Beata Górka-Kostrubiec

Dependence of air pollution on meteorological conditions based on magnetic susceptibility measurements: a case study from Warsaw

This study reports systematic analysis of air pollution concentration by particulate matter (PM) in relation to annual changes of metrological conditions. The concentration of PM collected on filters was evaluated by magnetic properties. Long series of filters collected during 1977, 1980, 1981 and 1985 in Warsaw have been used for measurement. Such long time series allowed a better determination of correlation between seasonal susceptibility changes and meteorological conditions and to verify the repeatability of annual behavior. The magnetic susceptibility normalized by mass (χ) has been used as a proxy of pollution. Monthly variations of χ (χm) demonstrated slow and small seasonal changes disturbed by quick, high peaks. The filters with high susceptibilities contain a mixture of magnetic single and multidomain grains which is characteristic for anthropogenic pollution, with the frequency-dependent susceptibility χfd being less than 4%. The low susceptibility samples are characterized by admixture of small amount of pseudo-single domain (PSD) and possible small amount of superparamagnetic (SP) grains. Detailed analysis of reduced mean monthly susceptibility χR revealed that temperature and absolute humidity correlate positively in cold period of year and negatively in warm months. The linear correlation coefficients range from 0.7 to 0.9 and from 0.3 to 0.4 for negative and positive linear correlation, respectively. The dispersion of pollutants in a city depends on the way of ventilation. The big cities like Warsaw are urban heat islands which act the most effective way for the warm period and for the cold time. The correlation of χR with absolute humidity is similar to that for temperature but for different reasons. The presence of big amount of water vapor particles in the atmosphere can favor the adhesion of smaller ferromagnetic grains to their surface which can accelerate the process of falling down of such agglomerates. Such a process can take place during wintertime. We do not observe clear correlation between χR and precipitation.

Magnetic signature of indoor air pollution: Household dust study

The combination of magnetic and geochemical methods was used to determine the mineralogy, grain size and domain structure of magnetic particles in indoor dust collected in 195 sites in Warsaw, Poland. Data show an asymmetric distribution of magnetic susceptibility (χ) in the wide range of 20–1514 × 10−8 m3 kg−1. Comparison of magnetic parameters shows that the internal dust contains outside pollution characteristic for air and soil. More than 90% of indoor dust samples were characterized by roughly uniform magnetic mineralogy, typical for fine grained magnetite (diameter of 0.2–5 μm), and grain size between pseudo-single-domain and small multi-domain with small contribution of superpara-magnetic particles (∼10%). Samples with χ larger than 220 × 10−8 m3 kg−1 contain mainly magnetite and an anthropogenic metallic Fe with TC > 700°C. The indoor dust contains, characteristic for the urban areas, spherical magnetic particles originated from fossil fuel combustion processes and mixture of irregular angular iron-oxides grains containing other elements, including Na, Ca, Al, Si, K, S, Mn, Cl, and Mg.

Magnetic particles in indoor dust as marker of pollution emitted by different outside sources

The potential relation between outdoor pollutants and the quality of indoor air was evaluated. A case study was carried out in the small town of Zyrardow situated south-west of Warsaw, Poland. The indoor dust from 20 apartments from several parts of the town that are anticipated to be exposed to various levels of pollution was investigated: a mildly polluted area (suburban), a heating plant area, a post-industrial area and the city center. For evaluation of indoor dust several magnetic parameters (mass-specific magnetic susceptibility χ, its temperature dependence, anhysteretic remanent magnetization, hysteresis loop parameters) were applied. Analysis of magnetic properties was supplemented by analysis of chemical elements: Cd, Cu, Co, Cr, Fe, Mn, Ni, Pb and Zn. Depending on the location of apartments, large variations in concentration, mineralogy and grain-size of magnetic particles were detected. The thermomagnetic analysis revealed magnetite as a primary magnetic phase. In indoor dust, the Curie temperature of ~760°C and soft hysteresis loops with relatively low coercivity values of ~1.5-5 mT are an attribute of metallic iron. The dust collected from apartments located near the local heating plant area, in contaminated post-industrial and suburban areas contains mainly magnetite and only a small amount of metallic iron. Mass-specific magnetic susceptibility is in the range from 40 to 200 × 10-8 m3kg-1 and linearly correlates with concentration of individual heavy metals: Ni, Cr, Co and Zn. Magnetic fraction of dust from the city center mainly consists of magnetite and variable amounts of metallic iron. Magnetic susceptibility shows linear correlations with concentration of Fe and concentration of individual heavy metals (Zn, Ni and Co) considered as traffic-related. The study demonstrates that metallic iron present in indoor dust is a potential marker of trafficrelated sources and it makes it possible to use magnetic methods as a tool for evaluation of traffic-related impact on indoor air levels.

