Aleksandra Krkoleva Mateska

Sustainable management of indoor and outdoor air quality is essential for protecting public health, enhancing well-being, and supporting resilient urban environments. Low-cost air quality sensors enable continuous, real-time monitoring of key pollutants and, when combined with data analytics, provide scalable and cost-effective insights for smart building operation and environmental decision-making. This pilot study evaluates an indoor–outdoor air quality monitoring system deployed at the Faculty of Electrical Engineering and Information Technologies in Skopje, with a focus on: (i) PM2.5 and PM10 concentrations and their relationship with meteorological conditions and human occupancy; (ii) sensor responsiveness and reliability in an educational setting; and (iii) implications for sustainable building operation. From January to March 2025, two indoor sensors (a classroom and a faculty hall) and two outdoor rooftop sensors continuously measured PM2.5 and PM10 at one-minute intervals. All sensors were calibrated against a reference instrument prior to deployment, while meteorological data were obtained from a nearby station. Time-series analysis, Pearson correlation, and multiple regression were applied. Indoor particulate levels varied strongly with occupancy and ventilation status, whereas outdoor concentrations showed weak to moderate correlations with meteorological variables, particularly atmospheric pressure. Moderate correlations between indoor and outdoor PM suggest partial pollutant infiltration. Overall, this pilot study demonstrates the feasibility of low-cost sensors for long-term monitoring in educational buildings and highlights the need for adaptive, context-aware ventilation strategies to reduce indoor exposure.

This paper presents how customer flexibility can be used in the framework of a Demand Side Management (DSM) program. It focuses on household consumers, and aims to show how slight behavioural changes can lead to optimised use of household appliances and consequently, reduced energy costs. The paper presents a solution that would enable household customers to practice their flexibility. The solution is based on linear optimisation technique (LP) which is used to redistribute the use of domestic appliances throughout the day. The results show that implementation of the proposed solution can lead to reduction of hourly electricity use and reduce the overall electricity costs of the household. The optimised use of appliances reduces the household peak load more than 40% compared to the baseline scenario for all analysed cases. The optimisation implemented on specific households allows for reducing energy costs on average by 30%.

The study delves into the realm of air quality forecasting, employing the LASSO (Least Absolute Shrinkage and Selection Operator) modeling technique for enhanced predictive accuracy. Utilizing a diverse dataset encompassing meteorological parameters, pollutant concentrations, and other relevant factors, the research explores the robustness of LASSO regression in predicting air pollution dynamics. The analysis establishes correlations and identifies key predictors, shedding light on the intricate relationships within the data. The paper contributes valuable insights to the field of air quality prediction, showcasing the efficacy of LASSO modeling in providing accurate and reliable forecasts, thus facilitating proactive measures for pollution mitigation and environmental management. Additionally, the aim of the paper is to investigate whether the COVID-19 pandemic exerted any discernible impact on pollution levels.

Air pollution is one of the most important topics as it can cause various reactions of the organisms, such as mental health disorders, respiratory problems or various cardiovascular despises. Many of the side effects of pollution are caused by particulate matter (PM). Therefore air pollution, especially the concentration of PM is monitored in many European countries. In the past years, Skopje has been one of the top-ranked cities in the world concerning the concentration of PM. This paper investigates the effect of the pandemic with COVID-19 and the restriction measures on air quality. The data collected before the pandemic (May 2018), during the global pandemic (May 2020 and May 2021), and after the period with restriction measures (May 2022) are analyzed. The measurement parameters are collected at the technical campus of the Ss Cyril and Methodius University in Skopje, North Macedonia, in May 2018, May 2020, May 2021, and May 2022. In this research, it can be confirmed that the restriction measures had a significant positive impact on air pollution.

This paper conducts a comprehensive evaluation of the ongoing development of legislation within North Macedonia's electricity sector when compared against the corresponding legal framework of the European Union (EU). Specifically, the initial overview promptly identifies North Macedonia's strategic alignment within the EU's political sphere and emphasizes the imperative need for consistent harmonization of national laws. Moreover, it becomes evident that achieving full EU harmonization in the electricity sector necessitates cooperation and the fulfilment of obligations stipulated in the Energy Community (EnC) Treaty. This treaty holds particular significance for North Macedonia as it stands as the country's legally binding agreement with the EU. Hence, monitoring the consistent fulfilment of the treaty requirements, along with assessing the stance adopted by competent institutions and the perceptions of professionals and the broader public in North Macedonia, portrays an overall image of the nation's readiness and commitment to the reform process in preparation for EU accession. Furthermore, given the dynamic nature of EU energy law evolution, especially amid the current tumultuous state of energy crises, EnC Contracting Parties consistently lag in the transposition and implementation of these laws. This paper delineates the imminent pending obligations that North Macedonia must address within this ongoing process.