Energy transition in the European Union (EU) is strongly related to public support from structural funds which enable member states to create new and renovate existing renewable energy source (RES) installations. However, in order to maximize benefits of these investments it is crucial to consider where RES funds are allocated, how it corresponds with RES potential in specific locations, and how future implementation of energy policies can be improved. In this study, RES development projects supported by EU funds, implemented in the period 2004–2019 in Poland, were analyzed in relation to solar, wind and biomass energy potential. The study was conducted with the use of agglomeration method and k-mean method to define clusters of local administrative units characterized by similar features of RES funds absorption and renewable energy production potential. The results obtained show that in the case of all energy sources there is no correlation between high RES funds absorption and energy production potential. The final conclusion of the research is that in order to boost energy transformation into more sustainable solutions, renewable energy production potential should be considered as a factor to allocate public financial support for future energy policy implementation.

The aim of this study was to determine the change of water quality in the Trzemna River after modernisation of the wastewater treatment plant (WWTP) in Gołuchów and wastewater effluent diversion (WED) to the Prosna River in 2008. Data was acquired from the State Environmental Monitoring database for the period before and after changing the location of discharge from the treatment plant. The before-after (BA) and before-after-control-impact (BACI) analyses were used to determine the effectiveness of applied solutions. The BA study covered 12 physicochemical parameters and showed improvement of water quality in terms of phosphorous compounds, EC, ammonium nitrogen, TKN, TN, and BOD5. Lack of statistically significant differences for nitrates, pH, and TOC were noted. The BACI analysis was only applicable for six physicochemical parameters, and statistically significant differences were shown for TN, TKN, ammonium nitrogen, and TP. There were no differences in the case of nitrates and DO. After wastewater effluent diversion, a high concentration of nitrates in Trzemna water was still observed, with a statistically confirmed increasing trend. This is an effect of the negative impact of agricultural diffuse pollution. Modernisation of a WWTP and wastewater effluent diversion positively affected the quality of Trzemna water. The BA and BACI analyses in relation to statistical tests applied in hydrology can be successfully used to evaluate the impact of changes in the environment on water quality. In the case of BA design it was possible to analyse 12 parameters, whereas in BACI analysis it was only half of them. However, this method is recognised as more reliable and eliminates the impact of natural temporary variations.

Studying the air quality and exposure of the inhabitants of urban agglomerations to pollution is the basis for the creation and development of more sustainable cities. Although research on black carbon (BC) has not yet reached the official acceptable levels and guidelines, the World Health Organization clearly indicates the need to measure and control the level of this pollutant. In Poland, monitoring of the level of BC concentration is not included in the air quality monitoring network. To estimate the extent of this pollutant to which pedestrians and cyclists are exposed, mobile measurements were carried out on over 26 km of bicycle paths in Wrocław. The obtained results indicate the influence of urban greenery next to the bicycle path (especially if the cyclist is separated from the street lane by hedges or other tall plants) and the 'breathability' (i.e., associated with surrounding infrastructure) of the area on the obtained concentrations; the average concentration of BC in such places ranged from 1.3 to 2.2 μg/m³, whereas a cyclist riding directly on bike paths adjacent to the main roads in the city center is exposed to concentrations in the range of 2.3-14 μg/m³. The results of the measurements, also related to stationary measurements made at a selected point of one of the routes, clearly indicate the importance of the infrastructure surrounding the bicycle paths, their location, and the impact of urban traffic on the obtained BC concentrations. The results presented in our study are based only on short-term-field campaigns preliminary studies. To determine the quantitative impact of the characteristics of the bicycle route on the concentration of pollutants, and thus the exposure of users, the systematized research should cover a greater part of the city and be representative in terms of various hours of the day.