APPLICATION OF LOW-COST OPTICAL PM SENSOR FOR MONITORING OF PARTICULATE MATTER AIR POLLUTION IN THE URBAN ENVIRONMENT: A CASE STUDY IN ESPLANĀDE HOUSING ESTATE, DAUGAVPILS CITY

The harmful health effects of airborne particulate matter (PM) pollutants are well-known. However, the spatial coverage of automated air quality observation stations of Latvian Environment, Geology and Meteorology Centre (LEGMC) is sparse. Therefore the capability for PM concentration detection was examined by using the low-cost optical PM sensor to improve the spatial resolution of environmental data. The aim of the study was to perform 24h/7d measurements of PM2.5 and PM10 concentrations during a period of one year and to identify air quality in Esplanāde housing estate, Daugavpils city. For data obtaining on the concentration of PM2.5 and PM10 particles measurements have been performed by optical sensor Nova SDS011; meteorological data were obtained using the database of LEGMC; for processing, analysis and visualization of obtained data statistical methods were applied. Evaluation of PM2.5 and PM10 daily average concentration variability in 2020 indicates that air quality in the urban environment could be assessed as good. A well-expressed statistical correlation between meteorological factors (t°C, relative humidity) and the average concentration of PM particles was not found. It highlights the necessity of further research

Soil erosion risk assessment at small catchments scale: comparison of GIS-based modelling and field survey data and its implication for environmental maintenance of rivers

One of the limitations to implementation of effective measures to mitigate negative environmental and economic effects associated with soil erosion is the lack of data on the geographic distribution of erosion risk and potential erosion hotspots. Hence, experts and policy makers in many cases have no spatially referenced information on which to base their decisions. There is a trend approved by EU institutions and agencies to use soil erosion models which can be integrated into geographic information systems (GIS) environment in order to obtain data at different spatial scales and to assist such decision-making. Despite that, until now in Latvia only some studies on the GIS-based modelling of potential soil losses have been conducted. Considering that, in the study presented in this paper soil erosion risk assessment has been performed by the widely used Revised Universal Soil Loss Equation (RUSLE) model over five selected small catchments of the river Daugava valley. In order to validate the results of modelling and to assess if theory accords with a real situation, the theoretical data were compared with information gained from the field survey of the same catchments. Modelled potential soil loss from each of five catchments under study totals 0.25; 0.26; 0.42; 0.51 and 0.58 t ha-1 y-1 in average. However, results of the comparison indicate the discrepancies between modelled and measured values, i.e. the used empirical model underestimates the soil erosion risk. The recognition of this fact raises implication for appropriate environmental maintenance of rivers, due to possible underestimation of eroded material delivery to receiving streams and, subsequently, under-prediction of water pollution

ASSESSMENT OF GEODIVERSITY AS TOOL FOR ENVIRONMENTAL MANAGEMENT OF PROTECTED NATURE AREAS IN SOUTH-EASTERN LATVIA

The environmental management and nature protection policy in Latvia is mainly focused on biodiversity and protected species, while a geodiversity is ‘forgotten side’ of nature conservation work. Such situation is associated with an absence of a unified methodology for assessment of geodiversity, which is a shortened version of the term ‘geological and geomorphological diversity’. The concept of geodiversity, as well the quantitative assessment of abiotic nature values is successfully used in the last decade. However, it has not yet been applied in Latvia for purposes of environmental management. Considering that the aim of this study was to apply the methodology described in the scientific literature for the assessment of geodiversity index in the GIS environment. The estimating of geodiversity was performed in two protected nature areas in south-eastern Latvia, i.e. nature reserve “Pilskalnes Siguldiņa” and geological nature monument “Adamovas krauja”. The calculations of geodiversity index were done based on the components as geological data, landform units, morphogenetic processes, hydrological features and terrain roughness. The input data were processed, and numerical methods that analyze spatial data in regular grid format were applied in ArcGIS. The output data on the spatial variability of geodiversity index were reclassified in three classes in order to identify areas with low, medium and high geodiversity respectively. The assessment of geodiversity by quantifying the spatial distribution of geodiversity index can be used as a tool for environmental management of protected nature areas and spatial planning, allowing to identify places with high potential value and to prevent their transformations

Application Of Geographic Information Systems (Gis) In Analysis Of Geological Risk Factors And Assessment Of Geohazards In Daugavpils And Ilūkste Districts

