We all know that traffic noise can be annoying, but did you know that it can also affect your cognitive performance and health? A new study from Chalmers University of Technology in Sweden shows that even weak traffic noise, as low as 40 decibels (dB), can impair your concentration and make you feel more stressed. This is the typical level of background noise in an office environment or a kitchen.
The researchers conducted a laboratory study where test subjects performed concentration tests while being exposed to background traffic noise. The subjects were asked to look at a computer screen and react to certain letters, then to assess their perceived workload afterwards. The study shows that the subjects had significantly poorer results on the performance test, and also felt that the task was more difficult to carry out, with traffic noise in the background.
“What is unique about our study is that we were able to demonstrate a decline in performance at noise levels as low as 40 dB, which corresponds to the regular noise level in an office environment or a kitchen,” says Leon Müller, doctoral student at the Division of Applied Acoustics in the Department of Architecture and Civil Engineering.
The background noise consisted of two audio sequences simulating trucks passing by at a distance of ten and fifty meters. Both sequences were normalized to the same total indoor level of 40 dB.
“The audio sequence simulating the closer passages, where the sound changes significantly as the vehicle passes by, was usually the one that bothered the test subjects the most,” Müller says. “This could be because traffic that is further away is perceived as a more constant drone.”
The study suggests that traffic noise can affect cognitive performance and health, and that current regulations do not adequately protect people from low-frequency noise indoors. Low-frequency noise is primarily generated by heavy traffic at low speeds, and is difficult to shut out even with well-insulated windows and buildings.
According to Jens Forssén, professor of applied acoustics at Chalmers, low-frequency noise can have more disruptive and harmful effects on human health than higher-frequency noise. “Low-frequency noise can cause annoyance, sleep disturbance, cardiovascular disease and cognitive impairment,” he says.
Other studies have also linked traffic noise to increased risk of dementia, depression and anxiety. A recent study from the University of Oxford found that people living in areas with high levels of road traffic noise had a 27% higher risk of developing dementia than those living in quieter areas.
“Noise pollution is a major public health issue that affects millions of people worldwide,” says Dr. Thomas Littlejohns, senior author of the Oxford study. “Our findings suggest that reducing exposure to road traffic noise could also reduce the incidence of dementia.”
The researchers recommend that people take measures to reduce their exposure to traffic noise, such as using earplugs, headphones or white noise machines. They also urge policymakers and urban planners to consider the impact of traffic noise on human health and well-being when designing new buildings and roads.
“Traffic noise is a silent threat that we need to take seriously,” says Müller. “We hope that our study will raise awareness and inspire action to create healthier and quieter environments for everyone.”