In France, researchers have discovered a connection between early exposure to road traffic noise and increased emotional and relational challenges in children by the time they reach ten years old. The study, published in The Lancet Public Health in August 2026, analyzed data from more than 8,000 children who were part of the Elfe cohort—a long-term study that has followed these children from birth. The researchers were interested in how different sources of noise in homes might affect children’s emotional and behavioral development, and whether certain periods during childhood are more vulnerable to these effects. Noise pollution is a major public health concern in Europe. According to the European Environment Agency (EEA), it ranks as the second leading environmental cause of health problems, after air pollution. Around 112 million people in Europe—roughly 20% of the population—are exposed to noise levels from transportation that exceed the European safety limit of 55 decibels (dB). For context, normal conversation is about 60 dB, and a vacuum cleaner can reach 70 dB. The study found that children exposed to road traffic noise of at least 60 dB from birth up to the age of 5 and a half were more likely to show internalized symptoms—such as anxiety, withdrawal, and difficulties in relationships—by the time they were 10 and a half. Exposure to noise between 2 months and 5 and a half years also affected children’s social interactions, especially within the family. However, noise exposure later, around age 5 and a half, was more closely linked to externalized issues like hyperactivity and inattention. Researchers explained that constant noise exposure can cause chronic stress, which affects brain development. When exposed to noise, the body reacts as if it is facing a continuous threat, leading to the release of cortisol—a hormone that helps the body respond to stress. Normally, cortisol levels rise temporarily when facing a danger, but in the case of ongoing noise, these levels stay high for long periods, which can disrupt normal development. The study found that only road traffic noise showed this link, not other types of transportation like airplanes or trains. The researchers emphasized the need for better urban planning, lower speed limits, and improved sound insulation to protect children from excessive noise. While the findings are significant, the team plans to conduct further research on larger groups of children to strengthen their conclusions.