More than half of the world’s population now lives in cities. We have to travel in overcrowded areas. The World Health Organization reports that 9 out of 10 people breathe dangerously polluted air.
It is estimated that air pollution causes about seven million deaths per year. Will the murders caused by air pollution be added to these figures soon?
BBC Future reviewed the findings.
First, its effect on exams was investigated.
Researcher Sefi Roth of the London School of Economics was researching the effects of air pollution in 2011. She was aware of the negative health effects, increased hospital admissions, and death rates. “But maybe” she was saying, “it’s affecting our lives in other ways as well.”
He first investigated whether air pollution affects cognitive performance.
Roth and his team evaluated the students who took the exam on different days, as well as measuring the air pollution on those days. All other variables were the same. The education level of the students who took the exam was the same, they took the exam in the same place but on different days.
Roth found that the average of success was surprisingly different. The worst test results were on the days when the air was the most polluted. On days when the air was cleanest, students did better.
“On days with high pollution, performance was clearly degraded,” says Roth. “We didn’t see an effect a few days before or after. But on test day, test results were significantly lower.”
Roth watched 8 to 10 years later to see the long-term effects. Because the exam is so important to students’ further education, those with the worst test scores on days with the highest air pollution were likely to get into lower-ranking universities and earn lower incomes.
“Even if the impact of air pollution is short-lived, if it hits a critical stage in your life, it can have long-term effects,” he says. Another study from 2016 supported Roth’s findings that air pollution can reduce productivity.
Roth analyzed two years of crime data in more than 600 London constituencies in 2018 and determined that the most crimes were committed in both affluent and poor neighborhoods on days when the air was the most polluted.
While making such connections should be discouraged, the researchers found evidence that there may be an occasional cause-and-effect relationship.
Wherever the pollution cloud goes, crime increases.
As part of the same survey, the change over time in specific regions and recorded pollution rates was compared.
After all, a cloud of polluted air can displace as the wind blows and randomly transport the pollution to every part of the city, rich or poor.
“We watched this cloud every day and looked at the crime rates wherever it went. Wherever the cloud went, the crime rate went up,” says Roth.
More importantly, even a little pollution has been shown to make a difference.
“We found that even at levels below current air pollution standards, the impact of pollution on crime is huge,” he says.
In other words, crime rates are high even at pollution levels that the U.S. Environmental Protection Agency calls “good.”
Roth’s studies found no evidence that pollution had a major impact on larger crimes such as murder and rape. But another study from 2018 points to the possibility of such a link.
In the study, chaired by Jackson Lu from the Massachusetts Institute of Technology in the USA, almost the whole of the USA was covered by examining nine years of data in more than 9 thousand cities.
Air pollution was found to predict six main categories of crimes, including homicide, rape, robbery, car theft, theft and assault.
Cities with the highest pollution also had the highest crime rates. This was another correlational study, but it did take into account factors such as population, employment levels, age and gender, and pollution continued to indicate rising crime levels.
Another study of more than 682 teenage teenagers on behaviors such as cheating, truancy, theft, vandalism, and substance use also supported the findings.
Diana Younan of the University of Southern California and her team investigated particles 30 times the width of a hair, called PM2.5, and the cumulative effect of exposure to these particles over 12 years.
Once again, it was seen that where there is more air pollution, bad behavior is also more.
Wanting to make sure the link couldn’t be explained by socioeconomic status alone, Younan’s team sought to separate the impact of microparticles from these other factors known to influence crime, taking into account parental education, poverty, the quality of their neighborhoods, and many other factors.
Noting that an individual’s behavior during adolescence also shows how he or she will behave as an adult, Younan says his findings are particularly worrying for this reason.
Those who engage in delinquent behavior are more likely to fail in school, be unemployed, and become habituated to substance use. Therefore, intervention at a young age is important.
brain inflammation
Exposure to certain pollutants can cause inflammation in the brain.
There are many potential mechanisms that could explain how air pollution affects morality.
For example, Lu showed that the mere thought of pollution can affect human psychology because of its negative connotations.
Researchers naturally could not expose the people they were researching to air pollution. However, both American and Indian participants were shown photos of a highly polluted city and asked to imagine living there.
“We made them feel the effects of the pollution psychologically,” says Lu, “and then we asked them to imagine what they were living there, what their life would be like.”
It was observed that the anxiety of the participants increased and they focused more on themselves. Both of these moods are reactions that can increase aggressive and irresponsible behavior.
“As a self-protection mechanism, we all know that when we’re anxious we’re much more likely to punch someone in the face than when we’re calm,” says Lu.
“Therefore, air pollution can negatively affect behavior by increasing people’s anxiety.”
Experiments showed that participants under ‘dirty conditions’ were more likely to cheat on various tasks assigned to them and exaggerate their performance to get rewards.
This research is just the beginning. Behavioral changes can be caused by many factors other than those mentioned by Lu, including physiological changes in the brain.
When you breathe polluted air, the oxygen rate in your body is affected, which can cause less oxygen to go to the brain.
Polluted air can also irritate the nose and throat, causing headaches. These are all things that reduce the level of concentration.
Exposure to certain pollutants can cause brain inflammation and damage the structure of the brain and nerve connections.
“Air pollutants may be damaging the frontal lobe of the brain,” says Younan. This region is also closely related to impulses, decision-making and self-control.
Damage to this place can not only increase crime rates, but also negatively affect mental health.
A March 2019 study even showed that teens exposed to toxic, polluted air are at higher risk of hearing voices in their head or experiencing psychotic episodes, such as paranoia.
Joanne Newbury of King’s College London, who led the research, says she is not yet in a position to establish a cause-effect relationship, but her findings support studies that show a link between air pollution and mental health.
“Our research supports findings that air pollution is linked to physical health and dementia. Anything that harms the body is expected to harm the brain,” he says.
“Don’t go jogging if it’s dangerous”
Those working in this field emphasize that there should be a greater awareness of the effects of air pollution, whose negative effects on health are now well known.
“We need other studies that show the same thing in other populations and age groups,” Younan says.
Luckily, we can control the amount of pollution we are exposed to every day to some degree.
At any given moment, it is possible to learn about the quality of the air around us. The days with the highest and lowest pollution are monitored. “I wouldn’t recommend going jogging outside or working out indoors if it’s dangerous,” Younan says.
While many countries are waiting for stricter laws or government intervention to reduce pollution, there are those who are taking positive steps.
For example, California is one of them, where regulations reduce pollution and, interestingly, crime.
Although it looks promising, Younan reminds us that we don’t know yet if this is just a coincidence.
In the meantime, in order to create extremely low emission areas by reducing the exhaust gas in London, an additional fee is charged for vehicles entering the city center since April 2019 if they do not comply with the emission standards.
Roth hopes we have control over the increasing air pollution, but it’s also important to raise awareness until a solution is found.
If everyone starts to monitor the level of pollution, it is possible to avoid, for example, exercising outside on the most polluted days, or even commuting.
This benefits both our body, our brain and our behavior.