According to reputable researchers, clinicians, and other scientists around the globe who have spent years studying the effects of Parkinson’s disease on the human body, their collective conclusions have shown that environmental factors created by humans are an important influence in the disease that has led to the growing number of Parkinson’s cases worldwide.
Hazardous chemicals are believed to be responsible for many of the diseases we have today, quietly influencing the public through decades of widespread exposure, including several forms of cancer and neurological diseases. These chemicals are generally thought to affect gene expression, mitochondrial function, or cellular damage throughout the body, mechanisms that researchers believe may contribute to diseases such as Parkinson’s. There are a known few of these toxins that have risen to the status of infamous due to their effects on large portions of the population, including pesticides like Paraquat, Rotenone, and Chlorpyrifos, and industrial solvents such as Trichloroethylene and Polychlorinated biphenyls.
What has also risen to the ranks of toxic is the air we breathe, thanks to chemicals released through emissions from cars and other industrial sources that contribute to a growing list of respiratory, cardiovascular, and neurological health risks, including Parkinson’s disease. These emissions are released as ultrafine air pollution particles that travel from the nose to the brain. by means of the Olfactory nerve, bypassing the blood–brain barrier, and influence a growing list of health issues for millions of people who live in these heavily influenced urban areas with high levels of heart disease, stroke, high blood pressure, Asthma, and chronic obstructive pulmonary disease, or COPD.
The tiny airborne particles, capable of traveling from the nose to the brain, affect various neurological conditions, such as cognitive decline and memory issues, which are sometimes associated with a higher risk of dementia. They have also been connected to damage in dopamine-producing neurons within the Substantia Nigra, a brain region crucially linked to Parkinson’s disease.
In cities and communities across the globe, scientists are piecing together a troubling picture of how polluted air may reshape the human body. A growing body of research has identified several biological changes associated with prolonged exposure, including:
Mexico City: Research from Mexico City, one of the most polluted urban areas in the world, found early signs of Parkinson’s-related brain changes, including alpha-synuclein buildup in the brains of young children and teens exposed to severe air pollution.
Seoul, South Korea: Researchers found that after studying 78,830 adults concluded that people exposed to higher levels of nitrogen dioxide, mostly produced by vehicle exhaust, had a greater chance of developing Parkinson’s disease.
Denmark conducted a nationwide study by following more than 3 million people and found higher Parkinson’s rates in areas with greater exposure to fine particle pollution (PM2.5) and traffic-related pollution.
Taiwan: Researchers using the country’s National Health Insurance database found long-term exposure to fine particulates in the air was linked to a significantly higher risk of Parkinson’s disease in large population groups.
The European Union tracked more than 271,000 people and found higher Parkinson’s death rates in regions with elevated pollution levels, even when those levels were within current regulatory limits.
A 2023 U.S.-based study linked chronic exposure to pollutants such as fine particulate matter (PM2.5), nitrogen dioxide (NO₂), and black carbon with higher rates of Parkinson’s diagnosis, mortality, and hospitalization.
A 2018 study in Rome, however, did not find any connection between air pollution exposure and Parkinson’s disease. Their conclusions: “Incidence of PD was not related to PM exposure in this study, and a negative association was found for nitrogen oxides. The association found with ozone is new and should be further investigated.”
The sources of these pollutants can be linked back to people just trying to make modern life easier, but contaminants, including vehicle exhaust from the transportation we use to get back and forth to our destinations, coal-fired power plants used for electricity, heavy industries, and oil refineries that turn crude into gasoline, heating oil, and plastics. As a result of our society moving towards modernization, we have also released microscopic pollutants into the air that researchers now believe may play a role in increasing the risk of diseases such as Parkinson’s. This study from the BMJ shows that long-term exposure of atmospheric toxins showed significant associations with the incidence of Parkinson’s disease.
Were not breathing Parkinson’s disease, you can’t catch it by taking a breath, but it could be contributing to the potential risk of development based on the amount of pollutants you are exposed to over a period of years. An estimated 5% to 15% of Parkinson’s cases, based on these studies, show an overall risk of developing the disease through long-term exposure to pollutants and particulate matter in the air.
Like a lot of the science in Parkinson’s disease, the environmental effects of Parkinson’s are cumulative over periods of years, which is why it takes so long for the damage caused by air pollution toxins to become apparent to people and in science, often emerging only after decades of exposure.
Since even more researchers are now convinced that Parkinson’s disease is a brain-first or gut-first disease, environmental exposures such as air pollution may play a role in triggering the earliest changes in these systems long before symptoms appear. In combination with exposure from the air we breathe to toxins in our foods from pesticides that have been linked to Parkinson’s, and continue to be legal in the United States, it starts to look less like bad luck and more like the long-term consequences of environmental risks that regulators and governments have often been slow to address, thanks to the influence of industries that wander the halls of the capital building in Washington D.C.
