Urban areas, with their asphalt roads and concrete buildings, absorb and release heat back into the environment at higher rates than the flora and fauna of natural landscapes.

It’s called the heat island effect. The Data-Driven EnviroLab at UNC-Chapel Hill studies how to mitigate It.

Angel Hsu, director of DDL and a public policy associate professor in the UNC College of Arts and Sciences, has researched environmental issues and how they disproportionately affect communities for over a decade. She has trained companies and governments how to measure and account for their greenhouse gas emissions and worked with businesses and governments in Mexico, Brazil and China to combat environmental challenges.

“Working with communities there, you really understood the value of data, policy and management,” said Hsu. “These were countries that had no international obligation or commitments to reduce their emissions, but they realized it’s an advantage when you have data that allows you to measure the problem and identify hotspots.”

Hsu eventually created the Urban Environment and Social Inclusion Index, a platform for cities around the world to see how they perform on environmental markers such as air quality, heat and water stress. A grant from the Belonging Forum brought the vision to life and allowed Hsu and DDL to collect preliminary data needed for additional funding.

Exploring disparities and solutions to heat stress

As a follow-up to the UESI index, the lab used a $1.5 million NASA grant to launch an extensive urban heat mapping project to develop heat stress models and eventually inform policy.

The team uses a combination of direct measurements, machine learning and microclimate modeling to collect data. Sarah Berk, a postdoctoral research associate at DDL, spent the summer placing sensors across Raleigh with the help of UNC Institute for the Environment interns Carlos Carranza and Vivien Hines and graduate student Izzy Bukovnik. The measurement data is used to train machine learning models.

“We input information on land cover, like how much tree canopy was in the area, how dense the buildings were and how reflective services in the area are,” Berk said. “Then the model predicts air temperature in areas where we don’t have the data.”

While the collected data will inform how best to mitigate heat stress, the team’s methods have already been used to assess the efficacy of the City of Raleigh’s ongoing pavement rejuvenation project, which uses titanium dioxide to reflect sunlight.

An interdisciplinary, long-term goal

The heat stress project is just one of several at DDL aiming to initiate change in the climate sector.

“If we’re talking about climate and environment, that’s interdisciplinary by nature. Climate is not going to be solved by a single discipline,” said Hsu. The only way to solve the problem, she said, is to combine strong suits across the board.

When she started DDL in 2016, Hsu made the decision to omit her last name from the lab’s title – a common convention researchers follow.

“I wanted this to be a movement. I wanted people who were part of the lab, whether they’re students or collaborators or other faculty, I wanted them to feel like they’re part of the movement,” said Hsu. “We want to use data to drive environmental decision making.”

Angel Hsu and the Data-Driven EnviroLab credit much of their success to the ongoing support of the Belonging Forum, formerly known as the Samuel Centre for Social Connectedness. The forum’s continued funding and dedication to DDL’s mission have allowed the lab to launch pilot work crucial to getting projects off the ground and garnering support from federal organizations and grants.