Qualité de l’air à Stockholm

What is the air quality index of Stockholm?

Stockholm is the capital city of the Scandinavian country, Sweden. A population of over a million people live within its municipality with a further 1.6 million dwelling in the urban area and another 2.4 million in the metropolitan area. The city itself stretches over 14 islands which are located in the Baltic Sea.

At the end of 2020, Stockholm was enjoying “Good” quality air with a US AQI level of just 10. This is based on recommendations from the World Health Organisation (WHO). The concentrations of pollutants which were measured are as follows: PM2.5 - 2.3 µg/m³, PM10 - 4.2 µg/m³ and nitrogen dioxide (NO₂) - 4.4 µg/m³. These are expressed as microns per cubic metre. A micron is one-millionth of a metre so it is extremely small.

With such relatively clean air, it is recommended that doors and windows are opened to let the fresh air into the house and outdoor activities can be enjoyed.

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

Most of the polluted air in Stockholm is generated by vehicle use. One of the city's biggest challenges when it comes to air quality is the high levels of particulate matter PM10 and PM2.5 and nitrogen dioxide (NO₂) on the busiest streets in the city centre.

The production of energy, industry and the operation of machinery, as well as pollution from international shipping, also contribute to Stockholm’s poor air quality.

The use of wood for domestic heating is coming under close scrutiny because it is a veritable source of soot or black carbon (BC). Wood is looked on as a sustainable fuel to take the place of coal and other fossil fuels. Because of this, the use of wood is projected to increase over the next few years, even in developed countries.

Is air pollution in Stockholm getting better or worse?

The long-term trend is that air quality in Stockholm has become much better due to a reduction in the emission levels of many air pollutants.

Tighter controls on emission requirements for vehicles and industries in Europe, expansion of district heating, the phasing in of cleaner fuels and electric cars and the introduction of environmental zones for heavy vehicles are some of the measures introduced by way of reducing air pollution in Stockholm. Coupled with a congestion tax, studded tire ban and dust binding measures have all contributed to a cleaner, healthier environment in the city.

PM10 particles and nitrogen dioxide (NO₂) are the two air pollutants that have the highest levels in Stockholm in comparison with the statutory environmental quality standards. In 2019, the environmental quality standards were met at all measuring stations except one which failed due to too high levels of nitrogen dioxide.

Since 1990, the city's climate impact and greenhouse gas emissions per “Stockholmer” have decreased by 50 per cent. For decades, plans to strategically reduce the city's impact on the climate and the environment have been put into action and it is clearly having a noticeable effect.

Between 2018 and 2019, emissions of nitrogen dioxide (NO₂) from passenger cars decreased by 8 per cent. This was also helped by the introduction of catalytic converters to the exhaust systems of heavy trucks.

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

Over the past few years, lower levels of nitrogen dioxide have been measured at the city's street stations. This is due to the fact that diesel and gasoline-powered cars have decreased at the same time as electric cars and electric hybrid cars have increased. Heavy traffic has also reduced its emissions of nitrogen oxides (NO_x).

PM10 levels have decreased in the inner city because of the increased use of dust-binding agents on roads, especially during the winter months. The reduction is also due to the fact that the use of studded tires has been discouraged and the use has therefore decreased.

In 2016 the Swedish Energy Agency introduced an electric bus premium which aimed to reduce the levels of carbon dioxide by changing the fuel source to non-polluting electricity. Almost 260 buses were approved and it is estimated that this will reduce the levels of carbon dioxide by 181, 000 tons.

Swedish bus manufacturer, Scania is heavily committed to producing more soot-free bus fleets as modern technology advances.

Every car owner can help by keeping their vehicle in good running order and by using premium fuels. Reducing the use of the vehicle, driving at lower speeds and avoid an idling engine are all ways to help lower carbon emissions.

In 2020, Stockholm introduced three levels of low emission zones. Heavy-duty vehicles such as lorries, buses and trucks are to be banned from certain zones. A second zone will only allow vehicles which meet the Euro 5 emission standards whilst the third one will only permit electric, fuel-cell or gas-powered vehicles that meet the Euro 6 standards.

A congestion tax was implemented in Stockholm which had a noticeable effect. The volume of traffic in the city centre was lower by as much as 20 per cent. This, in turn, led to a reduction in ambient air pollution by between 5 and 10 per cent. The knock-on effect of this was that it lowered the rate of severe asthma attacks by as much as 50 per cent.

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

Even young, healthy people can suffer from the effects of being in a polluted environment. But they will not be affected as quickly as those who are suffering from an existing respiratory illness. It also depends on the composition of the content, the concentrations of the pollutants and the length of exposure to it.

Pregnant women, children under the age of 14 years and senior citizens should take extra care.

High levels of air pollution can aggravate cardiovascular and respiratory illness, add stress to the heart which makes it work harder in order to supply the body with the correct levels of oxygen. It can also lead to irreparable damage to cells in the respiratory system.

Premature ageing of the lungs and loss of capacity and function can be a direct result of long-term exposure to poor quality air.