Abstract
The Urban Heat Island phenomenon and urban overheating are serious consequences of urbanization resulting in impacts on thermal comfort levels, heat stress and even mortality. This paper builds on previous findings on the topic of non-constructible parcels, small vacant or built spaces in Municipal Beirut, some of which belong to the municipality while others are privately owned and which might be used for different functional purposes. This paper further examines the possibility of implementing cool surface or paving materials and urban vegetation to reduce air urban temperature, especially during the summer period and with the view to project the positive findings of this case study to the entire Municipal Beirut area. A numerical analysis using ENVI-met 4.0 investigates the thermal performance of these non-constructibles further to implementation of high reflective surfaces and urban vegetation on a broad neighborhood scale, taking the Bachoura District as a reference case for a typical summer day. The best air temperature reductions correspond to the use of cool material in areas that are far from buildings where there are no shadow effects. In some cases, the introduction of trees leads to an increase of the air temperature near the ground because they became an obstacle of the natural ventilation. Results show a maximum mitigation effect with the use of cool materials that lead to reductions in air temperatures up to 0.42 °C if used alone and up to 0.77 °C if used in combination with trees. Within the framework of an integrated approach to planning, this form of urban intervention aims for substantial overheating reduction.
Highlights
Today, 54% of the world’s population lives in urban areas, a proportion that is expected to increase to 66% by 2050 [1]
The major master plans for Beirut were subject to several updates throughout their history, such as the Danger Brothers Scheme in 1932 and the Ecochard schemes in 1943 and 1964, and combined with an outdated laws and regulations system that manages urban operations, have enriched the urban fabric of Municipal Beirut with a non-negligible number of non-constructible parcels (NCs) [45]
The objective of this paper is to explore the potential of NCs to reduce urban air temperatures through the case study of the Bachoura District, preparing grounds for future implementation projects on selected NCs throughout Municipal Beirut at a larger scale
Summary
54% of the world’s population lives in urban areas, a proportion that is expected to increase to 66% by 2050 [1]. Vegetation has been studied in urban climates [19] in order to reduce the urban heat island effect This type of mitigation technique cools the environment through a higher albedo In 2008 [29] carried out a numerical study on large areas of Athens, Greece, in order to simulate the impacts of cool materials on the urban heat island effect. The major master plans for Beirut were subject to several updates throughout their history, such as the Danger Brothers Scheme in 1932 and the Ecochard schemes in 1943 and 1964, and combined with an outdated laws and regulations system that manages urban operations, have enriched the urban fabric of Municipal Beirut with a non-negligible number of non-constructible parcels (NCs) [45] These are leftover spaces found in the shape of small vacant or built spaces in between buildings or around corners and belonging to the municipality, which might be used for social purposes.
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