When heatwaves hit Tacoma, researchers from Portland State University hit the streets, driving around with highly sensitive thermometers mounted to their cars to collect real time information about the hottest places in cities.
Their goal? To identify “urban heat islands,” or areas that can run 10 to 20 degrees hotter than other areas of the city and can pose serious health risks to the people living and working there.
Using interactive maps, the researchers overlay their location-specific heat data with information about demographics, air pollution, and local landscape features like roads, buildings, and trees—creating comprehensive tools that can help local governments pinpoint the most vulnerable areas of their cities and develop strategies for mitigating negative health impacts of extreme weather events.
PSU urban studies professor Vivek Shandas has worked for years to develop a mapping tool, and views Tacoma as a “living laboratory” or pilot site. The Tacoma campaign will help them achieve a goal of developing a generalizable mapping system that any community can use to describe differences in temperatures across an urban area.
“With climate change, we expect summer heatwaves to become longer and more intense and frequent,” said Shandas, Research Director for of PSU’s Institute for Sustainable Solutions. “By identifying characteristics of neighborhoods and households that are the most vulnerable, we can develop models to reduce the health impacts of intense heatwaves nationally.”
Urban heat islands have a two-fold effect on health. The heat poses risks of dehydration, especially for elderly, homeless, and low-income communities, but it also turns air pollution into smog, increasing potential complications for people with heart or lung conditions.
Shandas and his team have found that areas with high concentrations of asphalt, large buildings, and parking lots tend to run hotter, while areas with more tree canopy and greenery, and lighter in color tend to run cooler.
“This research is key to our climate resilience policy and planning work,” said Michele Crim, climate policy and planning manager for Portland’s Bureau of Planning and Sustainability where Shandas refined the monitoring and mapping techniques. “It enables city staff to identify the specific hot spots in Portland where we need to prioritize investments and programs to serve Portlanders that are most vulnerable to heat events.”
Strategies for reducing deadly impacts of heatwaves range from opening more public air-conditioned spaces to strategically removing pavement, adding trees, and varying the heights of buildings to increase natural airflow.