Thursday, October 15, 2026

Green space is linked with fewer gun-related homicides — but not everywhere

Study uses Google Street View and AI to measure greenery at the scene of fatal shootings

Ohio State University

COLUMBUS, Ohio — Our physical surroundings affect everything from personal well-being to a neighborhood’s safety. A new study from The Ohio State University finds that when it comes to preventing gun violence in a community, green space can help, but its location makes a big difference.

A growing body of research shows that urban green spaces — parks and other areas lined with plants, grass and trees — improve community and individual health outcomes by encouraging physical activity, reducing stress and improving air quality. They’ve also been associated with reduced gun violence and other violent crimes, but the relationship is complex, and not fully understood.

While attending a recent conference, the study’s lead author, Gia Barboza-Salerno, made a point that resonated with fellow researchers who study urban greenery and violence prevention: When it comes to the effects of green space on communities, local context matters.

“It’s not as simple as planting a tree and thinking that alone will solve it,” said Barboza-Salerno, an associate professor in Ohio State’s colleges of social work and public health. “Even though we know urban greenery is a great prevention measure for a lot of reasons, we don’t understand how or whether there’s an interaction between where this greenery is — the local context in which the greenery sits — and a subsequent reduction in violence.”

That question became the basis for a study published this month in Urban Forestry & Urban Greening. Barboza-Salerno’s team looked at how green space, neighborhood disadvantage and gun violence intersect in Cook County, Illinois, which reported the most homicides in the U.S. in 2022.

“Firearm-related violence is a public health crisis in this country, and it disproportionately affects young Black males,” Barboza-Salerno said. According to research cited in the study, racial and ethnic disparities in violence are often linked to factors such as poverty, limited educational and employment opportunities, economic inequality and residential segregation. Urban green spaces may offer protective benefits, but no previous study had specifically investigated greenery near the locations of firearm-related deaths as it would be seen from the street level, from a pedestrian’s point of view, according to the study.

“We really wanted to show in this paper that urban planning is a critical part of public health prevention by evaluating the quality of streets that people traverse daily in their activity spaces,” Barboza-Salerno said.

As director of Ohio State’s Investigating Spatial Structures in Urban Environments (ISSUES) Lab, Barboza-Salerno leads a research group that uses advanced spatial statistics, geospatial artificial intelligence (GeoAI) and machine learning to understand how neighborhood environments shape health, safety and social well-being.

For this study, the team examined 899 firearm homicides and 2,256 natural deaths in the county in 2023 and compared them with natural deaths of people similar in age, sex and race who died nearby. By using Google Street View images and machine learning tools, they measured the amount and types of greenery a person would actually see from the street where each death occurred.

The study found that more visible greenery, tree canopy and green space along walkable streets were linked to lower odds that a death in that location was a firearm-related homicide. But the benefits of green space aren’t universal. Tree cover and greenery offered the most protection in less disadvantaged neighborhoods, while in the most disadvantaged neighborhoods, being closer to a park was actually linked to a higher risk of firearm homicide.

The researchers attribute this finding to multidimensional measures of social deprivation, including poverty, structural housing disadvantage, economic inequality, family structure and income, having a stronger impact than a neighborhood’s green spaces.

“Green space is very important and critical for violence prevention, but not all green space matters equally,” Barboza-Salerno said. “Basically, if you lived in a socially advantaged environment, having green space mattered more for reducing violence than in a socially disadvantaged area. Green space should be thought of as a violence-prevention intervention, yet the green space that does the most protective work tends to be concentrated in more advantaged neighborhoods. That’s a double inequity: disadvantaged areas get less quality green space, and the green space they get is less protective without other supports.”

When parks in disadvantaged neighborhoods aren’t well-maintained or used regularly, they can become more of an eyesore than a protective factor, Barboza-Salerno said. Whereas in neighborhoods with more resources, well-kept parks have a beautification effect that can improve how people feel, and strengthen neighbors’ willingness to look out for one another.

“In these very [disadvantaged] areas, there’s a lot of economic disinvestment, and that is the association with violence, not the park per se,” Barboza-Salerno said.

The researchers caution that the study looked only at environments, not individuals. “We only looked at the location of death for the person in the context of the environment at that moment,” said Taylor Harrington, a doctoral candidate in public health and a co-author of the study. “It doesn’t encapsulate their whole lived experience or exposure throughout life up until that point.”

Barboza-Salerno has seen green space work as part of a broader effort. As the lead researcher at the Violence Prevention Collaborative in Boston and Director of Research for the Dudley Street Neighborhood Initiative (DSNI), Barboza-Salerno partnered with youth development organizations that employed young people to fix up local parks. The work gave them new skills and changed how neighbors perceived them.

Among other things, parks can provide safe places for children to play, socialize and have positive reciprocal interactions. Alongside housing and food security, “it’s one part of a comprehensive community-building approach that needs to be scaled to see effective violence prevention in this country,” Barboza-Salerno said. “If we think carefully about where green spaces are placed and why they make a difference, this could be huge.”

