With plans for a 400m noise barrier that includes solar collectors, the municipality of Lerum is considered to have taken on Sweden’s most interesting environmental project. This is stated in a ranking of Swedish local environmental projects made by the Swedish journal Miljöaktuellt in June 2013.
The NOISUN project is a part of the LIFE+ programme, the EU’s financial instrument to support environment projects throughout the EU. The project’s partners include the municipality of Lerum, SP Technical Research Institute of Sweden, Lerum Fjärrvärme AB and the Swedish Transport Administration.
Lerum, situated in the Gothenburg region, is divided by major thoroughfares for both road and rail traffic, and noise pollution is one of the largest environmental problems in the area. The NOISUN noise barrier will be located in the centre of Lerum.
The E20 motorway is about 50m away from the middle of the barrier and about 3m above the local road, which in turn is about 0.5-1m above the wayside ground. The railway is located between the E20 motorway and the local road, both horizontally and vertically.
The noise barrier will be located between the railway and local road, between 4m and 6m from the nearest railway track. The barrier height is limited to 3m above the railhead, following the regulation of electrical safety and for near track constructions. According to the noise calculations, the barrier noise reduction is over 10dB for the railway noise while only about 4-5dB for the E20 motorway noise (because of the long distance).
A questionnaire study has been conducted in order to identify the current noise situation in the residential area before having the noise barrier protection, both measured and perceived. This study is targeted to investigate the perceived noise impact.
The result of the study will be used in planning the barrier, and a follow up questionnaire targeted to identify the noise situation after the noise barrier is erected will be circulated.
At the noise-exposed area there are different types of buildings – e.g. apartment buildings, terraced and detached houses, with approximately 680 residents. The selection was made by choosing an adult in each household to answer the questionnaire.
Each of the respondents were asked to provide information about themselves, such as gender, age, working hours, the number of people in the household and number of years of residency in the area. The questions addressed the perceived existing noise situation, e.g. annoyance by noise from road, rail, air traffic.
The questionnaire was posed to 369 people, of which 280 responded, representing a response rate of 76%. The most important noise sources in the residential area are the rail and road traffic, with the next most important source being noise from neighbours.
In the studied residential area, around 68.5% of the residents do not have access to a quiet room in their flat/house where they do not notice road or rail traffic noise, even with the window ajar. About 81.5% of the residents do not have access to a quiet place outdoors adjacent to their flat/house where they do not notice road or rail traffic noise. These two figures indicate the demands to reduce noise from the rail and road traffic.
As a result of this, the creation of a barrier to reduce noise from the rail and road traffic will, to a large extent, diminish the impact of environmental noise in the studied residential area. And, it should also be highlighted that some of the noise which stems from the local road will not be reduced by the noise barrier because it is located behind the barrier.