Mapping the Risk: How Environment Shapes Parkinson’s Disease Risk – First Stop: Western Pennsylvania

Environmental factors like pesticides (e.g., rotenone, paraquat), industrial solvents (TCE), air pollution (PM2.5, NO2), gut microbiome changes (antibiotics), dairy/meat intake, and even rural living/farming exposure are linked to higher Parkinson’s Disease (PD) risk, with regional variations showing higher risk in agricultural areas (Midwest/South) or near polluted urban centers, while factors like coffee/caffeine, exercise, and ibuprofen might be protective, suggesting a complex interplay where genetics load the gun but environment pulls the trigger. Over the next few blogs, we will examine different regions and the environmental factors impacting Parkinson’s disease.

Let’s start with Western PA

Parkinson’s disease (PD) is the fastest‑growing neurological disorder in the world, and Western Pennsylvania has become one of the nation’s most troubling hotspots. Research shows the region has some of the highest rates of PD in the United States, second only to parts of California. Understanding why this concentration exists can help families, caregivers, and communities push for prevention, policy change, and better support for those affected.

In Western Pennsylvania, the story traces back decades. The landscape many locals grew up with: steel mills, coal mines, coke ovens, freight corridors, and farming communities, has left a lasting impact on environmental health. Let’s explore the major environmental factors believed to be driving the elevated Parkinson’s rates in Western PA.

An Inheritance of Heavy Industry: Steel, Coal, and Coke Production

Western Pennsylvania’s industrial history is legendary, but it also created exposure to toxins strongly linked to neurological diseases.

A 2024 WPXI investigative report noted that the region’s high PD rates are connected to decades of exposure to heavy metals and airborne industrial pollutants, especially from steel mills and coke ovens that blanketed communities like Pittsburgh, Homestead, Clairton, and Aliquippa in soot and particulate matter. Researchers pointed to the region’s “legacy of steel mills, coke ovens, and coal mines” as significant contributors to Parkinson’s risk.¹

Particles released from steel production often contain manganese, a metal known to cause neurological damage. According to research cited by the Hazelwood Initiative, exposure to manganese from steel processing plants is associated with increased risk of developing Parkinson’s.² Residents who grew up during the peak industrial years recall coming home “covered in coal dust,” unaware of the long‑term consequences.

Air Pollution and Fine Particulate Matter (PM2.5)

Air pollution has recently become one of the most researched environmental links to Parkinson’s, and Western PA fits the pattern.

A landmark 2023 study in Neurology found that individuals living in areas with median levels of air pollution experienced a 56% higher risk of developing Parkinson’s disease than those living in cleaner regions. The researchers identified the Mississippi‑Ohio River Valley, which includes Western Pennsylvania, as a major PD hotspot.³

Pollution in this region often contains combustion particles from traffic and industry as well as heavy metals from manufacturing, both of which have been associated with cell death in the brain region involved in Parkinson’s.

Further supporting evidence comes from a 2024 JAMA Network Open case‑control study, which found that higher exposure to PM2.5 and nitrogen dioxide (NO₂) was significantly associated with increased Parkinson’s risk, particularly in metropolitan and industrial areas.⁴

Chemical Exposure: Pesticides, Herbicides & Solvents

While Western PA is known for steel, it’s also an expansive agricultural region. Rural communities frequently encounter environmental exposures similar to those seen in California’s agricultural hotspots, the highest‑rate region for PD in the country.

The Parkinson’s Foundation identifies several chemical exposures linked to PD:

• Paraquat, a widely used herbicide
• Other pesticides and herbicides
• Solvents such as trichloroethylene (TCE)
• Polychlorinated biphenyls (PCBs)

These toxins have been associated with PD risk in multiple studies.⁵

UPMC neurologists in Pittsburgh explain that the combination of industrial toxins plus agricultural chemicals may explain why Western PA has such high rates today.⁶

Aging Population and Long-Term Exposure

Western Pennsylvania’s population is older than the national average. Because Parkinson’s typically develops after decades of cumulative exposure, older communities disproportionately reveal the long-term effects of environmental toxins. The high occurrence of PD in this region is partly due to an aging population combined with lifetime exposure to industrial pollutants.

What Can We Do?

Understanding the environmental roots of Parkinson’s in Western PA is a powerful first step. Here are key actions that can help:

1. Advocate for stricter pollution controls – Reductions in PM2.5 and industrial emissions can directly reduce future PD risk.
2. Support the cleanup of old industrial sites – Brownfields, old factories, and contaminated groundwater remain sources of ongoing exposure.
3. Promote safer agricultural practices – Limiting pesticide and herbicide use reduces risk in rural communities.
4. Encourage regular neurological screening for high‑risk residents – Those who grew up near mills, mines, or farms can benefit from early detection.

Final Thoughts

Western Pennsylvania’s high rates of Parkinson’s Disease are not random. They are the result of generations of environmental exposures, from steel mill pollution and coal dust to pesticides and traffic emissions, layered over genetic susceptibility and aging populations. By recognizing these risks and pushing for cleaner, safer communities, we can help change the trajectory for future generations.