How exhaust gases affect the brain

Diesel pollutants in the air we breathe

The scientists exposed 25 healthy adults to air contaminated with diesel engine pollutants for a period of two hours. Before and after the experiment, they assessed the participants’ brain functions in a functional magnetic resonance imaging (fMRI) scanner.

As a control, fMRI images of the participants were taken before and after they breathed filtered air in another test run over a period of two hours.

At the time of the experiment, neither the participants nor the researchers knew whether the air in the test cabin was clean or polluted.

Altered brain function

When comparing the images, the researchers noticed changes in the so-called Default Mode Network (DMN) of the brain after exposure to the pollutant. This is a group of interconnected brain regions that are active during periods of rest, daydreaming, or engaging in introspection. This hibernation network is particularly suitable for detecting deviations in functionality.

The brain functions of the participants returned to normal after a few hours. However, the researchers suspect that the effects of long-term exposure to pollution could also be long-lasting.

Does performance suffer?

That would be very bad news: “We know that altered functional connectivity in the DMN is associated with reduced cognitive performance and symptoms of depression,” explains Dr. Jodie Gawryluk, a psychologist at the University of Victoria and first author of the study “So it’s worrying that traffic pollution is interfering with the same networks,” says the psychologist.

While more research is needed to fully understand the functional impact of these changes, “it’s possible that they affect people’s thinking or ability to work,” says the scientist.

The team is currently investigating such possible effects. “Our first data shows that the reaction time decreases by milliseconds,” explains Prof. Chris Carlsten, head of the research chair in occupational and environmental lung diseases at UBC, when asked by NetDoktor. However, this data has not yet been published.

Protective measures against fine dust & Co.

People should be mindful of the air they breathe and take appropriate steps to minimise their exposure to potentially harmful air pollutants like car exhaust, advises Carlston. For example, you should choose roads and paths with little traffic when you are on foot or by bike. It is also important to ensure that filter systems in the car work effectively. When stuck in traffic, you should leave the windows closed.

Air pollution is a significant health risk

It has long been known that air pollution, especially from traffic, is an enormous health burden: with every breath we take, toxic fine dust gets deep into the lungs and from there into the blood . “We are increasingly seeing effects on all major organ systems,” says Carlsten.

Numerous studies have shown that the risk of cardiovascular and lung diseases increases significantly with increased air pollution. Experts estimate the number of people who die as a result of high levels of air pollution at five million each year.

Via the olfactory bulb into the brain

For a long time, at least the brain was thought to be protected thanks to the blood-brain barrier. In fact, however, apparently tiny pollutant particles can migrate via the olfactory nerves into the olfactory bulb, which sits directly on the frontal lobe of the brain. In animal experiments, researchers have already been able to demonstrate that this is possible. For air pollutants, the structure could thus function as a gateway into the brain.

Another hypothesis is that fine dust circulating in the blood can directly influence the blood-brain barrier in such a way that it becomes more permeable.

More Alzheimer’s sufferers in polluted areas

In fact, various studies are already providing indications of the connection between air pollution and dementia : Where the air is particularly polluted, people develop Alzheimer’s more frequently – and earlier than usual.

However, these are observational studies that show a link, but no evidence that pollution and not another, unknown factor increases the risk of Alzheimer’s.

“Our study provides new evidence for a link between air pollution and cognition,” explains Carlsten. “It’s the first study in the world to show that even brief exposure to air pollution has rapid effects on the brain. Because of its design (randomised, double-blind controlled study) it is unique.”

12 risk factors for dementia

1. This affects the risk of dementia

The genes are to blame! This only applies to a very small proportion of dementia patients. Other risk factors often come into play, above all, of course, age. Some of these can affect you—and thereby reduce your likelihood of mental decline.

2. deafness

When seniors hear worse and worse, their social life suffers. And the brain also bears traces of it: the mental abilities of those affected decrease much faster than their peers who can hear well – by up to 24 percent. The advice of the US researchers who discovered the connection: do not take hearing loss lightly and rather put on a hearing aid early on.

3. Sleeping pills and co.

Drugs for incontinence, sleep disorders or depression seem to increase the risk of dementia in higher doses or over longer periods of time – even after they have been stopped. Researchers advise prescribing anticholinergic drugs at the lowest possible dose, regularly checking the success of the therapy and stopping treatment if the drugs do not have the desired effect.

4. Acid blockers

Acid blockers are often used to treat heartburn. Seniors who took acid blockers like omeprazole and pantoprazole for a long time in one study were 44 percent more likely to develop dementia than those who didn’t take proton pump inhibitors. However, it is still unclear whether the medication or an unknown common factor actually increased the risk of dementia. Either way, the inhibitors should only be taken when absolutely necessary.

5. Vitamin D deficiency

Sunbathing may protect against Alzheimer’s and other dementias. The reason for this: The body forms vitamin D in sunlight. According to a study, people with vitamin D deficiency had a 53 percent increased risk of developing dementia. In the case of a severe shortage, the probability even increased by 125 percent. Vitamin D is also found in some foods, such as fish, but you produce almost 90 percent of what you need yourself.

