Recommended noise limits
In spatial planning, the authorities designate a noise zone around roads, railroads, industries, and other noise sources, where the noise level exceeds the recommended noise limit.
The Danish Environmental Protection Agency has published recommended noise limits for most types of environmental noise. As a general rule, the recommended noise limits are based on the perception of noise, found by research where large groups of people are interviewed.
Types of noise
Different types of noise are not equally annoying, aircraft noise is found to annoy more than road traffic, and train noise is the least annoying. This is illustrated in the Figure below (based on data from Miedema, H.M.E.: "Annoyance from transportation noise: relationship with exposure metrics DNL and DENL and their confidence intervals", Environmental Health Perspectives 109 (6) 2001 p. 409-416).
The recommended noise limits express an acceptable noise impact both environmentally and health wise. The limits are subject to a trade-off between the effects of noise on people and economic/political considerations. Typically 10 – 15% of the population is highly annoyed when noise is as high as the recommended limit. When the noise is below the recommended limit, less people are annoyed, and no health effects are to be expected.
Recommended noise limits - the basis for assessment of noise pollution
The recommended noise limits form the basis for the authorities' assessment of noise impact. They are published in the form of guidelines, and in actual cases the authorities can relax or tighten the limits in consideration of specific individual matters. The recommended noise limits neither represent a right for an industry to emit noise, nor a right for neighbours to avoid noise from a plant.
In spatial planning, the authorities designate a noise zone around roads, railroads, industries, and other noise sources, where the noise level exceeds the recommended noise limit. According to the Act on Spatial Planning (in Danish), noise impacted areas must not be planned for noise sensitive use (such as dwellings or institutions with overnight accommodation), unless the plan includes means to reduce the noise.
When the environmental authorities grant an environmental permit to a plant, they use the recommended noise limits, as well as a description of the noise level that can be obtained by use of the best available technology, as a basis for the specific noise limits in the conditions of the permit. The noise limits specify the noise level in the surroundings, the plant may cause, and they are binding for the plant.
Recommended noise limits for injunction and strategic noise reduction
When people complain about annoying noise from a plant, an industry, or an installation, not having an environmental permit, the authorities use the recommended noise limits as the basis for evaluation of the actual noise impact. The authorities can raise a ban about noise reduction, which may include specific noise limits.
When deciding which limits to set in actual cases, the authorities consider both the recommended noise limits and the practical and economical possibilities to reduce the noise. This type of regulation applies to workshops, shops, construction activities, restaurants, sports centres, recreation centres, etc., but cannot be used in regards to noise produced by private individuals or from road or rail traffic.
Finally, the recommended noise limits are used in strategic planning; when the number of noise impacted people due to a new project or plan is researched, or in connection with municipal noise action plans.
Read more about the noise zones