The noise coming from Road Traffic it is a huge problem in cities, there is no doubt about that. However, although it has long been known that it is one of the environmental factors that most affects the health of adults, the evidence on its consequences in the little ones is still scarce.
Now, a study in 38 schools in Barcelonawhich was attended by 2,680 boys and girls between seven and ten years of agesuggests that these sounds in schools have a detrimental effect on the development of working memory and attention span of primary school students.
The results of this research, framed in the project BREATHE and led by the Barcelona Institute for Global Health (ISGlobal), a center promoted by the “la Caixa” Foundation, have been published in the magazine PLoS Medicine.
Children who attended schools with more traffic noise had slower cognitive development during that year than those in quieter schools
The team focused on two skills that develop rapidly in preadolescence and are essential for learning and the school performance: the capacity of attention (which makes it possible, among other processes, that we attend to specific stimuli selectively) and the work memory (which allows us to maintain and manipulate information in short periods of time).
“Among the main results, we observed that the boys and girls who went to schools with more traffic noise had a cognitive development slower during that year than those from quieter centres”, he explains to SINC Maria Foreignerfirst author of the work.
On the other hand, within the classroom it was also observed that the most fluctuating traffic noise, that is, with many peaks and valleys, had a greater effect on these cognitive functions. The results are consistent with evidence on the aircraft noise in schoolswhich show that the highest levels affect reading comprehension and hyperactivity.
“These sounds are a side effect of modern life. It is not talked about enough that it is detrimental to health and well-being. It could be said that its influence on the learning of students in schools is the worst damage of environmental noise”, he points out. Trevor CoxProfessor of Acoustic Engineering at the University of Salford (United Kingdom), speaking to the SMC United Kingdom.
“This is because any lack of performance is detrimental to the health and well-being of the rest of the students’ lives. Addressing noise is especially important for equality, because schools in deprived areas are often in noisier places,” he adds.
Twelve months of study
During 2012 and 2013, minors between 6 and 10 years old four times the cognitive tests. The objective of these tests was also to study the evolution of both skills over time. In parallel, noise measurements were carried out both outside the participating schools, as well as in the courtyards and inside the classrooms.
The results show that, after the year of study, the progression of working memory, complex working memory and attention span was slower in male and female students who attended schools with higher traffic noise.
It is not said enough that the sound of traffic is detrimental to health and well-being. Its influence on student learning in schools is arguably the worst harm of environmental noise.
Trevor Cox, University of Salford
For example, a 5dB increment in outside noise levels resulted in 11.4% slower than average working memory development and 23.5% lower complex working memory development. In addition, this exposure translated into a 4.8% slower development of attention span than average.
“Our analysis supports the hypothesis that childhood is a vulnerable period in which external stimuli such as noise can affect the rapid process of cognitive development that takes place before adolescence”, he says Jordi SunyerISGlobal researcher and last author of the study.
Considering that many European children in large cities are exposed to high levels of traffic noise, this study has implications for public policies to reduce traffic noise near schools. Iroise Dumontheilprofessor at the Center for Brain and Cognitive Development at the University of London.
Differences between the interior and exterior of the classroom
In the analysis of external noiseboth a higher average level and a greater fluctuation in the levels in the school were associated with a worse evolution in the results of the student body in all the tests.
Within the classrooms, a greater fluctuation in the noise scale was also associated with a slower evolution over one year in all cognitive tests.
A 5 dB increase in outside noise levels resulted in 11.4% slower than average working memory development and 23.5% slower complex working memory development
In contrast, children exposed to higher mean levels in class during the year only performed worse than students in quieter classes on the test of attention span, but not on tests of working memory.
“This result suggests that noise peaks inside the classroom could be more disruptive for neurodevelopment than the average number of decibels. This is important, because it reinforces the hypothesis that the characteristics of the sound may have more influence than its average levels, when currently the policies are only based on the average decibels”, Foraster points out.
Noise in the home, less influential
The team compared the results with what could happen in the children’s homes. Starting from the road traffic noise map of the city of Barcelona in 2012, the average levels in the home of each participant were estimated. However, in this case no relationship was observed with cognitive development.
“This could be because exposure to noise at school is more damaging because it affects vulnerable windows of concentration and learning processes. In addition, while noise measurements were made in schools, estimates were made in homes that could be less precise and that only reflected the outside, something that could also have influenced the results”, emphasizes the Spanish expert.
One of the most efficient measures would be to reduce this traffic in school settings. In this way, we could protect the health of these children during learning hours
Maria Foraster, author of ISGlobal
More studies needed
The scientific team underlines the need for new studies on road traffic noise in other towns to determine if these first results can be extrapolated to other cities and contexts.
“This is the first study and obviously we will have to do more to confirm these results. But knowing that traffic noise from cars is the most common source of both noise and air pollution, one of the most efficient measures would be to reduce this traffic in school environments. In this way, we could protect the health of these boys and girls during learning hours”, concludes Foraster.
Maria Foraster et al. (2022). ‘Exposure to road traffic noise and cognitive development in schoolchildren in Barcelona, Spain: A population-based cohort study’. PLoS Med.