People who are exposed to high levels of noise pollution are more likely to suffer from health problems such as sleep deprivation and stress. This is one of the findings of De Oorzaak, the largest citizen survey on environmental noise ever conducted. The results are explained in detail in a dossier in De Morgen and at final symposiums in Antwerp, Leuven and Ghent. ‘Hopefully, De Oorzaak will have a positive effect on noise policy in our society.’
At the end of 2023, De Oorzaak ('The Cause') launched the largest citizen survey on environmental noise in Flanders. The University of Antwerp, the UZA and De Morgen joined forces for this project. The ambitious goal? To map out in detail the sounds we hear every day, which sounds are the loudest and what effect they have on our health. To this end, De Oorzaak got help of thousands of citizen scientists.
Two years later, the results are in. They are based on an impressive amount of collected data: 4,665 Flemish people took part in a Sound Walk, 10,138 people completed the Great Sound Survey, and innovative sound sensors recorded all environmental sounds at 1,452 locations in Antwerp, Ghent and Leuven over a period of six weeks. In addition, 101 Antwerp residents underwent sleep and hearing tests, and 128 citizen scientists shared data from their Apple Watches.
Traffic noise affects quality of life
The unique AI-driven model mapped the noise sources. The noise was divided into nine different classes: from people and animals to all types of traffic-related noise.
‘Road traffic is the dominant source of noise pollution,’ says Cedric Vuye (UAntwerp), lead researcher at De Oorzaak. ‘In Antwerp, Ghent and Leuven, we measure noise levels that are often higher than the thresholds proposed by the researchers: 60 decibels (dBA) for the average noise level over a whole day, evening and night, and 50 dBA as a guideline value for the night.’
'On the street side, the noise level exceeds 60 dBA in 44% of cases. At night, we see that the threshold of 50 dBA is exceeded in almost half of the cases. This shows that traffic noise is a structural challenge in urban environments. There is also a strong link between noise pollution and reported health problems: sleep, stress, fatigue, etc. People in Antwerp report more nuisance than people in Ghent and Leuven.'
Approximately three in ten participants were found to have elevated scores for hyperacusis, or sound sensitivity. This group reported significantly more discomfort and stress from environmental noise than average. Saliva analyses of a subgroup of Antwerp participants in the UZA health study also showed that people with hyperacusis have higher cortisol levels, a biological indicator of increased stress. ‘Hyperacusis shows that sound does not have the same impact on everyone,’ says audiologist Laure Jacquemin (UZA/UAntwerp). ‘For people with increased sensitivity, noise not only amplifies the subjective discomfort, but also the physical stress response.’
Is tinnitus permanent?
Prolonged exposure to noise can, in some cases, lead to tinnitus. Many people believe that there is no cure for this ringing sound. But that is not the case, according to Laure Jacquemin, clinical audiologist and post-doctoral researcher into tinnitus.
Noise pollution also a matter of social inequality
The analyses show that noise pollution does not affect everyone equally. Residents of flats or studios and lower-income households in particular report significantly more nuisance. These socio-demographic differences show that noise pollution is not only an environmental problem, but also an issue of social inequality.
Although the results point to the negative impact of traffic noise, they also convey a hopeful message. All surveys and measurements show that nature sounds are systematically perceived as positive. Hearing birds singing, leaves rustling or water flowing not only creates more peace and quiet, but is also associated with less stress and nuisance. Participants who noticed nature sounds more often reported higher satisfaction with their living environment.
T'he effect of nature sounds is remarkably consistent,' says Jonas Lembrechts (UAntwerp). ‘Even in urban contexts where traffic noise dominates, we see that adding nature – parks, trees, courtyard gardens – measurably improves the soundscape. It confirms that investing in more green and quiet zones is not only ecologically or aesthetically valuable, but also directly contributes to health and well-being.’
Curious for the results?
With De Oorzaak, the University of Antwerp, De Morgen and the UZA are mapping noise and noise pollution in Flanders with the help of thousands of citizen scientists.