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ASU researchers help prepare for Arizona's killer heat

woman drinking water in the heat
May 12, 2014

Heat killed 139 people in Arizona in 2013. The best way to reduce that number is to be prepared. A new report, The Trend in Morbidity and Mortality from Exposure to Excessive Natural Heat in Arizona, shows heat is linked to an average of 118 deaths every year since 2000. It also shows that men account for seven of every 10 heat deaths in Arizona.

The National Weather Service says the beginning of our summer will be even hotter than normal this year.

Researchers at Arizona State University are part of a multi-agency team that is providing heat resources for people in need and working to determine causes of heat-related illness and death. The team includes the Arizona Department of Health Services (ADHS), the National Weather Service, the Phoenix Heat Relief Network, county health departments, emergency management agencies, non-profits and others. 

ASU researchers Sharon Harlan and David Hondula are contributing 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.

“The health risks associated with high temperatures are unequally distributed across population groups,” says Harlan, a professor in ASU’s School of Human Evolution and Social Change.

Harlan leads a large study that examines 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. 

In 2013, 526 people were admitted to hospitals in Arizona because of heat, and 2,242 were treated in emergency rooms. Almost half of the state’s heat-related emergency department visits in 2013 were young adults between the ages of 15-44 (1,102).

“The hundred or more deaths and thousands of hospitalizations we see in our state each year associated with heat are preventable,” says Hondula, a postdoctoral fellow in ASU’s Center for Policy Informatics, part of the College of Public Programs. “Our growing capacity to analyze and collect data about how the environment impacts people enables us to enhance existing heat-health intervention strategies and design new ones.”

Hondula will work with the Maricopa County Department of Public Health and Arizona Department of Health Services this summer to evaluate the effectiveness of “cooling stations” used to provide water and refuge to people in need.

A team led by Mikhail Chester, assistant professor in the School of Sustainable Engineering and the Built Environment, focuses on assessing 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. You can see the map at

The ADHS offers additional information about ways to prevent, recognize and care for heat-related illnesses on their website.

“High temperatures start early in Arizona. Our most serious months for heat illness are May through September,” says Matthew Roach, ADHS Climate & Health Program manager. “People need to be prepared – be aware of temperatures, plan outdoor activities accordingly and know the symptoms of heat illnesses.”

The National Weather Service Climate Prediction Center three-month outlook calls for a greater chance of above-average temperatures for the first half of summer in much of the U.S. Southwest, including Arizona. The National Weather Service Phoenix office, ADHS, and other partner groups have teamed up to initiate the new Arizona Heat Awareness Week, running May 12-16. 

“Excessive heat in our desert climate climbs to the top of public health priorities every summer. We want to make sure people continue being active, but that they have to be smart about it,” says Will Humble, ADHS director. “We all share a community responsibility to help those in need stay cool. One way is to donate water or hold a water drive at your work. The donated water helps people who go to cooling shelters in the extreme heat.”

The website was developed with support from the National Science Foundation's Infrastructure Management and Extreme Events program (award 1335556). Harlan’s research is supported by the National Science Foundation’s Directorate for Geosciences (award 0816168). Hondula is supported by the Piper Trust Health Policy Informatics Initiative.