Traffic-Related Air Pollution May Promote Neurological Diseases

A new study claims that pollution in the air may contribute to the risk of dementia at an older age. The research shows the effects of air pollution on wild rats. These rats developed the characteristics of Alzheimer’s disease due to air pollution caused by traffic.

Thus, the findings of the study support the claim of developing Alzheimer’s because of air pollution.

According to a recent report from WHO (World Health Organization), nearly 50 million people worldwide are patients of dementia.

The post from Medical News Today discusses how pollution is increasing Dementia risks.

Dementia and Alzheimer’s Disease

Dementia and Alzheimer’s disease are neurological disorders that damage the cognitive ability of a patient. 

They are yet not reversible. Besides, they progress with age and induce problems like memory loss and the loss of cognitive ability are the common damages done by these diseases.  

More than 70% of dementia patients experience cognitive decline as they age. It has been a highly developing mental disorder for a few decades. 

Unfortunately, there is no cure and treatments available to reverse the symptoms. However, the researchers are experimenting with new ways to decelerate the progression and worsening of the symptoms.

The scientists from the University of California have suggested that air pollution may contribute to the development of dementia. Similarly, the risk of developing Alzheimer’s also increases because of highly polluted air.

The Environmental Health Perspective Journal has published the study conducted on TGF344-AD rats. They settled the rats in a rodent vivarium near a densely trafficked area. So, they selected a tunnel in northern California for this purpose.

Since the tunnel was well-used for traffic, there was more significant exposure to traffic-related air pollution for those rodents.

Davis explained the significant efforts for the study. A neurotoxicology professor at the University of California and the senior author of the study, Dr. Pamela Lein, talks about the study.

She says that there was a need for experimental animal study in this domain because there was no evidence to confirm the cause-effect relationship of exposure to pollution and improved symptoms of dementia.

Study Limitations

Dr. Pamela believes that the study will surely help students understand the association between the cause and effect of traffic-related air pollution.

However, there are some limitations as well. The data is based on the study of the animals. So, the results may vary for humans. 

Secondly, the rodents were exposed to the highly concentrated condition of traffic-related pollution, more likely for the shorter periods.

On the other hand, the study may provide strong evidence to prove the adverse outcomes of air pollution caused by traffic. 

Moreover, it will help to understand the distribution of neurological disease in the human population. According to Pamela Lein, it will also help figure out the factors that trigger some specific conditions.


To experiment with the effect of air pollution, the team exposed the rats to filtered and polluted air for more than a year. For that, they delivered highly polluted air directly to rats by drawing the air into the tunnel.

They divided the rats into two separate groups. In the first group, they kept TGF344-AD rats. These rats possess genes that are considered helpful for Alzheimer’s disease in humans as well. At the same time, the second group consisted of wild rats.

Furthermore, the age of the rates ranged from 3 to 15 months. They monitored whether the rats express symptoms of Alzheimer’s disease. They analyzed the characteristics of the disease by using behavioral testing and hyperspectral imaging techniques.


Exposure to the highly dense air pollution caused by chronic traffic brought surprising changes in the rats—those who had the genetic capability of developing Alzheimer’s expressed acceleration in the development of disease.

Interestingly, the wild rats showed the same trait of developing Alzheimer’s.


Dr. Lein said that exposure to traffic-related air pollution accelerates the development of Alzheimer’s. Besides, it heightened the intensity of disease in those already at genetic risk of Alzheimer’s.

However, the clinical profile and medical history may vary in people with comparable genetic risk of Alzheimer’s. This can happen due to the difference in exposure to the leading causes.

Lein says that people having no genetic risk of Alzheimer’s are not safe either. Perhaps, they can also face similar consequences of intense traffic-related air pollution if they experience chronic traffic.

Additional Research Needed

The Vice President of Medical Relations at the Alzheimer’s Association, Dr. Heather Synder, shared her reviews with MNT. She was obliged to see the interest of these researchers to develop an understanding of Alzheimer’s disease. 

According to Heather, their curiosity to unfold the mechanisms behind the quicker onset of the disease is remarkable.

But the claim needs more research to interpret these findings on humans. Neurological disorders like Alzheimer’s, dementia, and many more are very complicated yet complex issues. 

Yet, many factors contribute to the development and progression of these diseases.

Dr. Lein said that the claim brings out many questions. For example;

  • Either the gasses or particulate matter which is responsible for this pollution?
  • Which mechanisms of traffic-related air pollution are highly contributing to mental disorders?
  • What parts from light-duty and heavy-duty vehicles play a vital role in promoting Alzheimer’s disease phenotypes?   

Dr. Lein and her team eagerly want to find out the answers to these queries. Besides, they are looking forward to finding out other outcomes or traffic-related air pollution.

Age and the duration of the exposure to chronic traffic conditions can be other factors that may affect the brain. According to Lein;

  • Is exposure to chronic traffic and air pollution at an early age a factor in the onset of Alzheimer’s disease?
  • Can early life exposure affect the brain at an older age?
  • What duration of the disclosure can trigger the progression of mental disorders?
  • Does it require a lifetime exposure to develop such complex diseases?

Lein says that some many queries and uncertainties make the significance of the study questionable. Thus, she is eager to conduct more research in this domain to improve the importance of her findings.

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Bottom Line

The motto of the study was to address the environmental factors for critical mental disorders. Because these factors slowly and gradually contribute to the progression of diseases like Alzheimer’s and dementia, unnoticeably. Adding more, these factors are easy to understand, unlike genetic factors.

However, the information needs more research, it is yet to be helpful in lawmaking. As Dr. Lein says, addressing these environmental causes of such chronic diseases may guide policymaking.

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