"How important is urban air temperature?" by Evyatar Erell


Evyatar Erell—Associate Professor, Ben Gurion University of the Negev

After graduating from the Technion (B. Architecture and Town Planning) in 1986, Evyatar Erell joined the Desert Architecture and Urban Planning group at Ben-Gurion University, where he was employed as an architect in the design of innovative energy-saving buildings. He later studied Geography at Ben Gurion University (M.Sc.) and Architecture at Adelaide University (PhD), and was appointed Associate Professor in 2007. Architecture differs from many other disciplines in that expertise cannot be applied in isolation: Successful designs for the built environment cannot be achieved through focused excellence in any one aspect alone. Prof. Erell’s research over the years reflects this unique characteristic of architecture: it has addressed many facets of energy in the built environment, but with few exceptions has dealt with flows of energy at different scales, and how they affect the spaces we inhabit, both indoors and outside. It has explored glazing systems, daylight control and passive cooling techniques for buildings, as well as the urban microclimate, including an investigation of the effect of buildings on the deposition of dust in a desert city; the development of a computer tool for modeling air temperature in urban street canyons; and studies of pedestrian thermal comfort in hot dry environments. Prof. Erell has co-authored several books, including 'Urban Microclimate: The Design of Spaces between Buildings'. He is a member of several expert committees at the Israel Institute of Standards, and has contributed to drafting national standards for thermal insulation and energy certification of buildings.

More about speaker

It has become almost an article of faith among researchers and the green building movement that a primary objective of applied urban climatology is to mitigate urban heat islands. The topic has attracted extensive research, and policies for urban heat island (UHI) mitigation are promoted all over the world by bodies as diverse as the US Environmental Protection Agency and the EU.

The justification for such policies includes promised benefits such as reduction of energy consumption in buildings; improved outdoor pedestrian thermal comfort; lower excess mortality during summer heat waves; and improved urban air quality through reduced ozone formation. The urgency of implementing the proposed policies is further justified by concerns about the combined effect of UHIs and global warming.

There is in fact overwhelming and irrefutable evidence for correlation between increasing air temperature and several negative outcomes. Yet the talk will demonstrate, through a series of studies on different features of the urban microclimate carried out over a period of several years, that emphasis on air temperature reduction might lead to policies that are at best ineffective and in some cases could even be counter-productive.

It will argue that effective implementation of urban climatology requires that we first define the objectives of the intervention in a meaningful manner: Mitigating UHIs in general, and air temperature modification as such in particular, may not be a useful end in itself. Thermal comfort, energy conservation and good air quality, on the other hand, are worthy objectives – but air temperature is often but one of several factors interacting in complex ways to affect them.

12.00-1.00 PM
COOR 5536