Urban areas facing a one-two punch of heat and air pollution could fight back with changes in city planning, according to a new study published in Nature Communications last month.

The study, co-authored by Gregory Carmichael, University of Iowa Karl Kammermeyer Professor of Chemical and Biochemical Engineering, asserts that as cities grow, they become “urban heat islands,” an effect that merges with air pollution.

The dual threats need to be dealt with simultaneously, according to the study.

The research team used computer models to consider multiple objectives and the interplay of heat and pollution to optimize spatial planning of cities in a way that reduces both heat and air pollution.

The study offers three strategies for city planners: 

• Build more in areas where winds can carry heat and pollution away

• Avoid very dense development and instead aim for moderate density 

• Increase green space (like trees and parks), which helps cool the air and filter pollution  

With the right layout, air can move more freely through the city, which helps clear pollution, while wind patterns can also help reduce heat buildup, according to the study.  

Collaborators include researchers from the Department of Geography at Hong Kong Baptist University in Hong Kong, China; and the John A. Paulson School of Engineering and Applied Sciences at Harvard University in Cambridge, Massachusetts. 

The study is available at https://www.nature.com/articles/s41467-026-73855-x.