Air pollution has negative repercussions not only on the respiratory tract but also on the brain: Chinese researchers have found that it damages our capacity for reasoning.
Breathing polluted air is equivalent to losing a year of schooling. This is the startling finding of a team of Chinese researchers who, over 14 years, administered mathematics and verbal reasoning tests to more than 20,000 people in 162 counties across China, comparing the results with air pollution data from each location. They found that prolonged exposure to fine particulate matter reduces cognitive abilities, especially with advancing age and in less educated male subjects. According to the scientists, this may be due to the fact that most of them work outdoors.
The study, published in the journal Proceedings of the National Academy of Sciences (Pnas), highlights the major social impact that air pollution could have, given that after the age of 65 people often make important decisions relating to finances and health. However, according to the researchers there are also short-term repercussions, meaning that students' performance could deteriorate when the concentration of fine particulate matter in the air is higher. In particular, an increase of 1 milligram is equivalent to losing one month of schooling.
"Polluted air could cause oxidative stress, neuroinflammation and neurodegenerative diseases," explains Derrick Ho, professor at Hong Kong Polytechnic University, to the British newspaper Guardian. It has already been shown that it increases the mortality rate among people with mental disorders and the onset of mental illness in children. Without doubt, however, further research is needed to confirm the link between exposure to fine particulate matter and cognitive decline, a process that can depend on many factors "such as diet, physical exercise, the stimuli we receive and social interactions," explains James Hendrix, director of scientific initiatives at the Alzheimer's Association.
Pressing ahead with research is crucial when we consider that 9 in 10 people around the world breathe polluted air. In many developing countries, even indoor air is not clean, because wood, coal or manure are burned for cooking and heating. We also know that air pollution causes 7 million deaths a year, of which 91,000 are in Italy.
"Governments really need to take concrete measures to change the situation. The economy will also benefit, given that human capital is one of the most important drivers of growth," said Xi Chen, one of the authors of the study published in Pnas. China is a country full of contradictions: it is the country that pollutes the most, yet the largest investor in the renewable energy sector. If change is not easy, understanding the need for it is the first step towards achieving it.
