Urban health promotion and thermal stress attenuation with the use of green roofs

ABSTRACT The urbanization process produces significant effects on local microclimate, resulting in heat islands and the worsening of thermal conditions inside housing facilities. The implementation of green roofs arises as an alternative in the improvement of indoor thermal conditions in housings, leading sometimes to energy savings as for air conditioning and promoting better health conditions. The evaluation of thermal stress attenuation was performed by comparing two identical prototype housings, where one has green roof and walls, and the other does not. Thermal stress was evaluated based on the Heat Index, which considers the combined effects of temperature and relative humidity. The green roof system played an important role in the attenuation of thermal stress in housings by improving environmental health conditions and minimizing health related risks. The maximum heat indices recorded in the non-vegetated and vegetated prototypes were 57.5 ° C and 49.2 ° C, respectively. In terms of thermal stress attenuation, the adoption of vegetated (green roof) systems decreases the time of exposure of thermal conditions regarding hazardous and extreme danger conditions from 17.3% to 5.4%.