We are all surrounded by radiation. Most of this is natural radiation from the sun and from naturally occurring radioactive materials in the bedrock and soil. However, both our own behaviour and industrial activities can increase our exposure to different forms of radiation.

The strength of the UV radiation from the sun varies depending on the time of day, the season, the cloud cover, the thickness of the ozone layer, and reflection from water and snow. Photo: Flickr

After the 1986 Chernobyl accident, Norway received substantial radioactive fallout. Even now, sheep in some parts of the country must be put on a 'clean feeding' regime before they can be slaughtered for food. Photo: Kim Abel, Naturarkivet.no

Radioactivity levels in Norway are generally low. Seaweed, fish and shellfish absorb radioactive substances from seawater, but levels in Norwegian fish and other seafood are so low that there is no health risk. Photo: Bård Bredesen, Naturarkivet.no

Radon in the home accounts for about half of all radiation exposure for the average Norwegian. The authorities recommend measuring radon levels in the home, using a track-etch detector as shown here or an electronic device. Photo: Norwegian Radiation Protection Authority

Measuring radioactive pollution in seawater. Photo: Norwegian Radiation Protection Authority

Ultra-violet radiation

The sun is the most important source of radiation: without it, there would be no life on earth. Sunlight is vital to human health, but can also be harmful. Research has for example shown a relationship between sunbathing and the frequency of skin cancer.

Sunlight consists of a wide spectrum of radiation, including ultra-violet (UV) radiation. Sunbeds and sunlamps also emit UV radiation, and result in much more intense exposure than Norwegian summer sunlight. UV radiation can cause sunburn, skin ageing, damage to the immune system, skin cancer, snow blindness and cataracts. However, in small doses UV radiation has a positive effect, stimulating the production of vitamin D.

The Norwegian Radiation Protection Authority has a nationwide network of measuring stations for UV radiation, and is also responsible for the approval and control of tanning salons in Norway.

Radioactive pollution

There are various sources of radioactive pollution in the Norwegian environment, but levels of radioactive substances are generally low. The Radiation Protection Authority therefore considers radioactive pollution to be of little significance for human health in Norway.

More than 30 years after the Chernobyl disaster, the transfer of radioactive substances from the soil to plants, animals and people is still continuing. To ensure that food is safe, concentrations of caesium-137 are controlled in meat and milk from sheep, cattle and domestic reindeer that graze in areas where fallout was heaviest.

The Norwegian marine areas receive inputs of radioactive substances from several sources. For example, produced water, which always accompanies oil and gas extracted from the reservoirs, contains naturally occurring radioactive substances from the bedrock. Radioactivity in seawater is absorbed by seaweed, fish and shellfish, and people can also receive radiation doses when they eat fish and other seafood. However, people who eat normal amounts of Norwegian seafood receive only low doses of radiation.