Denmark is officially known as the Kingdom of Denmark is situated in northern Europe to the south of Norway and Sweden. It consists of a peninsula and 43 islands. In 2020 the population was estimated to be in the region of 5.8 million people.
In December 2020, Denmark’s air quality index showed the air quality to be “Good”, according to the suggested figures by the World Health Organisation (WHO). In the capital city of Copenhagen, the air quality was “Good” with a reading of 18 US AQI. The levels of the main pollutants were as follows: - PM2.5 - 4.4 µg/m³, PM10 - 8.9 µg/m³, sulphur dioxide (SO2) - 0.1 µg/m³ and carbon monoxide (CO) - 0.2 µg/m³.
In the world ranking of dirtiest cities in 2019, Denmark was ranked as 84 out of a total of 98 countries.
A new overview of air quality in Copenhagen shows many particles that are harmful to health on some roads and in the Inner City. It shows the results of a new collaboration between Google and the City of Copenhagen, which has had a car driving around the streets of Copenhagen to measure and map air pollution.
The results already show a pattern in Copenhagen. They show that there is a significantly higher level of ultrafine particles on the busiest roads and in the inner city. Ultrafine air particles are considered to be the most harmful particles to health and originate especially from the combustion and exhaust from diesel engines. The project provides for the first time the opportunity to measure this type of particles which have not been mapped before. The E20 motorway south of the city in particular and access roads such as Lyngbyvejen and Folehaven have a high level of ultrafine particles. In the central part of the city, HC Andersens Boulevard, Børsgade and Nørre Voldgade also stand out.
Aarhus University estimated in a statement last year that 3,200 Danes die a year due to poor air quality. In Copenhagen alone, about 550 people die prematurely every year due to air pollution.
From 1 January 2010, there was a supplement introduced to the weight and ownership tax of DKK 1,000 annually. To avoid the surcharge, a car must emit a maximum of 5 micrograms of particles per kilometer. It is thus a matter of having an efficient particulate filter fixed, or buying a newer car that stays below the limit.
At the street stations, the traffic immediately driving past the station is the main source of substances such as nitrogen oxides, carbon monoxide and to some extent PM10 (particles less than 10 microns). The street stations are in all cases located on the pavement immediately up to the carriageways on a busy street in the city centre. The results give an impression of the pollution you are exposed to in "street spaces", as - depending on the meteorological conditions - there can be large variations over smaller distances.
Because many people currently have to stay home and work or take time off altogether, cars are also increasingly allowed to stay in the garage. This can be clearly read on measurements of the air quality in Copenhagen. Here, measuring stations on, among other places, the busy HC Andersens Boulevard register a marked decrease in NOx, which is the harmful exhaust gas that cars emit. From a level of 273.12 µg/m³ on Thursday, 27th February at 7.30 am to this Wednesday morning to be all the way down to just 66 µg/m³. It should be noted that there may be fluctuations from day to day depending on how much it blows and the direction of the wind. But the trend is clear in recent weeks; the curve has been sharply downward. There is a measurable decline in air pollution. It is actually as expected when car traffic so much lower, which is one of the major local sources of air pollution. The interesting thing is that it can be seen here in black and white that it will make a huge difference if car traffic in Copenhagen is reduced.
But while the declining pollution may not be so surprising, the coming weeks with a Denmark on low gear during the corona crisis may, in turn, give researchers a unique opportunity to document the consequences of the normally dense car traffic in the city. There is now the opportunity to document the effect over a longer period of time under many different meteorological conditions.
Ironically, while NOx emissions from cars have fallen during the corona pandemic, the particulate pollution from, for example, wood-burning stoves can conversely increase because more people are at home during the day. How the two factors outweigh each other is still too early to say.
There are an estimated 7,000 kilometres of dedicated cycle tracks and lanes in Denmark. In Copenhagen a system of interconnected green cycle routes is currently under construction. The ultimate goal is to provide a safe and pleasant, yet fast network across the city. It is hoped to reach at least 100 kilometres on completion. One problem that this will bring will have to be solved. There is a general lack of dedicated spaces where bicycles can safely be left.
Air pollution with NOx gases comes primarily from local traffic and is especially a challenge in cities. NOx is a collective term for nitrogen oxide (NO) and nitrogen dioxide (NO2). Nitrogen dioxide is harmful to health in itself. In addition, NOx can react with ammonia in the air to form secondary particles that are harmful to health in line with directly emitted particles. Nitrogen from the air is deposited on surfaces where it has a fertilizing effect. Air pollution with nitrogen compounds can therefore contribute to over-fertilization (eutrophication), which can lead to algae blooms in water areas and loss of biodiversity in nutrient-poor habitats.
In order to reduce pollution by NOx from cars, trucks and other vehicles using internal combustion engines could be retrofitted with NOx cleaning systems. There are also requirements for NOx purification of new ship engines, work machines and power plants.
