Tromsø is a municipality in Troms County in Northern Norway located 350 kilometres north of the arctic circle, at 69 degrees North, the same latitude as Siberia and northern Alaska. It covers a rather large geographical area (2,521 square kilometres) and is the largest urban area in the region. The majority lives quite concentrated in Tromsø city centre and suburbs close by, and only 20% lives in rural areas. It develops on two main islands, Tromsøya and Kvaløya, the mainland and some other islands. Tromsø is the administrative centre of Troms County.

Tromsø is the ninth largest municipality in Norway in terms of population and the largest municipality in North Norway. It has a population of ethnic Norwegians, Sami and Kven people, and it includes a growing immigrant and international population from 138 different countries and adds rich variation to the municipality context.

The population is exposed to a climate with frequent changes in weather conditions and extreme variations in daylight exposure. The sun is below the horizon from mid-November to mid-January and does not set between mid-May and mid-July giving Tromsø a dark winter season and a summer season with 24-hour daylight.

  • Population

    According to the national statistics, Tromsø has 78,372 inhabitants (3rd quarter 2023).

    The largest employers are The Arctic University of Norway, the University Hospital of North Norway, Tromsø municipality and Troms County. Tromsø also is a fishing municipality, with both fishing and aquaculture. It has an important seaport that allows for a considerable fish trade which is a significant part of the local economy, with companies engaged in both fishing and fish processing. Tromsø has Norway’s major Arctic fishery, sealing, and shipping facilities, and local industry deals mainly with storing and processing fish.

    Advanced expertise and technology are also found within fields such as information and communication technologies (ICT), arctic science and life sciences. Scientific research is a significant part of Tromsø's economy, with many Arctic-related research institutions and organisations. In recent years, the tourism industry has become more and more important, especially due to the opportunity to observe the Northern Lights, the midnight sun, and the beautiful nature.

    Educational attainment has been increasing in Norway, in particular at tertiary level, as reported by OECD indicators. Between 2000 and 2021, the share of 25–34-year-olds with tertiary attainment increased from 35% in 2000 to 56.4% in 2022.

    In the age group 45 years and older, the proportion of people living alone is higher than in the country as a whole. The proportion of children living in households with persistently low income is lower than in the country as a whole. Persistently low household income means that the average income in a three-year period is below 60% of the median household income in Norway.

    The proportion of upper secondary school students who report high life satisfaction is not significantly different from the national level. The proportion includes those who answer 8 or higher on a scale of 0-10, where 0 is the worst possible life, they can imagine and 10 the best possible. The figures are taken from the Ungdata survey.

    According to Statistics Norway, the average yearly earnings in the country is set at 634,700 Norwegian Kroner. At national level, the unemployment rate is 3.5% in 2023, and the number of employed people aged 15-74 is 2,889,000 out of the 5.5M population currently living in Norway. The unemployment rate in Troms County is 1.5% and in Tromsø municipality 1.1% as of October 2023.


Relevant environmental risk factors that the municipality is exposed to are ultraviolet rays and polluting particles in the air. Moreover, other risk factors can be found in other abiotic factors such as the temperature.

  • What is ultraviolet radiation?

    UV indicates the intensity of the sun on the Earth's surface. According to the World Health Organization (WHO), small doses of UV rays are necessary for human beings since they allow us to produce vitamin D, one of the main substances that strengthen our bones. However, excessive exposure is directly related to harmful effects on our health.

    Knowing the difference between UVA and UVB rays is vital. UVB causes immediate harm like burns, while UVA leads to long-term issues like premature ageing and a higher risk of skin cancer.

    In addition, the WHO confirms that the chronic effects of UV rays not only depend on the doses but also on the individual sensibility, making it determinant in some cases.

    Radiation level: UV index

    The intensity of UV rays is measured as the solar UV index or solar index. The solar index is related to a daily maximum, a value that will indicate the higher or lower risk of harm from the sun, depending on our location and the moment in time during which we are exposed. This UV index varies throughout the day being at its peak at midday.

