Noise impacts on health
Any annoying or disturbing noise puts the human body into a state of alert. The body releases stress hormones such as adrenalin and cortisol, the heart beats faster, the blood pressure rises and the respiratory rate increases. This can lead to the following symptoms:
- Impairment of concentration and performance
- Sleep disturbance
- High blood pressure
- Cardiovascular disease
The Swiss population loses around 69,300 years of healthy life (DALYs) each year as a result of traffic noise, with road traffic noise accounting for by far the biggest share.
Most of the DALYs lost are attributable to sleep disturbance (44%) and annoyance (43%). With a share of 13%, ischaemic heart disease caused by traffic noise is of comparatively minor significance.
Despite long-standing efforts to reduce traffic noise, there has been no significant drop in the number of people affected. What's more, the latest WHO study finds that noise is harmful even at low levels. The number of DALYs thus remains consistently high. For this reason, the state is assessed as negative.
The health impacts occur even below the thresholds specified in the Noise Abatement Ordinance (NAO). Measures to reduce traffic noise at the source are therefore all the more important, as such measures benefit everyone
DALYs are an internationally recognised metric for assessing health effects. As well as the health effects of noise, they are also calculated for other health-related environmental impacts such as air pollution. They therefore enable a comparison of the health effects of different environmental burdens.
Direct comparability with other European countries is difficult since these countries have not collected nationwide data on traffic noise as Switzerland has.
The underlying study 'Auswirkungen des Verkehrslärms auf die Gesundheit' (Effects of traffic noise on health) uses the method developed in the study 'Burden of disease from environmental noise: Quantification of healthy life years lost in Europe' (WHO, 2011) and draws on the 'Environmental Noise Guidelines for the European Region' (WHO, 2018).
Taking population exposure to noise as a basis, exposure-response relationships, morbidity and mortality rates are used to calculate how many diseases and deaths are caused by noise. Disability-adjusted life years (DALYs) are the sum of years of life lost due to premature death and 'healthy' life lost due to disease or disability. To calculate DALYs, healthy life lost is also converted into years of life lost by multiplying by a specific percentage value known as the disability weight (DW). The DW reflects how severely a given medical condition affects a person.