

1022--1040

The analysis of elemental composition of ambient dust can help not only evaluate the environmental and health effects due to the air pollution but also identify emission sources. However, the whole number of projects and studies on concentrations and elemental composition of ambient (especially fine) dust hardly concern these issues in Eastern Europe. Neither is the chemical (and elemental) composition of the submicron ambient dust in Poland well recognized. There is also a shortage of data from long-term and parallel studies of the elemental composition of separate dust fractions. In the heavily polluted areas, the elemental composition of atmospheric aerosol and the dependence of elemental composition of particles on their size can appear essential for analyzing the toxicity of dust and its environmental effects. This study presents the results of determination and comparison of the elemental composition of four fractions of ambient dust in Zabrze (Poland), an urban area typical of the exposure of the Upper-Silesian Agglomeration population to the polluted air. The samples of the four dust fractions (fine: ≤1 µm – PM1, 1–2.5 µm – PM1-2.5, coarse: 2.5–10 µm – PM2.5-10, and 10–40 µm – PM10-40,) were collected during eight months (January–August 2009) with the use of a DEKATI-PM10 cascade impactor. All the dust samples (204 samples) were analyzed using a PANalytical Epsilon 5 spectrometer (EDXRF – energy dispersive X-Ray fluorescence spectroscopy). The minimum, maximum and average concentrations, for winter (January–April, heating season) and summer (May–August, non-heating season), of 38 elements from each of the four examined dust fractions were calculated. The influence of anthropogenic sources on the ambient concentrations of elements from each dust fraction was determined by analyzing the enrichment factors (EF). The strength of linear relationships (Pearson’s linear correlation coefficients) between each pair of elements was determined separately for fine and coarse dust. The highest ambient concentrations were assumed by two nonmetals – sulfur and chlorine; their concentrations were significantly lower in summer than in winter. Both sulfur and chlorine were mainly bound onto the finest particles. Their share in the coarse dust, even in summer, was small. They came from anthropogenic sources. Ambient, typical crustal, Si, Al, Fe, Mg, K, Ca, Ti, Sr, Rb in Zabrze came from natural sources regardless of the fraction they were bound to. Small seasonal variations in ambient concentrations of these elements or some of the concentrations higher in summer than in winter confirmed the fact. A significant portion of the mass of the crustal elements, especially of Al, Si and Fe, was concentrated in the coarse fractions. However, the mass distribution among the dust fractions indicates some of them (K, Ca, Mg, Rb, Sr) as coming partly from anthropogenic sources. It particularly concerns their part bound to fine dust in winter. The mass contribution of crustal matter to ambient dust was about 6.8 in winter and 9.7% in summer; the contribution to PM1 was half of it. Almost all remaining 27 elements (except for Mn, Zn, Ge, Sb, La) had the ambient concentrations not greater than 100 ng m-3, usually higher in winter. The average mass shares of each of these 27 elements in PM1, PM1-2.5, PM2.5-10, and PM10-40, were different and depended on the season of a year. Co, Cu, Zn, Pb and As were cumulated mostly in fine dust, while V, Mn, Co, Cr, Ni, Ag, Cd and Ba in coarse dust. The former, in fine dust, were assumed to be rather of anthropogenic origin and closely associated with combustion. The later originated partly from combustion (especially in winter) but their greater part was secondary and came from road dust. The largest contributors to the mass of the elements in fine dust in Zabrze are domestic furnaces and car engines, i.e. combustion of fossil fuels, biomass, and waste. The possible effect of industrial sources was also identified. The elemental composition of coarse dust is due to re-suspension of soil and road dust, and to a lesser extent, to municipal emission.