    The values of the UV index established by WHO are classified as low, moderate, high, very high, and extreme exposure:

    Exposure category
    UV values

    The UV index in Tromsø, Norway, varies throughout the year. Despite the subarctic climate that characterizes the municipality, in summer months (June-August) the UV index can reach higher levels (5-7). This indicates moderate to high risk of harm from unprotected sun exposure. The extended daylight hours during this period allow people to enjoy outdoor activities even late at night, which may result in increased sunlight exposure, making it essential to protect skin from harmful UV rays. On the other hand, from mid-November to mid-January, the sun does not rise above the horizon, and in this period, there is UV index of 0 and no risk of sunburn.

    Although the sun is not seen very often, Norway reports a high incidence of melanoma (source). Having a shorter summer season than many other EU countries, excessive sun exposure is in fact more common when the opportunity arrives. In addition, a significant part of the population in Norway has light skin.

    Health Risk Factors

    UV rays can trigger the development of non-communicable diseases, in particular skin cancer and melanoma in Europe. Numerous investigations made by organizations such as the European Academy of Dermatology and Venereology (EAVD) and the World Health Organization (WHO) highlight the relationship between UV rays’ exposure and the risk of suffering from such diseases.

    According to the WHO, UV leads to 1.5 million cases of skin cancer every year across the world, and this trend has been rising in various European countries in recent years. Skin melanoma accounted for 4% of all new cancer diagnoses in EU-27 countries in 2020 (all cancers, excluding non-melanoma skin cancers) and for 1.3% of all deaths due to cancer.

    Norway has the third highest incidence of melanoma in Europe, after Denmark and the Netherlands, and the highest mortality from melanoma. Over 2,000 people are diagnosed with melanoma every year in Norway and 300 deaths are attributed to melanoma. As reported in the Cancer in Norway 2022 Report, published by the Cancer Registry of Norway, in Tromsø the average annual number of new skin melanoma cases is 43 in male population and 42 in the female population.

    In recent years, the European Commission has played a relevant role in actively promoting campaigns for solar security that encourage the use of sunscreens with an appropriate sun protection factor (SPF), the use of protective clothes and looking for shade during peak hours and emphasizing the importance of periodic cutaneous revisions. By knowing the implications of UV rays’ exposure and adopting preventive strategies, people can protect their skin and reduce the risk of non-communicable diseases in Europe.

    There are various categories to classify skin types in relation to their reaction to UV rays. One of the most prevalent classifications was made by Dr. Fitzpatrick from Harvard Medical School in 1975. This classification - commonly called the Fitzpatrick scale - is based on different physical characteristics like sun sensibility, skin tone, hair, and eye colour. The system entails a scale of six different skin types (or phototypes), each of those can be linked to specific ethnic groups.

    Skin types
    Skin types
    Skin types
    White skin, alabasters with lots of freckles and blond.
    Always gets burnt easily and the burns can be intense. Never gets a tan.
    White skin, blue eyes.
    Always gets burnt easily, and the burn can be intense. Can get slightly tan.
    White skin with a slightly brown tone. Caucasian.
    Can get burnt, the burn would be moderate. Can get gradually tan.
    Brown skin is more or less intense. Mediterranean.
    Can get burnt but it would be minimal. Always gets tan.
    Intense brown skin. Asians, People of colour with a less intense skin colour, Middle East and South America.
    Rarely gets burnt. Gets easily tan.
    Intense black skin.
    Never gets burnt. Gets tan more easily.

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  • In this section, we present information about diverse environmental factors such as water quality, temperatures, and midnight sun i.e., the consecutive 24-hour periods of sunlight experienced north of the Arctic Circle including in Tromsø. This information is relevant because of its impact on our well-being.

    Water quality is essential to prevent the spread of diseases through water and guarantee safe hydration for people. Temperature directly influences our comfort and health since prolonged exposure to extreme temperatures can lead to heat stroke, hypothermia, or worsen existing medical conditions. Finally, midnight sun in summer and prolonged darkness in winter may affect citizens' daily lives and well-being.

