Denver’s Worst Smells Linger in Marginalized Neighborhoods, Study Finds
In a new study examining environmental justice and urban air quality, researchers found that bad odors from sources like marijuana grow operations, pet food factories, and construction smoke are more likely to impact lower-income and predominantly non-white neighborhoods in Denver. The research, published in the Journal of Exposure Science and Environmental Epidemiology, analyzed nearly a decade of odor complaints filed with the city and revealed that areas historically shaped by redlining and structural inequities are more likely to host odor-emitting facilities.
The University of Colorado Denver-led team used machine learning to cluster nearly ten years of complaint data and mapped it against 265 facilities required to have odor-control plans. The result: neighborhoods with less wealth, education, and political influence were more likely to be located near sources of persistent odors. Despite this proximity, residents in those neighborhoods weren’t filing the most complaints—those came mostly from gentrifying or more affluent areas, possibly because residents there are more empowered to take action.
Odor exposure isn’t just an annoyance; it’s linked to elevated stress, headaches, nausea, and other health impacts. Unlike regulated pollutants like ozone or nitrogen dioxide, smells are governed locally and are harder to track, making enforcement inconsistent. Yet, researchers argue that odors are a tangible way cities like Denver can address air quality disparities with targeted action.
The study also raises questions about underreporting in vulnerable communities, suggesting that residents may be unaware of their rights or feel that their complaints won’t lead to change. As next steps, the research team plans to layer in wind data to better understand how smells travel—and why some communities bear the brunt of industrial and environmental nuisances.
