Environmental benefits of green roofs on microclimate of Tehran with specific focus on air temperature, humidity and CO2 content

The main objective of this study is to evaluate the genuine effect of green roofs on Tehran's microclimatic conditions and air quality parameters. Two buildings with different roof covers (green and bitumen roof) were selected and air temperature, relative humidity and carbon dioxide concentration data loggers were installed on both of them in two different conditions. Also, the effect of roofs materials on indoor air temperature, heat exchange and energy consumption of each building was assessed by installing internal thermometer inside the rooms to study the indoor thermal conditions of the buildings. Results demonstrated that average air temperature above the green roof was 3.06 and 3.7 °C cooler than that of reference roof inside and outside the screen box, respectively. Also, RH above the green roof was 11.94 and 8.46% higher than the reference roof inside and outside the screen box, respectively. Furthermore, the average air CO2 concentration inside and outside of the screen box above the green roof during the studied period was 27.98 and 20.71 ppm lower than the reference roof. Similarity, interior spaces of the buildings with green roof showed lower measured air temperature than buildings with bitumen roof.