Graduate Student Spotlight: Jonathan Tollefson

In a working paper, an IBES graduate affiliate sheds light on the historical link between segregation and environmental inequality.

Environmental pollution may have shaped the formation of racially segregated neighborhoods, a study by Brown Ph.D. candidate Jonathan Tollefson suggests.

For years, researchers have understood that there is a complex relationship between pollution and segregation in cities. But most research on environmental inequality utilizes data from after the 1980s, when racial segregation was already firmly established as a neighborhood-level phenomenon.

“That’s a relatively recent structure,” said Tollefson (who uses they/he pronouns), noting that segregation was once primarily seen on a street level. “Urban sociologists haven’t been able to understand how the environment shaped segregation when it was first established in the early 20th century as this pattern of large, contiguous, homogeneous neighborhoods,” they added.

Archival data unlocks new perspectives

Tollefson’s working paper, “Environmental risk and the reorganization of urban inequality in the late 19th and early 20th century,” aims to address this knowledge gap.

The study centers upon seven cities — Baltimore, Cleveland, Minneapolis, New Orleans, San Francisco, Oakland, and Providence — and focuses on the manufacturing gas industry, one of the “first urban fossil fuel utilities” and a “major source of environmental pollution that people at the time recognized as being really important to how cities were structured,” Tollefson said.

Using census data and historical maps to locate industrial sites, Tollefson was able to elucidate how personal demographics were linked to the proximity of industry.

The manufactured gas industry — the focus of Tollefson’s study — was one of the first major fossil fuel-based utilities. (Photo: OpenSFHistory)

sanborn map — To overcome the lack of data from the era, Tollefson used maps from the Sanborn Fire Insurance company to locate gasworks. (Photo: Library of Congress)

Tollefson hypothesizes that proximity to gasworks and environmental exposure could have been a driving force behind residential segregation. (Photo: New York Public Library)

Tollefson’s analysis begins in 1880 when residential segregation was organized at relatively small spatial scales. In some cities, such as New Orleans, non-white residents were clearly more likely to live close to industrial sites. Others, such as Minneapolis, saw less of a correlation.

However, “over the next 50 years, this consistent pattern is revealed, which is that racial inequality in environmental exposure increases across every case that I’m researching,” Tollefson said. “It’s race that emerges as the only consistently positive predictor across cases.”

“On an empirical level, my research tells me that racial environmental inequality emerged a lot earlier than people have been able to show,” they added. “It also suggests that the environment likely played an important role in how neighborhood racial segregation started to form.”

“ Racial environmental inequality ... may be not just an outcome of segregation, but a potential cause ”

Jonathan Tollefson IBES Graduate Affiliate, Ph.D. candidate in sociology

These findings can help policymakers, researchers, and community members better understand the enduring impact of segregation in their regions while revising previous theories of environmental inequality.

In fact, racial environmental inequality could be “fundamental to the structures that shaped the modern city,” Tollefson hypothesizes. Exposure to hazardous environments “may be not just an outcome of segregation, but a potential cause.”

Tollefson’s study has been recognized in the field of environmental sociology, having received the 2023 IPUMS USA Student Research Award; the 2024 Brent K. Marshall Student Paper Award from the Environment and Technology Division of the Society for the Study of Social Problems; and the 2024 S4 Graduate Student Paper Prize from Brown University. It also received honorable mentions for the Eastern Sociological Society’s 2024 Candace Rogers Student Paper Award and the 2024 Graduate Student Paper Award from the Environmental Sociology Section of the American Sociological Association.

Fewer boundaries, richer experiences

As a doctoral advisee of Scott Frickel — a professor in both IBES and the Department of Sociology — Tollefson has found that working across departments has helped them connect their interests.

“Doing research in the IBES world with a disciplinary theoretical basis in sociology has made for a really fun combination,” they remarked.

Now, as Tollefson revises their working paper for publication, they aim to continue studying the history of segregation and its ties to environmental exposure.

“Segregation becomes a relatively fixed and long-run structure that shapes everything about how cities are organized,” they said. “I would love to see how early 20th-century environmental processes might have shaped these subsequent structures in a direct way.”