The transportation sector is one of the largest sources of EU’s greenhouse gas emissions. In 2011, transportation represented approximately 25 percent of total EU’s greenhouse gas emissions. Urban mobility accounts for 40% of all CO2 emissions of road transport and up to 70% of other pollutants from transport. As, transportation and mobility play a crucial part both in urban economics and the quality of life, it is of great significance to ensure a low carbon transportation sector, so as to deal with the threat that climate change poses to urban areas. This study examines the factors that affect the production of carbon dioxide (CO2) as well as of air pollutants, in 9 major European cities, aiming to provide a comprehensive overview of the actual knowledge on the atmospheric pollution from public transportation systems. CO2 emissions as well as air pollutants, such as CO, HC, PM, NOx are calculated for the diesel and CNG bus fleets of the European cities under study. Finally the environmental benefits, in terms of CO2 and CO, HC, PM, NOx emissions reductions, from the penetration of different biodiesel blends (from B10 to B100) to the bus fleets are estimated.Peer ReviewedPostprint (author's final draft

The main objective of the presented paper was to evaluate the integrated design strategies applied in refurbishment of the prefabricated residential housing, erected in '70 in the New Belgrade, Serbia, in order to achieve energy savings accompanied with reduction of CO2 emissions and improvement of households’ health and comfort. Conducted study led to the preliminary design of energy refurbishment of the existing building, and its conversion to energy efficient building with minimized loads. Building's dynamic behavior and energy efficiency have been optimized implementing BPS-Building Performance Simulation. Very significant reduction of thermal and cooling loads with the reference to the building's existing status is obtained. Refurbishment encompassed comprehensive optimization of building's envelope structure, natural and mixed ventilation. The implementation of a series of EEI (energy efficiency improvement) measures resulted in significant reduction of buildings energy loads. The investment in energy efficiency retrofitting can improve macroeconomic stability and contribute to the sustainable economic growth. Furthermore, economic analyses were performed for each model, considering present economic situation in Serbia and availability of funds for refurbishment. Presented methodology and results of the performed analyses offer an opportunity to extend their application to other neighborhoods, exploring refurbishment potential results if applied on a greater urban scale.Peer ReviewedPostprint (author’s final draft

The refurbishment of the existing housing stock has a twofold aim: to decrease consumption of fossil fuels and to reduce the CO₂ emissions. The main focus of the presented paper is the evaluation of the integrated design approach applied in scenarios for refurbishment of the prefabricated residential multi-apartment building. The criteria used in searching for the best approach to the renewable energy sources-integrated refurbishment were minimized energy loads, minimized CO₂ emissions and improved indoor environment quality, health and comfort. After in-depth environmental analysis, a series of energy efficiency improvement measures were implemented, as a comprehensive optimization of the building’s envelope structure, natural and mixed ventilation and source energy delivery. The building’s dynamic behaviour and energy efficiency have been analysed and optimized by the building performance simulation and PV panels’ integration for the typical meteorological year of Belgrade, Serbia. Energy refurbishment should be approached in an organized, pragmatic and interdisciplinary way. Hence, the focus should be not only on the latest leading-edge technology, but on the synergy of different practices and principles in order to ensure the path to sustainable development and achieving desired objectives.

Analyzing the Köppen–Geiger climate classification and available climate data for the southern European Mediterranean coast, eight reference geolocations were selected for this analysis: the cities of Valencia, Barcelona, Marseille, Rome, Koper, Split, Athens and Nicosia. The first part of the research applies the climate potential for natural ventilation (CPNV) methodology that evaluates the theoretical availability of natural ventilation (NV) for each city location corresponding to human hygrothermal conditions. The second part of the article evaluates possible cooling energy savings (ES) applying the advanced natural ventilation (ANV) space-cooling strategy. A hypothetical four-story atrium office building model is designed for the building performance simulation (BPS) using mixed-mode (or hybrid-mode) and night-time natural ventilation (NNV) approaches. The objective is to present a comparison overview of possible space cooling ES between chosen geolocations. In the context of the current European Union’s (EU) energy transition (ET) process, the article displays ANV possibilities, as a renewable energy source (RES), in the reduction of building space cooling energy demands (ED) on the electricity grid.

