The influence of roadside green spaces on thermal conditions in the urban environment

Abstract

Urban roads have a particularly negative impact on the urban environment and life in the city. In addition to being a source of various kinds of pollution (noise, dust, soot, etc.), large areas of asphalt cause an increase in the urban heat-island effect. Green spaces in urban areas during the growing season (especially in the summer in warmer climate zones) can mitigate the effect of overheating in cities by shadowing surfaces that absorb heat through evapotranspiration. Depending on the amount of space they cover in the city and their position relative to urban roads, roadside green spaces can play an important role in the improvement of urban microclimatic conditions. The starting assumption of this paper is that roadside green spaces have a positive impact on the air temperature in their immediate environment during the growing season, while the size of that impact depends on the cover, dendrological structure, and area of those green spaces. This research was conducted in five sample roadside green spaces along main roads in New Belgrade, Serbia. The results showed that, during the growing season, roadside green spaces with areas ranging from .7-1.4 ha had a positive impact on air-temperature modification, reducing the air temperature in their immediate environment by 1.8-2.2 degrees F (1.0-1.2 degrees C). The size of the impact depended on the dendrological structure and cover o f the green spaces. The intensity of air-temperature modification was not proportional to the area of the investigated green spaces. The results of this study provide guidelines for the improvement of urban-planning techniques and the establishment and management of this category of open green spaces.