Air quality in Sweden

What is the air quality forecast for Sweden?

Sweden is officially known as the Kingdom of Sweden and is a Nordic country situated in northern Europe. With a land area of 450,295 square kilometres, it is the largest country in northern Europe. Its capital city of Stockholm has a population of approximately 10.5 million people at the end of 2020.

In 2019 Sweden enjoyed high-quality air and easily achieved the World Health Organisation’s (WHO) target figure of 10 µg/m³ with their measurement of 6.1 µg/m³. The target figure was achieved for 11 months of the year with just April showing higher levels at 11.3 µg/m³. Even though, this can still be classified as “Good” with a figure from 10 to 12 µg/m³. Looking back over their historical figures, the quality of air in Sweden remains roughly the same. In 2017 the average was 4.4 µg/m³ and in 2018 it was 6.6 µg/m³.

What is the current state of air pollution in Sweden?

Every year, the Swedish Environmental Protection Agency compiles data on Sweden's emissions of air pollutants. Emissions of sulphur dioxide (SO₂), nitrogen oxides (NO_x), volatile organic compounds (VOC)s, particulate matter (PM2.5 and PM10) and heavy metals have fallen sharply since 1990, but the rate of decline has slowed down in recent years.

Emissions of nitrogen oxides (NO_x) have more than halved since 1990. Emissions were approximately 128,000 tonnes in 2019 and between 2018 and 2019, emissions decreased by 7 per cent. The largest sources of emissions of nitrogen oxides are domestic transport, industry and machinery. Sweden is also affected by emissions from international shipping, but it is not included in the statistics on national emissions.

Overall, total emissions have decreased in nearly all sectors. Mainly in the transport sector, despite the fact that emissions between 2011 and 2016 saw increased emissions of NO_x from passenger cars, but emissions have decreased since 2016. Between 2018 and 2019, emissions from passenger cars decreased by 8 per cent. The overall reduction in the transport sector is mainly due to catalytic exhaust purification in heavy trucks.

Emissions of non-methane volatile organic compounds (NMVOC), have more than halved since 1990 and are continuing to decrease. In 2019, emissions were approximately 134 thousand tonnes, which is a decrease of 2 per cent since 2018. The main sources of emissions of non-methane volatile organic compounds are products containing solvents, industry, in particular refineries, and agriculture.

Road traffic emissions of NMVOCs had previously been large but have decreased since 1990 and continue to decrease continuously due to stricter emission requirements. Carbon monoxide (CO) emissions have also decreased since the 1990s because of the mandatory fitting of catalytic converters to the exhaust system of vehicles.

What are the main causes of air pollution in Sweden?

Sulphur dioxide (SO₂) emissions are mainly produced by industry, which accounts for 77 per cent of the total national emissions. Emissions of sulphur dioxide come mainly from industrial processes. However, emissions from combustion are steadily declining, as fuels with a high sulphur content are being replaced by low-sulphur fuels and biofuels.

The main source of ammonia (NH₃) emissions comes from animal waste in the form of manure. In 2019, the total emissions of ammonia, (NH₃) were estimated to be approximately 53 thousand tonnes, which corresponds to a decrease of 11 per cent compared with 1990. Emissions between 2018 and 2019 have gone down by approximately 0.2 kilotons which correspond to a reduction of around 0.4 per cent. The agricultural sector, where storage and use of manure, in particular, is a major source of emissions, accounts for 88 per cent of total emissions in 2019. The reduction in emissions since 1990 is mainly due to the fact that the number of animals in agriculture has decreased and thus the emissions from manure management have also decreased. An increase in imports of dairy and meat products means that an increasing share of emissions instead takes place in other countries.

Another major source of pollution comes in the form of the microscopic particles of PM2.5 and the slightly larger ones, PM10. Emissions of small particles, PM2.5, were just over 18,000 tonnes in 2019, which is a decrease of 61 per cent since 1990. The biggest source of emissions of PM2.5 is from the heating of homes and premises through the burning of wood. Other major sources are domestic transport and industry. The largest source of road traffic's emissions of particles into the air comes from the wear and tear of roads, the abrasion of tyres and vehicle brakes. These emissions have marginally increased by just over 30 per cent since 1990 when the total volume of traffic increased. At the same time, emissions of particles from fuel use in road traffic decreased overall since 1990. This was due to higher quality fuel and stricter emission requirements.

What can be done to improve air quality in Sweden?

The tax on emissions of nitrogen oxides, the so-called nitrous oxide (NO_x) tax, has contributed to the reduction of emissions from electricity and heat production and industrial combustion.

The possible health effects of air pollution are monitored by the Swedish Environmental Protection Agency. They monitor, amongst other things, the number of people who are exposed to high levels of particles and nitrogen dioxide and for which levels they are exposed to carcinogens in urban air. Various studies are also conducted on the relationship between air pollution and various ailments and health effects.

Particulate emissions from road traffic, machinery and small-scale wood burning need to be reduced, as well as emissions of nitrogen oxides (NO_x) and volatile organic compounds (VOC) that contribute to the formation of ground-level ozone (O₃). The introduction of fuel and purification equipment requirements, as well as a further reduction in the use of studded tires, could contribute to a positive improvement of air quality in many urban areas.

