More traffic noise, less learning

Noise from road traffic is the most common noise source in European cities today, and many children are exposed to it at school. But what is its effect on their cognitive development? A new study supported by the EU-funded BREATHE and AIR-NB projects has investigated this issue in terms of two abilities that are essential for learning: attention and working memory. The research findings have been published in the journal ‘PLOS Medicine’.According to the study, children exposed to road traffic noise at school show signs of slower attention and working memory development than children attending quieter schools. Attention includes processes such as directing awareness to specific stimuli, focusing on a task for a prolonged period of time, and regulating and monitoring actions. Working memory allows us to maintain and manipulate information over short periods of time. To continuously and effectively process the information held in our working memory, we use what is known as complex working memory.

To obtain these findings, the research team studied a total of 2 680 children 7-10 years of age at 38 schools in Barcelona, Spain. In the course of 1 year, the children completed cognitive tests every 3 months to assess not only their attention and working memory, but also how these evolved over time. During the same year, noise measurements were taken in front of the participating schools, in the playgrounds and inside classrooms.

At the end of the 12-month period, the findings showed that working memory, complex working memory and attention developed more slowly in children attending schools with higher traffic noise levels. Higher levels of outdoor noise and greater fluctuation in noise levels were both linked to worse performance on all cognitive tests. This also applied to greater noise level fluctuation inside the classroom. However, students in classrooms with higher average noise levels throughout the year performed worse than students in quieter classrooms only on the attention test and not on the working memory tests. “This finding suggests that noise peaks inside the classroom may be more disruptive to neurodevelopment than average decibel level,” observes study lead author Assistant Research Prof. Maria Foraster of BREATHE and AIR-NB projects’ host Barcelona Institute for Global Health in a news release posted on ‘ScienceDaily’. “This is important because it supports the hypothesis that noise characteristics may be more influential than average noise levels, despite the fact that current policies are based solely on average decibels.”The researchers also measured average noise levels at each student’s home. Interestingly, they found no association between residential noise and cognitive development. “This could be because noise exposure at school is more detrimental as it affects vulnerable windows of concentration and learning processes,” states Prof. Foraster. “On the other hand, although noise measurements were taken at the schools, noise levels at the children’s homes were estimated using a noise map that may be less accurate and, in any case, only reflected outdoor noise. This, too, may have influenced the results.”

The BREATHE (BRain dEvelopment and Air polluTion ultrafine particles in scHool childrEn) project ended in 2016. AIR-NB (Pre-natal exposure to urban AIR pollution and pre- and post-Natal Brain development) ends in 2023.

For more information, please see:

BREATHE project

AIR-NB project