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Summer in the city

ASU experts in a variety of disciplines working on creating solutions and mitigation strategies for extreme heat dangers

Arizona sun

May 23, 2019

The unseasonably temperate weather in the Phoenix metropolitan area this spring may have everyone scratching their heads, but rest assured, heat will always be a concern in the Valley whose name pays homage to the most omnipresent force there – the sun.

“I think it’s a blip,” said Mikhail Chester, associate professor in the School of Sustainable Engineering and the Built Environment at Arizona State University. “I think when you look at the end of the year, in January of 2020, the overall trend for 2019 will fit with what we’ve been seeing everywhere, which is that the average temperature has gone up.”

Chester is one of many researchers at ASU whose work focuses on heat. From mitigating its effects through the built environment to understanding how socioeconomic status factors into heat-related vulnerabilities, their lines of inquiry run the investigative gamut.

In recognition of Arizona Heat Awareness Week May 27 through May 31Starting on Memorial Day, May 27, the Arizona Department of Health Services and the National Weather Service Offices in Arizona will be coordinating a 2019 Arizona Heat Awareness Week Campaign. During the five-day campaign, a variety of messaging will be disseminated daily to help remind residents and visitors about ways to stay safe in the heat., ASU Now is highlighting a slew of projects and initiatives that are expanding our understanding and capabilities as they concern the inescapable environmental reality of scorching temperatures.


Mikhail Chester

Associate professor in the School of Sustainable Engineering and the Built Environment

Chester serves as a co-leader of ASU’s Urban Resilience to Extremes Sustainability Research Network, also known as UREx SRN. The research network includes 17 partner institutions in nine cities across North and South America. Supported by a $12 million grant from the National Science Foundation, UREx SRN aims to devise, analyze and support urban infrastructure in the face of climatic uncertainty and put cities on paths to sustainable futures.

One of the projects to come out of the network is the ICARUS project, which uses simulation modeling to look at how infrastructure, behavior, travel and going back and forth between indoor and outdoor environments throughout the day contribute to heat exposure. The goal is to provide a framework for the city to test and employ mitigation strategies, such as planting trees for shade or changing materials like asphalt out for cooling reflective coatings.

Several other projects in the works are exploring the reliability of infrastructure — water pumps, power lines, transformers, etc. — under extreme heat. With support from the Arizona Department of Transportation, Chester and his team of researchers have developed the capacity to estimate how frequently infrastructure failure can be expected based on rising temperatures and are working to find strategies for proactive maintenance to prevent its failure and how best to respond when it does. For example, if infrastructure is expected to fail 10% of the time during extreme heat, one solution may be to have 10% more emergency resources on hand then.

In 2014, Chester led a team of researchers on a project to assess how urban form contributes to social vulnerability to heat. The team created an interactive map where people can find cooling stations in Maricopa and Los Angeles counties. The map is updated every year with information regarding the newest set of cooling centers. 


Ariane Middel

Assistant professor in the School of Arts, Media and Engineering and the School of Computing, Informatics, and Decision Systems Engineering

Middel has been working on heat-related issues in Phoenix for almost a decade and leads the SHaDE (Sensable Heatscapes and Digital Environments) lab at ASU, where she and her team explore heat in three dimensions: heat as it can be sensed by instruments, heat as it is experienced by humans and heat as it can be modeled using computers (microclimate models and citywide, big data models).

In 2016, Middel developed MaRTy: a mobile biometeorological instrument platform that looks a bit like WALL-E. MaRTy measures how a person experiences heat in the summer. In an ongoing project, MaRTy helps to determine which shade type is most effective to keep people comfortable outdoors. MaRTy measured the cooling performance of 50 different shade types (various trees, umbrellas, awnings, shade sails, etc.), and her team is currently crunching the numbers. In collaboration with the city of Tempe, MaRTy also monitors trees in the Rio Salado Arts Park every summer to document the shade benefit from trees as they become more mature. This summer, the SHaDE lab is working on creating a fine resolution heat map of all four ASU campuses using microclimate simulations and data from MaRTy.

Middel is currently developing a thermal comfort model based on Google Street View data and deep learning techniques. The model will simulate thermal comfort from a pedestrian perspective for every street in Maricopa County. The goal is to create an app that can route people along the shadiest route (as opposed to just the shortest route). Model output will also be used in the ICARUS project, where researchers overlay the heatscapes results with output from an agent-based transportation model to simulate how people are exposed to heat as they travel.


David Hondula

Assistant professor in the School of Geographical Sciences and Urban Planning

Hondula is working with the city of Phoenix to develop a first-of-its-kind heat readiness plan that will guide how the city identifies, tracks, prepares for and responds to the dangers of extreme urban heat. The “HeatReady” program would be a comprehensive approach to heat management, much like other cities have done for catastrophic storms.

In Yuma, Hondula is working with the AZ Dept of Health Services to evaluate current public health interventions, such as cooling centers and hydration stations, as well as to identify strategies that would work best with vulnerable populations, with the overall goal of reducing illness and deaths from extreme-weather hazards. Last year, the research team conducted an on-the-ground survey of homeless individuals, and this year, they are turning their attention to senior residents.

Another effort Hondula contributes to with several other ASU researchers is the Nature's Cooling Systems project, led by the Nature Conservancy. Working with residents of three lower-income neighborhoods in Phoenix and Mesa, researchers have produced neighborhood-oriented heat action plans.

Recently, Hondula and his team analyzed heat mortality records from Maricopa County and concluded that a spike in heat-related deaths in 2016 was more likely attributable to social factors rather than abnormal heat.

Nancy Selover

Research professor in the School of Geographical Sciences and Urban Planning

In collaboration with researchers from the University of California at San Diego School of Medicine, Selover and her team completed a study in 2018 to compare how different types of cars warm up on hot days when exposed to different amounts of shade and sunlight for different periods of time. For vehicles parked in the sun during a simulated shopping trip, the average cabin temperature hit 116 degrees Fahrenheit in one hour. Dashboards averaged 157 degrees, steering wheels 127 degrees, and seats 123 degrees in one hour. For vehicles parked in the shade, interior temperatures were closer to 100 degrees after one hour. Dashboards averaged 118 degrees, steering wheels 107 degrees and seats 105 degrees after one hour. The different types of vehicles tested warmed up at different rates, with the economy car warming faster than the midsize sedan and minivan.


Sharon Harlan

School of Human Evolution and Social Change professor emeritus

Harlan has contributed to findings about the numbers of heat-related deaths and hospital visits, the weather conditions under which these incidents are likely to occur and the demographic characteristics of groups who are most at risk. She led a large study that examined the relationships between heat, socioeconomic status, land use and health in the Phoenix metropolitan area. Her research team found the highest risk of heat deaths in inner-city neighborhoods with lower household incomes, higher proportions of minorities and elderly living alone, less vegetation and hotter microclimates. Heat deaths of homeless persons were reported primarily in the inner city.

Matei Georgescu

Associate professor in the School of Geographical Sciences and Urban Planning

Georgescu and his team used computer simulations to complete some of the most sophisticated modeling of the effects of climate change and urban centers in the U.S. They found that some of today’s proposed solutions will provide only a fraction of relief from the projected heat. The team is looking into new ways of designing and building cities with climate-mitigating technologies and finding that as their predictive models increase in sophistication, they are unveiling a complex interdependency of effects.

Top photo by ASU Now