The share of wind power in energy consumption is continuously increasing at the national level as well as global. Many national strategies plan an increase in the installed capacity of wind farms in the future. Accordingly, this paper provides an assessment of spatial suitability for wind farm siting and estimation of wind power potential for the territory of Serbia. The unsuitable areas (75.91% of the territory) are extracted based on sociopolitical, physical, conservation, and pseudo-economic constraints (22 factors). The available land (24.09%) was evaluated applying the multi-criteria decision analysis (MCDA) in the geographical information system (GIS) environment using several criteria (wind speed, elevation, slope, proximity to roads and power lines, distance from urban areas, land cover). After correction with the suitability factor, the estimated technical generation power potential is 97.57 TWh, i.e. 82.93 TWh with 15% included losses. The most prospective areas for the development of wind projects are the north (Bačka region), northeast (Banat region, along the lower Danube river valley), and east of Serbia (mountains region and Negotinska Krajina region).

The long-term exposure to PM2.5 (particulate matter with aerodynamic diameter ≤ 2.5 μm) is the leading global health risk factor. The spatio-temporal variability of annual values of the total PM2.5 concentrations in Serbia is analyzed using the high-resolution (0.01° × 0.01°) gridded data set V4.EU.02 for the period 2001-2016. Population counts and density data were used to calculate the population exposure while the urban land cover data were used to estimate the relations between the size of urban area and the concentration of PM2.5. The mean annual values vary in the range 13.93 μg/m3-28.91 μg/m3. The regional differences exist, but the highest values were obtained for urban environments (> 22.5 μg/m3). Negative trend of annual PM2.5 is present in most of the parts of the Serbian territory, especially in the eastern parts reaching -0.37 μg/m3 per year (p ≤ .05). More than 99% of the territory of Serbia has the mean annual values under the national safe limit established by regulation (25 μm/m3), but comparing to the World Health Organization (WHO) guideline (10 μm/m3), all the territory is above the safe level. In line with the trend of urbanization, there is a clear upward trend in the number of population exposed to the higher concentrations of PM2.5. The share of the population exposed to values higher than 25 μg/m3 increased from 6.65% in 2005 to 11.40% in 2015, while comparing to WHO standard, the total population in Serbia is exposed to the values higher than the safe one. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 47007: Geography of Serbia]

Nighttime lights represent the result of satellite observation of the artificial lighting of human activities on the Earth from space during the night, which provides the excellent opportunity to determine their position, pattern, density, and spatial distribution. Such data have a high detail spatial and temporal resolution, which opens a wide range of possibilities for quantitative and qualitative analysis. In this paper, nighttime lights are used as a highly accurate dataset for indirect tracking of changes in temporal and spatial patterns of population distribution and activity in Serbia. Two indicators were applied-Lighted area and Sum of lights. They are calculated for local government units in Serbia, for 2015 and period 2015-2019. The results of the conducted analysis follow the conclusions of the existing knowledge on population distribution based on the official statistical data. Areas with a high share of lighted areas are dominantly urban and the most populated, while traditionally depopulated areas are with a low share of lighted areas. Sum of lights highlighted the distinction between developed and populated north and depressive and depopulated south of Serbia. General conclusion is that ?dark has fallen in Serbia?, not only in peripheral and rural parts of the country, but in the smaller urban centers as well, and it is steadily spreading toward bigger urban areas. With nighttime lights application, this kind of process in terms of spatial disparities, its scope and dynamics can be easily identified, analyzed, and monitored.

Rural areas have been usually observed through agriculture; however, today, it is broadened with various activities. In Serbia, it has been characterized by unbalanced development, which has led to a declining vitality and depopulation. The main goal of this research is detection of seasonally activated rural areas in Serbia, expressed through the population fluctuation, temporary settlement, or occasional use of residential and economic facilities, and identification of spatial patterns of seasonal use. This research applied an innovative proxy—nighttime lights (NTL)—as a complementary tool to statistical analyses, which are conducted in the GIS environment. The calculation encompassed two seasonality coefficients: one based on the NTL and the second based on statistical data on tourist turnover. The spatial frame applies settlement level and micro level (pixels), while temporal includes monthly values for the period 2015–2019. The obtained results highlight tourist activity as the main cause of seasonal activation of rural areas. The largest seasonal fluctuations were registered in mountain areas and spa resorts. For mountain areas, the highest seasonality is in the winter months (peak—January/February), and lowest is in the summer season. The seasonal character of spa centers indicates the similar trend, generally less pronounced (peak—January), however, with higher seasonality during the summer.