El uso de la vegetación como protección a la radiación solar y de generación de confort térmico en espacios exteriores no es algo nuevo, y se ha venido utilizando a lo largo de la historia, muchas veces haciéndolo de una manera correcta y otras tantas de manera incorrecta, obteniendo resultados que no son siempre los deseados. Estudios sobre el uso y comportamiento de la vegetación se han realizado con anterioridad; a su vez estudios sobre el cañón urbano y su influencia en la cantidad de radiación solar que incide sobre el plano horizontal del mismo y su relación directa con el factor de vista de cielo (de ahora en adelante SVF, por sus siglas en inglés) se han llevado a cabo. Lo que no se ha realizado es un estudio donde se consideren estas variables al mismo tiempo. El objetivo de este estudio es el análisis de cómo la presencia y la ausencia de vegetación, así como el uso de diferentes tipos de vegetación en situaciones morfológicas similares alteran la cantidad de radiación directa que incide sobre la calle y como el uso correcto de la vegetación puede ayudar a corregir lo que la morfología del cañón urbano, ayudando a la creación de un confort térmico. L'ús de la vegetació com a protecció a la radiació solar i com a generadora de benestar tèrmic en espais exteriors no és una cosa nova i s'ha utilitzat al llarg de la història, en moltes ocasions fent-ho d'una manera correcta i d'altres de manera incorrecta, obtenint resultats que no sempre són els desitjats. L'objectiu d'aquest estudi és la quantificació de la incidència de la radiació solar directa sobre el pla horitzontal d'un canó urbà, considerant la relació entre la seva morfologia i la vegetació urbana amb què compta. La metodologia utilitzada consisteix en diverses etapes: primerament, la selecció de les àrees d'estudi (a la ciutat de Barcelona), en segon lloc un aixecament de les espècies arbòries presents, en tercer lloc es van elaborar models tridimensionals per dur a terme simulacions per al anàlisi; com a quarta etapa es van prendre mesures “in situ” per al comparar el resultat de les simulacions, es van analitzar i comparar els resultats, obtenint com a conclusió principal que el factor que té més pes pel que fa a la incidència o no de la radiació solar directa sobre el pla horitzontal del canó urbà, és la seva morfologia (relació d'aspecte (H/W) la qual cosa va de la mà amb el factor de vista de cel, SVF, per les sigles en anglès), sent possible modificar la incidència de radiació mitjançant l'ús correcte de la vegetació urbana. L'originalitat d'aquest estudi, rau en prendre en consideració múltiples factors que afecten la incidència de la radiació directa en el pla horitzontal de qualsevol canó urbà (orientació, relació d'aspecte i SVF) en conjunt amb l'ús de la vegetació urbana. The use of vegetation as a protection against solar radiation and as a generator of thermal comfort in outdoor areas is not something new and it has been used throughout history, many times in the right way and many others in the wrong way, obtaining results that are not always the desired ones. The objective of this study is the quantification of direct solar radiation on the horizontal plane of an urban canyon, taking into account its relation between its morphology and the urban vegetation present in the canyon. The methodology used consists in several stages: firstly, the selection of the areas of study (in the city of Barcelona); secondly, a survey of the tree species present; thirdly, three-dimensional models were made in order to run simulations to analyse; as the fourth stage, on-site measurements are made in order to compare the simulation’s results, obtaining as main conclusion that the factor that has greater weight in regard to the incidence or not of direct solar radiation on the horizontal plane of the urban canyon, is its morphology (aspect ratio (H/W), which goes hand in hand with the sky view factor (SVF)), being possible to modify the incidence of direct radiation through the correct use of urban vegetation. The originality of this study, lies in taking into consideration multiple factors that affect the incidence of direct solar radiation on the horizontal plane of any urban canyon (orientation, ratio aspect and SVF), along with the use of urban vegetation.

Urban morphology defines many characteristics of a city, such as its urban quality, density, and free spaces layout with its vegetation, microclimate, and thermal comfort. All these variables have in common the element of urban space, which is where users develop themselves, making it an element of value. As the city evolves, environmental conditions of the area also change. One example is the urban heat island (UHI) effect. The UHI is defined as the accumulation of heat produced by the urban surfaces emitted to the environment, affecting the urban structure and the thermal comfort of users. As discomfort increases, urban public spaces lose their appeal and may be turned into deserted areas. One of the reasons is the lack of vegetation, particularly arboreal species, which protect these spaces from the solar incidence. In this regard, the questions arise as to how urban morphology affects the incidence of solar radiation in the urban canyon, and how vegetation and its characteristics influence climatic comfort. To develop these concepts, three introductory sections are addressed: the city of Barcelona, Barcelona climate, and urban morphology. Where the main variables are solar radiation, urban canyon, orientation, and the role that vegetation plays as a protection.