6. Stress

Divorce, the death of a partner, mentally ill relatives – great mental stress increases the risk of dementia. This applies at least to women, shows a long-term study by the University of Gothenburg. The risk of Alzheimer’s alone increased by 15 percent per stressor. One possible explanation is that stress leads to hormonal changes that negatively affect the central nervous system.

7. Unstable personality

Those who are emotionally less stable, for example particularly nervous, anxious, moody, insecure and sensitive to stress, apparently have a significantly higher risk of Alzheimer’s than emotionally stable people. Psychologists refer to such a trait as neuroticism. Dementia was particularly common in women who were easily stressed and at the same time particularly closed to other people.

8. Loneliness

Being alone and feeling lonely are two different things. Lonely people suffer from being alone. Exactly this feeling is apparently also a risk factor for dementia. In a study with 2,000 participants, those who reported this mental state were 2.5 times more likely to develop dementia later. Timely countermeasures help here, for example by trying to consolidate and expand your social network.

9. Diabetes and hypertension

Diabetes and high blood pressure are bad for the blood vessels. Therefore, diabetics have a higher risk of dementia. And on average, they develop dementia more than two years earlier than non-diabetics. High blood pressure, in turn, increases the risk of so-called vascular dementia, according to a study by the George Institute for Global Health by up to 62 percent if the high blood pressure occurs between the ages of 30 and 50. If, on the other hand, it appears for the first time between the ages of 80 and 90, this even protects.

10. Smoking

Anyone who smokes cigarettes regularly not only damages their lungs and increases their risk of cancer. The brain also suffers because the vessels are narrowed by nicotine and the like. This makes it difficult, among other things, to supply oxygen and nutrients – including in the thinking organ. This in turn can lead to cognitive impairment and ultimately to dementia. Incidentally, many smokers die before they can even develop dementia. Two more good reasons to stop smoking!

11. Air pollution

Dirty air is also suspected of increasing the risk of dementia. A study of older women showed that those who live in urban areas with extremely high levels of air pollution have a 92 percent higher risk of developing dementia than those who live in rural areas with low levels of particulate matter pollution. How exactly the microscopically small particles get into the brain is still unclear, according to the study authors.

12. Weight

Too obese or too skinny – neither is good when it comes to the risk of dementia. However, the researchers disagree when it comes to being slightly overweight in midlife. While some also see the probability increased in this case, other studies even report a protective effect. The answer – and a corresponding recommendation – are still pending here.

13. Depression

Depression and dementia often go hand in hand. That’s why it wasn’t known for a long time whether depression was just a harbinger of dementia or a risk factor. An American study clarified this question in 2014: First comes the mental low, then the mental decline. The following also applies: the stronger the symptoms of depression, the higher the subsequent risk of dementia. According to the experts, anyone who is depressed should definitely be treated for this reason.

14. Healthy lifestyle pays off

Researchers have also found out what you can do to protect yourself from dementia: No cigarettes, no alcohol, a healthy diet, normal weight and exercise – these five lifestyle rules not only strengthen physical but also mental health. The long-term study by Welsh researchers showed that it can actually reduce the likelihood of dementia by up to 60 percent.

In 2020 more than 110 countries committed to a net zero emissions target by 2050, and China, the largest emitter by 2060. Carbon neutrality means some emissions are still being generated but will be offset somewhere else, concluding in net zero emissions. What the Paris Agreement attempts to uphold is making sure global temperatures stay within 2C by 2100, but preferably closer to 1.5C.

In response to the rising cost of living and the nation’s net-zero commitments, Germany started offering monthly public transit tickets for €9 at the start of June. Over 52 million people took advantage of the tickets and the reduction in car use has cut carbon dioxide emissions by 1.8 million tonnes, according to VDV, the leading public-transport organisation in Germany. Additionally, researchers at the University of Potsdam found that air pollution levels fell by up to 7% in response to this shift in German transport use. The ticket scheme expired at the end of August, despite calls for an extension.

The United Arab Emirates (UAE) Net Zero by 2050 strategic initiative is a national drive to achieve net-zero emissions by 2050, making the Emirates the first Middle East and North Africa (MENA) nation to do so. Dubai plans to transform its taxi fleet into 100 per cent eco-friendly vehicles by 2027. All taxis will either be hybrid, electric or hydrogen-powered by the end of the five-year roadmap.

The current study only relied on the fumes of car exhaust, but there may be other forms of air pollution that work even faster and with worse effects. Before leaded Petrol was banned in the United States, for instance, researchers predict the toxic fumes were breathed in by 170 million Americans or more, resulting in a cumulative IQ score loss of 824 million points (nearly 3 points per person).

Petrol might not contain lead today, but that doesn’t mean it’s safe for your lungs, or your brain. “People may want to think twice the next time they’re stuck in traffic with the windows rolled down,” warns Carlsten.

“It’s important to ensure that your car’s air filter is in good working order, and if you’re walking or biking down a busy street, consider diverting to a less busy route.”

For much of the world, however, polluted air is inescapable. We need to know what that is doing to our brains in the long run.

The issue of pollution and smog is just one part of the greater sustainability issue facing the planet and HanseMerkur is trying to do its part and be a good corporate citizen. Click here to find out what we are doing to align capital investments with sustainability.