Is Air Pollution Making Us Less Intelligent?

New, large-scale research confirms that air pollution appears to reduce our cognitive abilities, leading scientists to renew calls for stricter air quality regulation.

The joint effort between US and Chinese researchers, published in “Proceedings of the National Academy of Sciences“, saw scientists collect measurements of sulphur dioxide, nitrogen dioxide and particulate matter in the air around the homes of some 20,000 participants. Those same participants were also given verbal and arithmetic tests to gauge their cognitive abilities throughout the life of the study.

We know that poor air quality can be linked to around 4.2 million deaths every year and may be a key driver of chronic diseases. There is also a significant body of evidence to show links between long term air pollution exposure and conditions like Alzheimer’s, so an impact on cognitive ability isn’t unexpected.

This latest research demonstrated that the longer a person was exposed to toxic air, the worse they performed on cognitive ability tests. What’s perhaps even more interesting is that high levels of air pollution appeared to lead to pronounced falls in a person’s scores even over just a few months. This suggests that when air pollution spikes, our thinking power decreases.

While this kind of link has been made before, this is the first research to break down demographics and look at who might be particularly susceptible to the cognitive decline that results from toxic air exposure.

The research creates a convincing case for the elderly being particularly at risk.

“For older persons (in our study those age 55-65 or 65+) the effects can be very difficult to mitigate given the long term cumulative exposure,” Xi Chen of the Yale School of Public Health told the BBC. “This is very worrisome as we all know that people often have to make important financial decisions in old age, such as when we should retire, which health insurance plan is better.”

The research was conducted with a sample of Chinese nationals, so it doesn’t necessarily translate across the world’s population. However, the study looked at a large-scale sample coupled, and the analysis was able to break down that sample into distinct groups, like age and gender. That means we may be able to draw educated guesses that what is going on in this sample is probably reflective of what is going on in other highly populated areas of the world, like the US.

This study did not establish a direct causal link between particulate matter and chemicals in the air and cognitive decline, but when squared against the existing body of research on this issue, it points to such a link not only existing but being particularly acute for highly populated and polluted areas.

Given that the World Health Organisation believes that over 90 percent of the world’s population now lives in areas where air quality is classed as potentially unsafe, this is concerning. Scientists have repeatedly said that these safety limits are actually too low, which is even more cause for concern.

This is particularly troubling in the US, as the EPA has just rolled back the Clean Air Policy and the Trump administration is seeking to once more take the US all-in on fossil fuel consumption.

While this study cannot directly prove that pollution is leading to a decline in our intelligence, it does heavily hint at this pattern. What’s worse is, as our air quality becomes poorer, it’s likely this effect will worsen, leading to long-term declines in our intelligence.

This begs the question: how long can the Trump administration ignore the scientific reasons why it is a bad idea to ignore air pollution safety limits? Meanwhile, it is the US’s poorest and most vulnerable that are set to suffer thanks to the strong relationship between toxic air exposure and poverty.

Photo credit: Thinkstock.


Irene S
Irene S5 months ago

Most humans seem to live in a highly polluted area.

Val M
Val M5 months ago


Freya H
Freya H5 months ago

Air pollution makes us dumber? No wonder Mensa is having a hard time finding new members.

Gerald L
Gerald L5 months ago

High levels of cellular Lactic acid can cause brain cell death. There is formaldehyde in vehicle exhaust. The Chemical Chain is methanol > formaldehyde > formic acid which metabolizes to Formic acid in the Liver then Lactic acid in all the cells. In a blue baby starved of oxygen it is high levels of Lactic acid that cause the brain cell death.

Margaret G
Margaret Goodman5 months ago

In the United States, the Republican war on public education keeps the United States citizens ignorant. The Republican war on the Clean Air Policy makes the United States citizens stupid. Both of these actions keep Republicans in office, because only the ignorant and/or stupid would vote for Republicans.

JinnySITEISSUES L5 months ago

Polluted minds. That simple and thanks for sharing.

Camilla Vaga
Camilla Vaga5 months ago


Danuta W
Danuta W5 months ago

thanks for sharing

Ruth R
Ruth R5 months ago

Air pollution also has a link to autism. A British study found that the incidence of autism was higher among children living on or near major roads

Shirley S
Shirley S5 months ago

Air pollution causes allergies. Allergies that affect breathing must affect the brain thus making people unable to think straight.