Air quality in Oslo

What is the air quality index of Oslo?

Oslo is the capital city of the Scandinavian country of Norway. The metropolitan area of Oslo has a population of approximately 1.7 million people in November 2020.

With regards to air quality, in 2019 Oslo achieved the target figure of less than 10 µg/m³. This is the recommended level as suggested by the World Health Organisation (WHO). This target was attained for 10 months of the year with the other two months bringing in a “Good” reading with figures between 10 and 12 µg/m³. This figure has been fairly static over the two previous years. 2017 saw a 5.2 µg/m³ whilst 2018 showed a figure of 5.5 µg/m³. The average for 2019 was 5.9 µg/m³.

What is the main source of Oslo’s polluted air?

The largest sources of air pollution in Oslo today are road traffic and heating. These sources emit particulate matter (PM2.5 and PM10) and nitrogen dioxide (NO₂). Nitrogen dioxide comes mainly from the exhaust, primarily from diesel-powered vehicles and internal combustion engines that burn fossil fuels, while the main sources of airborne dust are swirling road dust and wood burning.

Locally, building or construction activities or ships and port activities can also make a significant contribution to pollution. In addition, there is pollution that is brought to Oslo by the prevailing winds from other regions and countries.

In areas close to the harbour, ships and harbour activities also contribute to the amount of NO2

Is air pollution in Oslo getting better or worse?

In 2016, the national requirements in the Pollution Control Regulations were tightened. In order to prevent the limit values for local air pollution from being broken, several measures must therefore be initiated. If the limit values are exceeded, Oslo Municipality violates the law. In the last 50 years, air pollution in Oslo has decreased. Local measures have had a good effect, but much remains to be done.

Laws and restrictions set minimum requirements for local air quality. It is the municipalities' responsibility to ensure that these are complied with. The Pollution Control Regulations define minimum requirements for local air quality. The regulations state limit values for, among other things, nitrogen dioxide (NO₂) and particulate matter (PM2.5 and PM10).

For particulate matter, the limit values have largely been complied for Oslo in recent years, both on a daily and annual basis, but in 2016 the requirements in the regulations were tightened. This was because the latest research showed a greater health risk at low concentrations of airborne dust than previously thought. In addition, there are health-based air quality criteria from the National Institute of Public Health and the Norwegian Environment Agency that need to be considered before limits are set.

The air quality criteria are stricter than the limit values in the regulations. The City Council aims to keep local emissions of airborne dust well below the health authorities' recommendations.

A spokesperson from the Urban Environment Agency reported that the measurements show that the annual average levels of nitrogen dioxide (NO₂) in Oslo have decreased in recent years.

This is probably due to a combination of emission reductions, as a result of an increasingly cleaner vehicle fleet and relatively favourable meteorological conditions.

What can be done to improve the air quality in Oslo?

Since 2013, the values for nitrogen dioxide (NO₂) have decreased in Oslo. This applies both along heavily trafficked roads and at measuring stations that are representative of the air quality in Oslo in general. The decline is due to a combination of emission reductions as a result of an increasingly cleaner vehicle fleet and relatively favourable meteorological conditions. Nevertheless, exceedances of the limit value for annual averages are still registered at some measuring stations in heavily trafficked areas, and the concentrations are close to the limit value in several places. The excess is due to the general level of nitrogen dioxide being too high.

The number of exceedances can vary greatly from year to year. The highest levels are measured in the winter due to more stable weather conditions combined with larger emissions, e.g. from a cold start on cars.

In February 2018, the City Council adopted a revised action plan for better air quality in Oslo in 2018-2020. The action plan consisted of over 40 points and contained both immediate measures in the event of high air pollution and general measures for better air. Oslo Municipality has a contingency plan for high air pollution from nitrogen dioxide over larger areas of the city, and with a certain duration. In such situations, immediate measures, such as a total diesel ban, can be implemented if necessary. The general measures include environmental differentiation of vehicles, emission reduction from the port of Oslo, measures for a forced transition to electric vans and measures to reduce emissions from wood burning.

Implemented measures such as changed tariffs in the toll ring, studded tyre fee, cleaning and dust damping and the environmental speed limit have all led to reduced levels of nitrogen dioxide and airborne dust.

More cycle paths, better public transportation, the transition to more environmentally friendly vehicles and emission-free building and construction sites are just some of the focus areas in Oslo Municipality's climate work. It will not only result in lower CO₂ emissions but also less local pollution.

Many households have switched to a more clean-burning and energy-efficient wood stove which helps against airborne dust. Since the municipality established a subsidy scheme for the replacement of wood stoves in 1998, 11,575 old stoves have been replaced at the homes of Oslo residents with support from the municipality.

What are the effects on health through breathing in Oslo’s polluted air?

NOx is the common notation for nitrogen oxide (NO) and nitrogen dioxide (NO₂).

The health effects are primarily related to NO₂. Limit values have therefore been set in the Pollution Control Regulations for this gas. The limit values define a minimum requirement for local air quality. It is the municipalities' responsibility to ensure that these are complied with. Excessive concentrations can be harmful to everyone's health, but children, the elderly and people with respiratory problems are particularly vulnerable.

The main health effects associated with NO₂ exposure are impaired lung function and worsening of asthma and bronchitis.

When nitrogen dioxide levels rise above the limits, many asthma sufferers are self-confined to their homes for long periods of time, especially during the winter months.