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Research developments -

In recent years, there have been a number of studies that link air pollution with poor mental health.

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Types of air pollution -

The majority of those studies have focused on urban air pollution, although scientists are now beginning to turn their attention the chemicals found in wildfire smoke.

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Air pollution and depression -

On the one hand, several studies have linked exposure to air pollution with an increased risk of developing depression.

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Study in the US -

In 2023 in the US, for example, there was a study that showed the more people are exposed to a secondary air pollutant called ozone, the more likely they are to develop depression.

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Study in the United Kingdom -

At the same time, a British study found that people who live in areas with high levels of harmful fine particles in the air are at higher risk of depression than people who live in areas where levels are lower.

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Dose response? -

According to John Ioannidis, epidemiologist at Stanford University, it is possible that we have a dose response to air pollution exposure.

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Length of exposure as a factor -

This would mean that our likelihood of developing depression as a result of exposure to dirty air would increase with the length of the exposure.

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The impact of short-term exposure -

However, it is important to note that even a short-term, acute exposure to certain pollutants may be detrimental.

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Air pollution and anxiety -

On the other hand, there are also studies that have linked air pollution with anxiety. One such study was conducted in China in 2017.

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Study in China - The results showed that young people living in areas with the highest fine particle pollution were 29% more likely to develop anxiety than those living in the least polluted areas.

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Air pollution and behavioral problems -

There is even evidence to suggest that less severe mental health issues, such as behavioral problems, are affected by the level of pollution in the air.

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In young children -

According to one study, when the air quality is lower preschool-aged children tend to behave worse.

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In young children -

During the study, deterioration in the children’s behavior meant that they were quicker to break rules and were more likely to act aggressively.

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In adults -

There is also evidence to suggest that adults may behave worse as a result of air pollution.

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In adults -

In 2020, there was a key meta-analysis of multiple studies that showed a link between air pollution and dishonest behaviors, such as cheating on tests.

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Important caveat -

It is important to note, of course, that the majority of the studies linking air pollution and mental health deterioration rely heavily on associations.

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Correlation vs. causation -

That is to say, while there is a correlation between air pollution and mental health issues, that does not necessarily mean there is causation.

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The problem with trials -

The problem with collecting evidence of causation in this context is that it would be unethical to run a randomized control trial.

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Unethical -

Researchers cannot randomly ask one group of study participants to breath polluted air, while the other group breathes clean air.

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Reliance on observational evidence -

As a result, scientists mainly have to rely on observational evidence. Common practice is to take data on air pollution from various areas and match it with rates of anxiety and depression.

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Reason to believe -

Although the evidence is not bulletproof, scientists nonetheless have good reason to believe that air pollution is a contributing factor when it comes to mental health conditions.

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Biological evidence -

Indeed, certain biological mechanisms have been observed in animals that suggest how exactly breathing in dirty air can negatively affect our brains.

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Ozone and dopamine production -

There was one study on rats, for example, that revealed the oxidative stress caused by ozone kills off the brain neurons needed to produce dopamine.

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The pleasure molecule -

Dopamine is the neurotransmitter involved in motivation and reward response. It is often referred to as the ‘pleasure molecule.’

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Attack response -

There was also one study that showed that certain cells in the brain may attack the pollutants found in dirty air.

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Depression-like immune response -

This attack may trigger an immune response from the body of the kind that has previously been linked with depression.

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Implications for humans -

While these mechanisms have not yet been proven in humans, scientists nonetheless believe their existence in animals to be significant.

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Protecting yourself -

If you are worried about how air pollution may be affecting your brain, there are certain steps you can take to protect yourself.

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Protective measures -

If possible, it is best to stay indoors and use an air filter. If you do venture out, aim to wear a mask that effectively prevents you from inhaling the fine particles in the air.

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Protective measures -

Paper masks are usually inadequate; a properly-fitted N95 mask is best. In cases of wildfire smoke, a respirator may be a better option.

Sources: (The Washington Post) (Verywell Mind)

See also: Does air pollution cause dementia?

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