In polluted cities around the world, it is becoming increasingly difficult to breathe.
Cars fill streets with exhaust and tiny particles. Smoke from factories and power plants fills the sky. Some days, especially on sunny summer days, particles are transformed into hazardous ozone.
All of this air pollution – smog, soot and ozone – suffocates the lungs of all who breathe it. It also burdens and harms their brains.
According to a recent study published in the Journal Proceedings of the National Academy of Sciences, chronic exposure to air pollution appears to have detrimental effects on perceptions that worsen over the course of life and potentially increase risk factors for degenerative diseases such as dementia and Alzheimer's.
We already knew that life with bad airways is short-lived and bad for children, and harms their developing bodies and brains, according to the authors of the study. But the new study shows for the first time that the effect does not stop, but gets worse with age, with a particularly strong effect on less educated men.
As the authors of the study noted, this could make the end-of-life brain disease trade even more expensive and make older people's care more complicated for society.
Bad air throughout life
For this latest study, the research team examined data from a national survey conducted in 162 randomly selected districts across China between 2010 and 2014 and compared these results with official air quality data.
Using data from several years, the researchers were able to see how particularly polluted times influenced verbal and mathematical test results (hot summer days, for example, tend to be particularly badly polluted). They also saw how life in a polluted area changed test results over time. This cumulative effect was significant.
All in all, the authors of the study found that air pollution puts more pressure on verbal test scores than mathematical scores, although they affect both. It also has a greater effect on men than women. The authors attribute this to the fact that air pollution tends to have a greater impact on areas of the brain that are used in verbal tests, which, according to the authors, are better developed in women in the first place.
If residents of these cities in China lived in places that met US EPA standards for air pollution, the authors estimate that they would significantly improve their test results. To show how much better humans could do, the authors state that these improvements are significant enough to get someone in the median (50th percentile) to 58th percentile in math tests and the 63rd percentile in verbal tests , In the most affected groups, such as the less educated over the age of 64, this change would be even more significant.
China, like many developing countries, has a large number of cities with serious air quality problems. In the study, the authors noted that 98% of cities with more than 100,000 inhabitants in low- and middle-income countries do not meet the World Health Organization's air quality guidelines.
This makes these results applicable to cities with pollution problems around the world.
We know that there are many reasons to worry about air pollution in general, ranging from increased likelihood of lung and heart disease to the fact that air pollution is driving climate change and may have a number of serious health consequences.
But of course, when we talk about the negative effects of bad air, we can not neglect the way this air could change people's ability to think.