Positive effects of vegetation: Urban heat island and green roofs

• Published in: Environmental pollution (1987) Vol. 159; no. 8; pp. 2119 - 2126
• Main Authors: Susca, T., Gaffin, S.R., Dell’Osso, G.R.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Kidlington Elsevier Ltd 01.08.2011; Elsevier
• Subjects: Air Pollution - prevention & control; Albedo; Applied sciences; bioactive properties; Biological; Buildings; Buildings. Public works; carbon dioxide; Carbon Dioxide - analysis; Carbon Sequestration; Cities; Climate; Conservation of Natural Resources; construction materials; Convection, turbulence, diffusion. Boundary layer structure and dynamics; Earth, ocean, space; Environmental Monitoring; Environmental Restoration and Remediation - methods; Exact sciences and technology; External envelopes; External geophysics; Facility Design and Construction - methods; Green roof; green roofs; heat island; heat tolerance; Hot Temperature; Meteorology; monitoring; Plant Development; Roof; Roofs; Surface albedo; Surface chemistry; temperature; Thermal resistance; Urban heat island; Urban heat islands; Vegetation; Water Pollution - prevention & control; New York; New York City; United States; North America; America; USA, New York, New York City; Green roof; Surface albedo; Urban heat island; Vegetation; Albedo; Buildings; Effect on climate; Urban area; Roofing; Vegetation effect; Microclimate
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2011.03.007

This paper attempts to evaluate the positive effects of vegetation with a multi-scale approach: an urban and a building scale. Monitoring the urban heat island in four areas of New York City, we have found an average of 2 °C difference of temperatures between the most and the least vegetated areas, ascribable to the substitution of vegetation with man-made building materials. At micro-scale, we have assessed the effect of surface albedo on climate through the use of a climatological model. Then, using the CO 2 equivalents as indicators of the impact on climate, we have compared the surface albedo, and the construction, replacement and use phase of a black, a white and a green roof. By our analyses, we found that both the white and the green roofs are less impactive than the black one; with the thermal resistance, the biological activity of plants and the surface albedo playing a crucial role. ► The local morphology and the scarcity of vegetation in NYC core determines its UHI. ► We introduce the evaluation of the effects of the surface albedo on climate change. ► We use it to compare a black roof with a white and a green one. ► Surface albedo has a crucial role in the evaluation of the environmental loads of the roofs. ► Vegetation has positive effects on both the urban and the building scale. Vegetation has positive effects both on an urban scale, mitigating the urban heat island effect; and on a building scale, where albedo, thermal insulation and biological activity of plants play a crucial role.