• 14 Jul, 2024

New Fabric Makes Urban Heat Islands More Bearable

New Fabric Makes Urban Heat Islands More Bearable

This year has already witnessed massive heat waves around the globe, with cities in Mexico, India, Pakistan, and Oman reaching temperatures near or above 50 degrees Celsius (122 degrees Fahrenheit).

As global temperatures and urban populations rise, cities are increasingly becoming "urban heat islands," where densely packed conditions and thermal radiation from pavement and skyscrapers trap and amplify heat. With 68% of the global population expected to live in cities by 2050, this is a growing and potentially deadly problem.

In a paper published in *Science*, researchers from the UChicago Pritzker School of Molecular Engineering (PME) introduced a new wearable fabric designed to help urban residents cope with extreme heat caused by global climate change. This fabric has potential applications in clothing, building materials, car design, and food storage.

Tests conducted under the Arizona sun showed that the new material stayed 2.3 degrees Celsius (4.1 degrees Fahrenheit) cooler than fabrics used in outdoor endurance sports and 8.9 degrees Celsius (16 degrees Fahrenheit) cooler than commercial silk commonly used for summer clothing. The team hopes this innovation will help reduce heat-related hospitalizations and deaths in urban areas.

"We need to reduce carbon emissions and make our cities carbon-negative or carbon-neutral," said PME Assistant Professor Po-Chun Hsu. "But meanwhile, people are feeling the impact of these high temperatures."

Consider the Environment

Current cooling fabrics for outdoor sports work by reflecting sunlight in a diffuse pattern to prevent blinding glare. However, in urban heat islands, the sun is not the only source of heat. Buildings and pavement emit thermal radiation that exacerbates the heat, making urban environments particularly challenging.

This means many materials that perform well in laboratory tests may not be effective in real-world urban settings, such as in Arizona, Nevada, California, Southeast Asia, and China, which are expected to experience severe heat waves in the coming weeks.

"People normally focus on the performance or the material design of cooling textiles," said Ronghui Wu, co-first author and postdoctoral researcher at PME. "To make a textile that has the potential to apply to real life, you have to consider the environment."