Which city in Sweden had the highest levels of air pollution?

In certain areas of Sweden, the air quality for some polluting substances has improved, whilst others remain unchanged. But the levels are still high enough to be harmful to human health. The limit value for harmful particles in the air measuring 10 micrometres in diameter, PM10, was exceeded in the three municipalities of Sundsvall, Södertälje and Visby. This means that Sweden may have to pay a penalty fee to the EU.

When considering the concentrations of fine particulate matter, Visby exceeded the limit for 46 days in 2017. This is mainly due to the lime gravel that is spread over the roads in the winter months to provide traction over the icy surface. Sundsvall is another city where the limit value was exceeded for 40 days last year. This is due to the fact that it is located between two tall mountains and therefore the airflow does not carry away the polluted air. It also means that the problems with inversion are greater than in many other places. Södertälje municipality exceeded the limit value for 37 days in 2018. The reason for this is that a canal bisects the urban area and has limited ways of crossing it. This leads to a concentration of vehicle emitted particles close to the bridges. It is estimated that over 38,000 vehicles cross the canal on a daily basis. Because of the winter weather, many cars use studded tyres for extra traction but these studs considerably add to the large amount of road dust suspended in the air.

Stockholm exceeded the nitrogen dioxide (NO₂) limit value for 29 days, these high levels were due to road traffic, mainly emissions from diesel vehicles. The total traffic volume on the Essingeleden in 2018 increased by three per cent when compared to previous years. The proportion of heavy traffic and queuing are other factors that have a major impact on nitrogen dioxide emissions, something that has been attempted to address by the introduction of a congestion tax. Additionally, various environmental zones have already been introduced with the aim of reducing heavy traffic. In January, Hornsgatan in Södermalm will be designated as a class 2 environmental zone, which means that only light vehicles with emission class "Euro 5" or newer may enter. This approximately corresponds to vehicles manufactured from 2011 onwards.

Gothenburg’s problem with high levels of nitrogen dioxide (NO₂) is mainly due to the busy traffic routes that run through the central parts of the city. In addition, Gothenburg has the largest port in Scandinavia so vehicles travelling to and from the port go through the low-lying central areas of the city, which results in large emissions of nitrogen dioxide from their diesel engines. The city is also surrounded by hills and ridges, which creates conditions for stagnant air. When the air remains still, the air pollutants are not vented away but accumulate, which gives high levels. In Gothenburg, the limit value was exceeded for 21 days.

What does the future hold with regards to air quality in Sweden?

Sweden has on average lower amounts of small particles in the air than what the World Health Organisation (WHO) recommends, and internationally Swedes have a low risk of becoming ill from poor quality air, but even here at home thousands of people die every year as a result of pollution.

Stockholm residents, for example, live on average six months shorter due to air pollution. Negligible if you compare with heavy smoking which shortens life by several years, but comparable with passive smoking.

Each local authority is required to check that the environmental quality standards (EQS) for outdoor air are complied with within their locality. The control shall take place through measurement, model calculation or so-called objective estimation, and the authorities may carry out the control either on their own or in collaboration with other municipalities.

What are the effects on health by breathing Sweden’s poor quality air?

Air pollution affects both human health and the environment. It can make people sick and shorten life expectancy. It also contributes to plant damage, corrosion, eutrophication, acidification and climate change, especially when high levels occur near a source of pollution or in a densely populated area.

There are a variety of activities in society that contribute to air pollution. They are formed, amongst other things, during combustion, emissions in industries or from quarrying.

The most common air pollutants consist of nitrogen and sulphur oxides, ground-level ozone and suspended particles of various sizes and compositions. Other major air pollutants are hydrocarbons, such as benzene and polycyclic aromatic hydrocarbons (PAHs), as well as carbon monoxide and heavy metals.

Air pollution causes, among other things, cardiovascular disease and respiratory diseases. For small particles, no safe levels have been found and therefore one should strive for as low emissions as possible.

Children are particularly vulnerable to air pollution. Children are very active and are always moving. They have a faster rate of breathing yet their lungs are smaller. This means that relatively more air pollutants are absorbed in a child's airways and lungs when compared to adults. Children's lungs, brains and internal organs grow rapidly during the first few years of life, which makes them extra sensitive to health effects. Children's immune systems are also developing and therefore children often suffer from infections in the respiratory tract. In addition, children are often more sensitive to pollutants, than adults and react differently when they stay in polluted air environments.

Air pollution often aggravates respiratory diseases. For example, exposure to traffic pollutants can be linked to symptoms and hospitalisation in children with asthma. No lower limit for impact has been observed and therefore it is beneficial to have as little pollution as possible.

When children are exposed to air pollution for a long time, the development of the lungs can be affected in a way that the lungs grow worse and that their function is affected. The development of a baby's lungs is also important for health later in life. It is therefore important that the air environment as a whole is good where children are growing up. Very often schools are located in city centres near busy roads which is possibly the worst place to find pollution.

Air pollution can affect children even before birth by causing both low birth weight and premature births. Protecting the health of mothers is therefore protecting the health of their unborn children.