© by PSP Volume 16 – No 10. 2007 Fresenius Environmental Bulletin 1619 BETTER URBAN MICROCLIMATE VIA A PROPOSED CITY PLANNING TOOL. A CASE STUDY IN GREECE Lila Theodoridou-Sotiriou*, Glykeria Kariotou, Eleftherios Panagiotopoulos and George Kariotis Technological Educational Institute of Serres, Department of Geoinformatics and Surveying, Serres, Greece Presented at the 13 th International Symposium on Environmental Pollution and its Impact on Life in the Mediterranean Region (MESAEP), Thessaloniki, Greece, 08 – 12 Oct. 2005 SUMMARY In Greece, the minimum mandatory distance (D) of a building from the plot’s boundaries, relates only to the building’s maximum height (H), given as D = 3 + 0.10*H. This is the main institutional tool that shapes urban open spaces and, consequently, the urban microclimate in Greece. In this paper, we will illustrate a numerical model for city planning, named D (b) in an attempt to define mandatory minimum distance between building structures on differ- ent plots, taking into account the ground relief and climatic conditions of an area. The methodology we used to create the model is based on bibliographical sources for biocli- matic design. In particular, we were interested in identify- ing data regarding the sun’s height angle (V sun), the height of the building causing shading (Z building), the desired shadow height (Z shadow), and the ground slope (ω). Our model was a pilot one applied in the city planning of a sparsely built area (a separate unit) to be incorporated in the master plan of Serres town in Northern Greece. Two city planning scenarios were developed (one using the pres- ently applied, and the other using the proposed tool), and the results of the expected thermal islet, as given by the two scenarios, were evaluated in comparison. The results of this pilot program suggest that biocli- matic distance between building structures [D (b)] contrib- utes to the utilization of passive energy saving systems. Thus, it could be institutionally utilized and, in combination with currently observed distances, could constitute a valu- able addition to the existing city planning tools in Greece. KEYWORDS: Urban microclimate, building coefficient (BC), build- ing heights, cylindrical diagrams of solar height and azimuth, bio- climatic distance between buildings. INTRODUCTION The typical south European city suffers from: a) traffic congestion, atmospheric pollution and noise, b) lack of open public spaces and green spaces, c) high densities, degrada- tion of the urban environment, and d) insufficient arrange- ments for adequate sunning. Numerous E.U. policies al- ready address the climatic change aiming to achieve sus- tainable city planning. A bioclimatic approach to urban planning can reduce adverse effects [1]. Morphological features of the built environment that have a special bearing on urban microclimate are: a) den- sity and building system, b) geometry of urban street can- yons, c) structural materials of buildings, and d) open air spaces. Several variations of these featurescan influence: a) sunning and shading of the external surfaces of build- ings, b) visibility of the celestial dome and, therefore, the lighting and cooling of buildings and open spaces, c) air permeability of the urban tissue and, therefore, the airing and cooling of the city, d) reflectiveness and thermal capac- ity of urban tissue and, therefore, the maximum values and variations of air and surface temperature and e) green content that, among others, influences air temperature [2]. In areas with Mediterranean climate like Greece, sun- ning and solar ray protections are the key objectives for bioclimatic design models [3]. Analytical elements for the specification of the sun’s position are height and azimuth angles for every given moment in time. The use of the “apparent observed path of the sun” constitutes an impor- tant element for bioclimatic design [4]. Given particular geographical latitude and atmospheric conditions, the con- trolling factors of sunning are the geographical orientation and breadth of streets, the choice of width for building poly- gons, and the distance between building structures [5]. Dis- tance between building structures determines the minimum width of building polygons as well as the minimum breadth of streets. An increase in the breadth of streets can occur for functional reasons [6]. Conversely, breadth can be decreased (creation of pedestrian ways) by imposing larger portions of plots as border space between buildings [7].