The large volume of vehicle circulation is a problem in the most crowded areas and cities like Barcelona are home to this inconvenience that has a detrimental effect on people's health due to air pollution. One of the negative effects that road traffic brings, noise, is the protagonist of a study in 38 schools in the Catalan capital that has revealed that noise disturbances near schools affect the cognitive development of primary school students.

The study is part of the 'Breathe' project, led by the Barcelona Institute for Global Health (ISGlobal), a center of the 'la Caixa' Foundation, and has been published in the journal Plos Medicine. To do this, researchers Maria Foraster and Jordi Sunyer have evaluated 2,680 boys and girls between the ages of seven and ten and have focused on the possible impact of traffic noise on their attention span, causing them to attend to specific stimuli or focus in specific tasks over a long period of time, and it also affects working memory, which allows us to understand and manipulate information in short periods of time.

The research lasted twelve months between 2012 and 2013 and the results were obtained through four cognitive tests. In addition, the evolution of the students over time was also monitored.

"With the results of the research, we saw that children who go to schools with more traffic noise have a slower development of all cognitive functions consistently compared to their peers who go to spaces with less traffic," he tells ABC. Foraster, one of the promoters of the study. The most disruptive noises, she adds, are "the most fluctuating, with ups and downs mixed with silences, that affect learning the most."

The results, after a year of study, showed that students who attend schools with more noise have a progression of working memory, complex working memory and a slower attention span.

Outside noise from schools, both higher level and higher fluctuation, led to poorer results on all tests. Inside classrooms, a greater fluctuation in noise levels was also associated with a slower progression over a year on cognitive tests. In contrast, students exposed to higher mean levels of classroom noise for a year only performed worse than those in quiet classrooms on the attention span test, but not on the working memory tests.

"If this exposure is consistently maintained over time in the population average, it may be associated with a decrease in cognitive functions and learning, and this could also have a long-term effect in adulthood," says Foraster.

Another parameter that was analyzed in the research was the influence of noise at home. For this, the road traffic noise map of Barcelona in 2012 was taken into account. Even so, a direct relationship between noise in homes and cognitive development was not observed. According to the promoters of the study, this fact is explained by the fact that the most vulnerable period for learning and cognitive development is the moment of concentration that occurs during the hours when children are at school.

With regard to future improvements to this problem, “the most effective short-term solution is to continue with the measures to reduce road traffic, which also help reduce air pollution. In this way, we would be helping to reduce two of the main environmental factors in cities that have a harmful effect on health”, concludes Foraster.