Noise pollution disproportionately affects marginalized communities and area wildlife: Study

Redlined, marginalized communities tend to experience an outsized amount and volume of urban noise, a new study has found.

Such unseen pollution — which has been associated with negative effects on wildlife and people — are examples of the ongoing injustice endured by certain populations, according to the authors.

“We need to be thinking more about how these systemic injustices and problems are manifesting to shape ecology and evolution,” co-author Sara Bombaci, an assistant professor at Colorado State University, said in a statement. 

Bombaci and her colleagues in the university’s department of fish, wildlife and conservation biology published their findings Monday in the journal Nature Ecology & Evolution.

Ecological degradation exacerbates existing inequalities encountered by those living in formerly redlined areas — since people benefit from nature and wildlife, Bombaci explained.

Now illegal, redlining was the discriminatory practice of refusing loans or services to those living in non-white areas.

“The socioecological consequences of racially targeted zoning, such as redlining, need to be considered in urban planning,” the authors stated.

With more than 270 million residents living in urban areas across the country, the researchers strived to pinpoint the interplay between inequitable noise pollution and ecological change.

To do so, they began by investigating urban noise distribution across historical racial divisions in 83 U.S. cities.

Assessing hundreds of studies on the effects of noise on wildlife, they found that louder noise levels more commonly correspond with redlined urban areas.

The practice of redlining officially began in 1933, when the Home Owners’ Loan Corporation started assigning rankings to areas based on race and wealth, the authors noted.

Grade A signified a wealthier and whiter neighborhood, while Grade D areas housed people from various races and ethnicities.

Although redlining was outlawed in 1968, decades of divestment in these areas resulted in disparities that persist today, the researchers explained.

The authors found that Grade D neighborhoods experience 17 percent higher maximum noise levels than Grade A neighborhoods.

Meanwhile, Grades C and D areas more frequently experience maximum noise levels about the threshold known to cause physical pain and stress in humans, per the study.

“This is directly linked to structural racism,” Bombaci said. “There’s a clear signal that ties directly to whether these communities were redlined.”

Among the effects of noise pollution on human health are hearing loss, insomnia, hypertension and heightened risk of heart disease and stroke, the researchers noted.

As far as wildlife is concerned, persistent noise can alter animal behavior, including communication, fitness, foraging, mating, movement and reproduction.

Existing disparities in noise pollution levels may be wide, but the authors also identified ways cities are taking action to bridge this gap.

For example, they observed the city of Denver is working on making urban planning more equitable and on improving access to parks and green spaces in underserved communities.

But to maximize the benefits of such changes, Bombaci stressed that noise should also be considered while formulating such plans.

“If we’re adding green space without mitigating impacts of noise, we might not be fully recognizing the benefits of these green spaces,” she said.