Noise causes stress and is harmful to health. However, whether someone perceives noise as disturbing does not depend solely on the decibel level. A broad variety of other factors such as type of noise, personal attitude, time of day, state of health, age, etc., also play a role. These individual factors can only be reflected to a certain degree in objective exposure limit levels.
In 2013, 32 percent of people felt disturbed or greatly disturbed by traffic noise when at home with an open window, compared with 29 percent in 2012.
Additional measures aimed at reducing exposure to noise are required in towns and cities in particular, since here the proportion of people subjectively exposed to noise is around 37 percent. In view of the potential harm to health and the reduction in the quality of life that go hand in hand with exposure to noise, this figure has to be regarded as much too high.
The data for 2011 are based on the survey entitled "Perception of environmental quality and environmental behaviour" by the Federal Statistical Office (FSO) and the data for 2012 and 2013 on the "UNIVOX Environment" survey, carried out annually by the social research institute gfs-zürich. Both surveys were conducted by telephone on a random sample of the Swiss adult population and include a wide range of aspects regarding environmental pressures, environmental awareness, environment-related behaviour and lifestyle. With a sample of 5129 (FSO) and 1011 (gfs-zürich) people respectively, the surveys can be considered to be largely representative. This indicator includes all those surveyed who felt rather disturbed or greatly disturbed by traffic noise at home with a window open (answers 3 and 4 on a scale of 1: "not at all disturbed" to 5: "greatly disturbed").