Magnetic Vertical Structure of Soil as a Result of Transformation of Iron Oxides During Pedogenesis. The Case Study of Soil Profiles from Slovakia and Ukraine

This work reports the study of depth differentiation of magnetic properties of four soil types: Kastanozem, Cambisol, Luvisol and Chernozem. The aim of the study is to find the way of magnetic minerals formation and transformation. The three profiles: Cambisol, Luvisol and Chernozem were taken from moderate temperature and moisture region from Slovak Republic and one profile, Kastanozem, was taken from semi-dry region of Southern Ukraine. Thermal behavior of saturation remanence revealed that magnetic composition of studied soils is a mixture of two components. Upper layers contain significant contribution of maghemite. This is demonstrated by unblocking temperature Tub lower than 670 °C and higher than 600 °C and low values of coercivity Bc and Bcr. Variable amounts of hematite demonstrated by Tub ~ 670 °C are seen for samples from parent rock horizons. Cumulative log Gaussian (CLG) analysis of the IRM acquisition curve revealed the presence of at least two components of coercivity along each profile. The variation of hematite content along profile was evaluated by depth variation of hard component of saturation remanence HIRM. The domain state of magnetic minerals derived from the Day’s plot modified by Dunlop showed that all samples are grouped in the area between the mixing curve for single-domain SD and multi-domain MD grains and the mixing curve for SD and superparamagnetic SP grain. The depth variation of susceptibility χ, frequency dependence of susceptibility χfd, hysteresis parameters, anhysteretic remanence ARM, hard component of isothermal remanence HIRM, and relations between these magnetic parameters were used as indicators of development of pedogenesis. The results allow us to conclude that formation of iron oxides occurred by a transient intermediate phase—hydromaghemite which was transformed to hematite and/or to goethite depending on soil environment. The ratio χfd/HIRM allows to evaluate approximately similar precipitation for Kastanozem, Cambisol and Luvisol and much lower for Chernozem. As Chernozem should be formed in the same conditions as Cambisol and Luvisol, we probably observed the effect of higher permeability of parent rock in Chernozem profile sediments than in the case of Cambisol (granite) and Luvisol and Kastanozem (loess). Relation of loss on ignition LOI to magnetic parameters indicates that organic matter promotes pedogenesis progress. It is possible to relate vertical magnetic structure of soil to pedogenic differentiation into genetic horizons.

Magnetic Study of Sediments from the Vistula River in Warsaw—Preliminary Results

The aim of the study was to identify magnetic particles in the sediments of Warsaw part of the Vistula river (Poland) and the impact of anthropogenic factors on the magnetic susceptibility. One of the most important parts of this study was to determine the procedure for sediment sampling and preparation of material for magnetic measurements. The paper presents results of the preliminary study on the test collection of sediment samples from the Vistula river bank within Warsaw. The main magnetic study was carried out on the collection of sediments taken from six areas with different impact of anthropogenic sources of pollution using the procedure developed for test collection. For samples of sediments, several magnetic parameters, such as magnetic susceptibility χ, temperature dependent magnetic susceptibility, and hysteresis loop parameters, were determined. The study showed that the magnetic susceptibility of sediments reflects the anthropogenic impact. In the city center, the magnetic susceptibility reached maximum values which reflect the highest anthropogenic factor. The lowest magnetic susceptibility values were recorded in sediments taken from out of the city center areas which shows relatively low impact of anthropogenic factor. The fine-grained fractions of sediments contain most of the magnetic particles in which multidomain magnetite is the main magnetic phase. It was found that the spherical-shaped particles represent a significant part of magnetic fraction of sediment. The results bring us to the conclusion that the application of magnetic methods for study of river sediments is very important for understanding and tracing the anthropogenic input in the river sediments.