Other Ohio State co-authors of the study are Balaji Ramesh and Jeffrey Wing of the College of Public Health.

Contact: Gia Barboza-Salerno, barboza-salerno.1@osu.edu

Written by Elizabeth Weinstein, weinstein.137@osu.edu

Journal

Urban Forestry & Urban Greening

DOI

10.1016/j.ufug.2026.129597

Method of Research

Imaging analysis

Subject of Research

Not applicable

Article Title

Street-view measures of urban greenness, area-level deprivation, and the risk of firearm-related homicide: A matched case-control study

Article Publication Date

15-Oct-2026

Engineers make quality, low-cost carbon fiber from coproducts of paper, energy production

Iowa State University

High-value carbon fiber — image:
Iowa State engineers are turning the low-value ingredients in these beakers into the high-value carbon fiber on the lab bench. Left to right are Tannon Daugaard next to spools of carbon fiber; Abdulrahman A. B. A. Mohammed holding a beaker of bio-oil; and Xianglan Bai holding a beaker of lignin.
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Credit: Iowa State University/Christopher Gannon.

AMES, Iowa – Xianglan Bai illustrates her development of biobased carbon fiber with two beakers in researchers’ hands.

The first contains low-cost, low-value and plentiful softwood kraft lignin, the tough stuff that strengthens and waterproofs the cell walls of trees and plants. The natural binder is a coproduct of paper production.

The second contains a low-value, watery fraction of bio-oil, a liquid fuel produced by a thermochemical process called fast pyrolysis. The process uses heat to break down corn stalks, wood chips and other biomass to produce a bio-oil for heating that can be divided into fractions with various properties and performance characteristics. (The process also produces a solid biochar that can be used as fertilizer.)

“We’re taking lignin, considered a low-value byproduct of the paper and pulp industry, and aqueous bio-oil, also considered to be a low-value product, and putting them together to come up with a high-value product,” said Bai, an Iowa State University professor of mechanical engineering and an associate director of Iowa State’s Bioeconomy Institute.

“This is where chemistry and materials science beautifully meet,” she said.

‘Real-world solutions’

Carbon fiber is a strong and ultra-lightweight material used in aerospace, transportation, wind energy and infrastructure applications. You’ll also find it in sport and performance industries such as high-end bicycles and motorsports.

It is typically manufactured using petroleum-based materials. But the high costs of those precursors are raising the costs of carbon fiber and limiting its use to premium applications.

The U.S. National Science Foundation, as part of its Translation to Practice program, which aims to “turn scientific discoveries into real-world solutions,” is supporting further development of Bai’s biobased carbon fiber with a four-year, $2 million grant.

It’s the ‘thermo-mechanochemistry’

Bai and her research group have been researching the production of biobased carbon fiber since 2015, with much of the work focused on lignin as a potential source material.

This wasn’t a new idea. Japanese researchers started looking at lignin for carbon fiber back in the 1960s. But the performance of the resulting carbon fiber was inferior to petroleum-based versions.

Even after decades of trying, the biobased carbon fibers didn’t have the performance levels required for use in cars and other performance-critical industries.

With the support of several grants from the U.S. Department of Agriculture, Bai and her research team have developed several patented and patent-pending technologies “that enable the production of low-cost, lignin-based carbon fibers with exceptional performance properties,” Bai said.

One example is introducing “thermo-mechanochemistry” of lignin, a new material chemistry her group recently discovered. The process heats lignin and puts the spun fiber under increasing mechanical stress, fundamentally changing its chemical transformation and the evolution of its material structures. The result is much stronger carbon fiber while maintaining costs below $5 per pound.

Researchers measured a tensile strength, or stretching, up to 2.45 gigapascals in the biobased carbon fiber and a tensile modulus, or stiffness, up to 236 gigapascals. That easily meets U.S. Department of Energy carbon fiber recommendations for the auto industry of 1.72 for tensile strength and 172 for tensile modulus while keeping costs from $5 to $7 per pound.

Another example of innovation in Bai’s lab is using watery bio-oil to modify non-softening lignin into melt-spinnable precursors. The modified lignin reduced the stabilization time for spun fiber from tens of hours to two to four hours, reducing production bottlenecks and costs.

Commercial production

The new grant will allow Bai, her research group and industry collaborators to move from batch production in a lab to commercially relevant continuous production.

Additional leaders working on that transition include Tannon Daugaard, an engineer and faculty member for the Bioeconomy Institute and a co-founder of Rise Energy, an Ames-based startup; and Ryan Smith, deputy director of the Bioeconomy Institute, also a co-founder of Rise Energy, which is supplying bio-oil to the project.

Major collaborators include Harper International of New York state, Latis Materials of Maine and Rise Energy.

The result could boost the value of paper and bio-oil production while providing the country with a domestic source of high-performance, biobased carbon fiber.

“Commercializing this breakthrough technology could significantly reduce manufacturing costs,” the researchers wrote in a project summary, “while securing a reliable domestic supply of a critical structural material, thereby strengthening U.S. economic competitiveness.”