This article deals with the main aspects of geological and geomorphological hazards (geohazards) assessment by presenting review of GIS-based methodology for identification and analysis of environmental hazards of such type to which the Daugavpils and Ilūkste districts are exposed. It includes (1) critical review of the availability and state of the art in data sources about geological risk factors, (2) a description of using geomatics methods for obtaining thematic layers of risk factors and techniques of their combining and overlaying, and (3) an analysis and assessment of summary geohazard risk. Such a complex GIS-based studying of geohazards has not been performed before in the territory under study, nor has it been attempted in Latvia. At the same time obtained results allow highlighting areas exposed to geological risk within the Daugavpils and Ilūkste districts, hence providing relevant information for spatial planning of these territories

Geographic Distribution Of Protected Sedge Species Carex Pilosa Scop. In Latvia With Reference To Forest Ecosystems

The results of field studies, laboratory research and desk-based GIS geospatial analysis of ecological factors which determine geographic distribution of hairy sedge (Carex Pilosa Scop.) in Latvia with reference to forest ecosystems are presented in this article. Hitherto such a complex studying of chorology and ecology of this protected forest herb has not been performed before in Latvia, nor has it been attempted in the other Baltic states. The obtained results demonstrate that this protected plant species ecologically is quite plastic regarding its growing conditions and can be found in different forest ecosystems, however the most vital and largest cenopopulations of Carex pilosa are associated with the old deciduous forests, particularly those growing within erosion landforms on the slopes of the southern or south-eastern aspect. This research is important both from the scientific and practical view point, allowing to work out recommendations for the protection and conservation of this rare species in Latvia

USING OF AIRBORNE LIDAR ALTIMETRY AND SEMI-AUTOMATED GIS TOOLS FOR IDENTIFICATION AND MAPPING OF FLUVIAL TERRACES IN THE AUGŠDAUGAVA SPILLWAY VALLEY

River terraces are one of the typical and widespread Quaternary fluvial landforms in Latvia. Until recently, distinguishing and mapping of these features have required extensive field surveys. However, the availability of high resolution digital elevation models (DEM) derived from airborne laser altimetry and application of modern geographic information systems (GIS) provides sufficient background to resolve these tasks. In this study, we apply an integrated methodology based on using of remote sensing, i.e. laser scanning or Light Detection and Ranging (LiDAR) data and combining of semi-automated TerEx tools for the detection of fluvial terraces in DEM. The empirical tests performed using the tools in the study area reveal that the application of TerEx gives the reliable results. However, presence of minor landforms which increase the topographical roughness of the surface directly influence the quality of extracted data, thus leading to the necessity of additional manual editing. The obtained data indicate that the terrace sequence in the Augšdaugava spillway valley consists of eight different terrace levels – T1 to T8. Only terraces T1 and T2 are easily recognizable in the study area, whereas the upper terraces do not have explicit edges

A geomorphological approach for enhancing environmental management and conservation of landforms as protected nature objects in the Upper Daugava spillway valley

This paper describes the application of geomorphological approach for environmental management and conservation of landforms. Specifically, we discuss the contribution of geomorphological field survey and adapted matrix methodology (in combination with understanding of geology) to identification, study and evaluation of those abiotic nature elements which represent geological and geomorphological heritage. We describe a case study carried out in that part of the protected landscape area “Augšdaugava” which encompasses the Upper Daugava spillway valley. The study programme reported in this paper was realized to perform inventory of landforms and geological features for recognition of objects of particular interest in terms of including them in the list of protected nature monuments. After the field reconnaissance and survey of such objects in situ, the assessment based on several criteria like scientific, aesthetic and paleogeographic value, type, rareness, integrity and representativeness was performed. Obtained data is sufficient to make a well-founded selection of the abiotic nature elements and components of geodiversity, including geological and geomorphological features, e.g. particular landforms as protected nature objects, and to substantiate the need for their conservation. Hence, the output of performed study can be used for enhancing environmental management and conservation of nature diversity and values in this region

SPECTRAL IMAGING AND CLAY DETECTION IN LATGALE LAKES

The survey of lake sediments is complex, time consuming and costly process with risks to human health. Additionally, manually obtained sediment samples provide incomplete data about a survey region. In turn, remote sensing methods are cost-effective and can provide continuous data about a survey region. Therefore, authors decided to perform a pilot experiment with a remote sensing method in order to detect clay sediments deposited in lakebeds. The evaluated method is the analysis of spectral images of Sentinel-2. Pearson coefficient and C4.5 datamining methods were applied for data analysis. Survey objects are Latgale lakes with and without clay sediments. The pilot experiment showed, that spectral imaging of lake water is not applicable method to detect definitely clay sediments in lakes, however, research results provide ideas about indirect methods, which must be studied in the future