    Water for consumption

    Tap water is considered safe to drink all over Norway, including in the municipality of Tromsø. Norway ranks second in having the best, highest-quality tap water worldwide, protecting the groundwater and utilizing advanced systems to guarantee a good quality for the citizens.

    The government collects samples from hundreds of waterworks to analyse the water treatment methods. The waterworks supply a good portion of the Norwegian population. The Norwegian Food Safety Authority has registered 1,500 waterwork plants in Norway.

    The water hardness may vary in certain areas, but the largest parts of the country have soft water following through their pipes. Soft water translates to having lower amounts of minerals like calcium and magnesium, thus improving the taste and the quality of drinking water.

    Although the water quality is generally good, the Norwegian Institute of Public Health in a public report on drinking water points out that a part of the pipeline system, where water supplies are, is rather old and vulnerable. Since the drinking water pipeline usually lies in the same ditch as the drainage pipeline, which may also leak, there is a risk of contamination during leakage or repairs. The rate of replacement and repair of poor pipelines is rather slow, so that the problem of contaminated drinking water is likely to increase in years to come. In addition, large amounts of precipitation, flooding and landslides as a result of climate change could increase the risk of damage to pipelines.



    Tromsø is characterised by a subarctic climate, with very cold winters and cool summers. The influence of the sea and the Gulf Stream is however felt, so that temperatures in winter do not reach too low values, at least when considering the latitude. On the coldest nights of the year, it typically drops to around -14 °C, and the coldest record is -20 °C.

    In return, snowfalls are frequent and sometimes abundant. Indeed, Tromsø is very snowy. The maximum snow depth is especially reached in April. There are also periods when the temperature exceeds freezing, the snow melts, at least partially, and rain falls instead of snow. However, a strong wind can blow during these times.

    The summer is cool, usually with frequent rains, but there are also some pleasant periods with temperatures attaining 18-20℃. In recent summer periods, Tromsø has experienced higher temperatures, reaching even 30℃. This is primarily due to global warming, which, according to WHO, has become a worldwide health threat of the 21st century.

    Extremes of temperature - both heat and cold – have the potential to worsen pre-existing health conditions, particularly impacting vascular and respiratory issues. For instance, outcomes of a study analysing the impact of external weather changes on chronic pulmonary infection in South Norway highlights the dependence between air temperatures and the patients' condition.

    In particular, winter months with cold temperatures have an impact on lung function and the risk of exacerbations. For instance, many patients with COPD attest that colder temperatures can make symptoms worse due to an increased strain on the respiratory system. Cold and flu viruses can also make COPD symptoms worse.

    Midnight sun and polar night

    The ‘Midnight Sun’ is a natural phenomenon that occurs north of the Arctic Circle and south of the Antarctic Circle. Since the axial tilt of Earth is considerable, during a specific period of time the sun does not set, resulting in 24 hours of daylight. This is a phenomenon that characterizes the municipality of Tromsø.

    aurora boreal

    A case study from Tromsø focusing on sleep in the land of the midnight sun and polar night found some evidence of monthly or seasonal variation in sleep problems. Insomnia was most common during the winter months among men, but not women. No seasonal or monthly effects were observed for sleep duration. The small or non-existing seasonal variation in sleep and sleep difficulties indicate that extreme seasonal variation in daylight is of little influence on sleep status. Tromsø is a modern municipality with a considerable level of artificial light, which may contribute to the observed rather stable sleep patterns throughout the year.

    Similarly, another study in Tromsø investigated the potential negative impact of winter darkness on mental distress and sleeping problems. The study found no significant differences in the reporting of current mental distress depending on season. Significantly more reported current sleeping problems in winter than in the other seasons, and less sleeping problems was found in spring.

    Although it is true that living in Tromsø and in the Arctic in general, where the phenomenon of 'midnight sun' occurs, does not inherently increase the probability of diseases compared to other regions, the relationship between geographical location and health outcomes is typically associated with a complex interplay of factors, including genetics, lifestyle, access to healthcare, environmental conditions, and socioeconomic variables.

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