Lignin, bio-oil and carbon fiber.

Credit

Iowa State University/Christopher Gannon.

Footprints in the (white) sand: Humans experienced abrupt environmental shifts during the last ice age

University of Arizona

image:
Kathleen Springer and Jeffrey Pigati collect samples for environmental change analysis from a trench in the White Sands playa.
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Credit: Jessica Tierney

Expanded excavations at White Sands National Park in New Mexico have provided researchers an opportunity to refine the age of the oldest human footprints in North America and establish a deeper understanding of the landscape and environmental conditions at the time humans were present there.

The new study, published in Science Advances by a team of researchers including the University of Arizona, the United States Geological Survey and other partners, reveals a dynamic environment indicating the humans who left their tracks along an ancient lake shore experienced abrupt changes in temperature and water availability within their lifetimes.

The research team previously discovered and confirmed the White Sands human footprints to be the oldest evidence of human presence in North America, placing people on the continent thousands of years earlier than once thought.

The research details innovative extraction procedures used to isolate up to 75,000 individual pollen grains per sample and refined dating methods used at the USGS Radiocarbon Laboratory. This resulted in a more precise age of the site and reaffirmed the White Sands footprints date to between 23.5 and 21.7 thousand years ago, or during the Last Glacial Maximum. The new chronology was key to unlocking the rest of the story, which includes a deeper understanding of the abrupt environmental changes that early humans in North America faced.

The researchers used the new chronology to investigate the climate and environmental changes at a timescale equivalent to a human generation, or approximately 50 years, which is rare for terrestrial paleoclimate archives of this time period from the southwestern U.S.

"The White Sands sediments are unique in that they allow us to reconstruct environmental conditions during the last ice age at a very high temporal resolution, so that we can see fluctuations that were relevant for the humans present at that time," said co-author Jessica Tierney, a professor at the U of A Department of Geosciences.

Tierney applied her expertise in the analysis of geochemical signatures captured in sediments, which she combined with fossil pollen from the plants growing in the surrounding landscape, to reconstruct temperature, precipitation, aridity and plant communities. The results show the climate at White Sands was dynamic. Humans witnessed a complete turnover of the landscape from conifer forest to sagebrush and oak steppe and the recession of Lake Otero, a massive lake that would have covered most of what is White Sands National Park during the last ice age. By measuring isotopes – elemental atoms that differ by their number of neutrons, in this case, hydrogen – in leaf waxes of preserved plant material, Tierney's group at the U of A discovered that there were also swings in water availability within a century that included severe aridity during an abrupt warming event also recorded in ice core samples from Greenland.

"This tells us that local changes in aridity at White Sands were quite large and followed global climate shifts," Tierney said.

During the last glacial maximum, when the humans left their footprints in what likely was a muddy plain, temperatures in the Southwest were generally cooler, around 50 degrees Fahrenheit, as opposed to today's annual mean temperatures around 60 degrees in that area, Tierney explained. During the sudden shift documented by pollen in the sedimentary layers, vegetation changed from pine forest to pinyon and juniper, all within about 100 years.

Tierney said that varying amounts of pollen left behind by Ruppia, an aquatic plant that likes to grow in desert streams and springs, indicate Lake Otero's water level went up and down over the course of about 1,500 years.

"Eventually the lake shrunk more and more until it gave way to a flat playa," she said. "And throughout that whole sequence, people were walking there, leaving their tracks alongside those of mammoths, giant sloths and dire wolves."

Having an exquisitely preserved record of the environmental conditions and changes, such as rainfall, temperatures and vegetation in the same place with tracks left by humans and wildlife at the same time is extremely unique for the Southwest, if not globally, Tierney added.

"Even though these footprints have been buried in the gypsum mud for more than 20,000 years, they look like someone walked out on the playa yesterday," Tierney said. "This is an incredibly rare opportunity to be able to do paleoclimate reconstruction and combine it with archeology in the same exact place."

Next, the researchers want to delve deeper into what exactly happened at the time – what mechanisms may have been at work that would have caused a warming event in Greenland to cause drying in the American Southwest.

"This study fulfilled a long-term research goal at White Sands – to expand the originally published footprint site and sample for environmental indicators to help further our understanding of the complete context of conditions at the height of the Last Glacial Maximum," said Kathleen Springer, USGS research geologist and co-lead author on the paper. "It's remarkable that early humans in the region were real-time witnesses to a rapidly changing environment discernible within a human lifetime – that is really food for thought."

Ed Jolie, Clara Lee Tanner Associate Professor of Anthropology at the U of A and a study co-author, said the findings "humanize the deep Indigenous past of the Americas." Jolie, who is Oglala Lakota and Hodulgee Muscogee, is also associate curator of ethnology at Arizona State Museum.

"This research continues to remind scientists and the wider public that these resilient ancient human populations are the ancestors of contemporary Indigenous peoples, providing important scientific evidence in support of sovereign Native nations' oral traditions and reinforcing the fact that we have been here since time immemorial," Jolie said.