From 2008-2010, environmental zones were established in the five largest Danish cities (Copenhagen, Frederiksberg, Aalborg, Aarhus and Odense). In the environmental zones, requirements are set for emissions of NOx and other air pollutants from lorries. In May 2019, the Folketing adopted stricter environmental requirements for trucks, buses and vans. Today, there are strict environmental requirements from the EU for new vehicles. The EU has introduced new measurement methods where car emissions are measured under real driving conditions (RDE real driving emissions) to prevent tampering with car emissions.
In the EU, a limit value of 40 µg/m³ has been set for the annual average of the air content of NO2. The limit value is set to protect human health. HC Andersens Boulevard in Copenhagen is considered to be one of the most polluted places in Denmark and is therefore used as a reference for compliance with the EU limit value.
All Danish cities comply with the NO2 limit value. The highest concentrations are measured on the busiest roads; the annual average at HC Andersens Boulevard in 2017 was 38.4 µg/m³ and in Banegårdsgade in Aarhus 28 µg/m³. The concentrations of NO2 measured at the street stations in 2017 have decreased compared to the concentrations measured in 2016.
Particle pollution is the biggest problem for health, and those particles come, among other things, from the exhaust emissions from cars, trucks and ships, coal-fired power plants and from wood smoke. In addition, there are also particles that come from tyres and brakes, wear of roads, salt water spray and dust from rooftops.
There are approximately 750,000 wood-burning stoves in Denmark, making them the largest source of air pollution. In Denmark, the particles from these stoves, according to DCE, are responsible for approximately 550 annual deaths. Especially the old wood-burning stove from before 2005 which emit far more harmful particles than others.
In 2005, the total particle emission was about 27,787 tonnes of PM2.5 in Denmark of which about 17,665 tonnes were from residential wood combustion. Another major source is road traffic, which contributes with about 20 per cent of the total emission of PM2.5.
According to figures released by the reputable air monitoring company IQAir.com the cleanest city in Denmark is the capital, Copenhagen. Only during the month of April did figures show a “Moderate” reading for PM2.5 (between 12.1 and 35.4 µg/m³). June, July, August and November returned a “Good” reading between 10 and 12 µg/m³. For the remaining seven months, Copenhagen achieved the target figure as suggested by the WHO (0 – 10 µg/m³).
It has been proposed that car-free districts and car-free streets should be created, that the environmental zones must be expanded and tightened considerably, and that the number of parking spaces must be reduced. Also suggested was the creation of shortcuts for electric cars, buses and bicycles by closing roads for transit with petrol and diesel cars.
The World Health Organisation (WHO) study also shows that 90 per cent of the world's population breathes polluted air. And while it is often a major threat to the poorest countries of the world, there are actually 400,000 deaths within the EU's borders each year.
A report from the University of Copenhagen and the Danish Heart Association from January 2018 shows a rather disappointing result. 2140 Danes die every year from heart disease caused by air pollution.
The concentration often rises across large cities, and is known as smog. However, the problem is already alarming before it becomes the visible smog. Therefore, since 2007, “The World Air Quality Index” has collected data from measuring stations around the world, located in cities around the world.
Firewood smoke contains a complex mixture of pollutants such as particulate matter, inorganic gases (e.g. carbon monoxide, nitrogen oxides, and sulphur dioxides), polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOCs), which have the potential to harm the environment and human health. Many studies have been conducted on the monitoring of both individual gaseous pollutant and a combination of mixes.
Volatile organic compounds are chemicals that contain carbon, hydrogen and oxygen and are gases at room temperature. VOCs are organic chemical compounds whose composition makes it possible for them to evaporate under normal indoor atmospheric conditions and pressure, this excludes carbon monoxide, carbon dioxide, carbonic acid, metallic carbides and ammonium carbonate.
Many diseases can be related to air pollution. This applies to both cardiovascular diseases such as heart attacks and blood clots, and lung diseases such as bronchitis, asthma and coughs as well as lung cancer. It is estimated that approximately 6,000 Danes die from air pollution every year and in Europe there are hundreds of thousands who die prematurely because they inhale polluted air. An analysis shows that Danes live on average one year and three months shorter due to air pollution and noise, but with large geographical differences.
The dirty air is also expensive for society's common fund. Every year, more than 10,000 Danes become seriously ill, and have millions of sick days, which are as a direct result of the pollution. According to the Ecological Council, air pollution costs the Danish economy NOK 30-40 billion every year.
Particles with a diameter of up to 2.5 microns are called fine particles and are known as PM2.5. The largest source of fine particles are emissions from traffic and smoke from wood-burning stoves, as well as so-called secondary particles, which are formed from sulphur oxides and nitrogen filters from combustion plants and traffic. The fine particles are characterized by the fact that they can be transported over long distances. The pollution of the air with fine particles is dominated by foreign sources that contribute 75 per cent. The contribution from wood-fired plants to the discharge of PM2.5 from Danish sources amounts to up to 2/3 of Danish sources.
Particles with a diameter of up to 10 microns are referred to as PM 10. Particles between PM2.5 and PM 10 are deposited relatively quickly to surfaces due to gravity and originate to a large extent from local sources such as the vortex of dust from soil, brakes, asphalt and tyres as well as sea salt.