Growing number of Norwegians are exposed to noise

Noise is considered to be pollution under the Norwegian Pollution Control Act (Forurensningsloven). It can cause various health problems and can have a negative impact on people’s well-being. The Norwegian Parliament (Stortinget) has therefore decided to work towards a reduction in noise exposure.

In order to measure noise exposure in Norway, Statistics Norway has calculated how many people are exposed to noise from road, rail and air traffic, as well as manufacturing and other business activities.

Noise is measured as an average level in dB (A) over a 24-hour period. An average noise level of 55 dB (A) is considered to be too high. To put this value into perspective: The noise level on a pavement along an average road in a town can vary between 50 dB (A) background noise and 90 dB (A) when a tipping lorry accelerates.

Road traffic is the largest source of noise

The largest source of noise pollution in 2014 was road traffic, with 1.9 million people affected. Rail and air traffic affected 62 500 and 43 500 people respectively. A total of 53 000 people were exposed to noise from manufacturing and other business activities.

Compared to 1999, the number of people exposed to noise increased for all noise sources, except for rail traffic where the number of affected people decrease by a third.

More noise from road traffic

The number of people exposed to road noise increased between 1999 and 2014 by 54 per cent. Local disparities show that some areas have fewer people affected by noise compared to 1999 and others have more. Cars are generally becoming less noisy due to new technological developments, and are therefore affecting fewer people. However, this development is often outweighed by increasing road traffic and population growth in the most affected areas.

Less noise from rail traffic

Thirty per cent fewer people were exposed to noise from rail traffic in 2014. One reason is the changeover to modern and less noisy trains. Rail traffic has also decreased in many parts of Norway. However, this does not include the east of Norway, especially around Oslo. The increase in rail traffic has a strong effect in these areas, since a large part of the Norwegian population lives here.

Noise from air traffic continues to increase

Twenty-five per cent more people were exposed to air traffic noise in 2014 than in 1999. However, while some airports showed an increase in the number of people affected by noise, other airports showed a decrease or no notable change.

The change to less noisy aeroplanes contributed to a fall in noise exposure at some airports. Nevertheless, the increasing numbers of arrivals and departures at many airports led to more noise exposure at a national level. Changes in the approach path can lead to more houses being exposed to higher noise levels at some airports. The number of people exposed to noise can also increase due to new houses being built in areas affected by noise.

More noise from industries

About 27 400 people were exposed to manufacturing noise in 2014, which is an increase of 6 000 people since 1999. Other business activities affected about 25 300 people; 8 500 more than in 1999. However, it should be noted that these numbers are uncertain.

More people exposed to high indoor noise

Statistics Norway has also calculated how many people were affected by noise levels above 38 dB (A) indoors. This number is to be reduced by 30 per cent by 2020 from 2005 according to the Norwegian Parliament (Report no. 26 to the Stortinget 2006-2007).

About 20 per cent more people were exposed to noise levels above 38 dB (A) inside their homes in 2014. Eighty-nine per cent of these were affected by road traffic noise.

Three times as many people were exposed to indoor noise from rail traffic in 2014 than in 2005. This is mainly due to an increase in rail traffic in and around the capital city of Oslo, which is a very densely populated area. Seventy-five per cent of the people affected lived in Oslo and 20 per cent were in the surrounding county of Akershus.

The increase in people affected by indoor noise from road traffic is caused by the general rise in road traffic and population growth, especially in urban areas with a lot of traffic.

Air traffic is the only source of indoor noise that affects fewer people in 2014 than in 2005, which is mostly due to fewer houses being affected by very high outdoor noise levels.

It has to be noted that the number of people exposed to indoor noise level above 38 dB (A) can be overestimated, but will be more accurate once we have secured more reliable data on noise insulation.

Plans to reduce noise exposure

One reason for the increase in the number of people being exposed to noise is population growth, especially in urban areas. We can also examine the development of noise annoyance without the influence of population growth, which is how the Norwegian parliament assesses noise annoyance.

The Norwegian parliament has decided that noise annoyance is to be reduced by 10 per cent by 2020 compared to 1999. This means that we only take into account the noise exposure at the houses and their residents that were affected by noise in 1999. We calculated the noise annoyance for these houses in 2014 without factoring in the increase in people living in these houses or new houses being built in the relevant areas.

Less annoyance for people that were affected in 1999

The noise annoyance, measured using the noise annoyance index SPI, has decreased by 9 per cent since 1999. That means that the people who were exposed to noise in 1999 are less affected in 2014. SPI decreases by 50 per cent for rail traffic and 30 per cent for air traffic, while road traffic shows only a small decrease.

However, this way of calculating noise exposure has weaknesses. The method does not consider population growth or new houses, nor does it consider new roads or different flight patterns in areas that were not affected in 1999. Moreover, this method does not consider if a road has now more traffic than in 1999 and therefore affects more houses. This explains the disparities between the results for this method and the method where all people that are exposed to a certain noise level are counted, as in the first part of this article.