Significant improvements of the air quality in the cities and decreased emission of air pollutants from industry have occurred over the last decades. However, air pollution continues to be one of the most important environmental problems in Denmark and is linked to considerable impacts on human health and the environment.

Health problems caused by air pollution are particularly a problem in the larger cities. The main concerns are particulate matter (PM) and nitrogendioxide (NO₂). The yearly average 2010-EU limit value for air quality of NO₂ cannot be met. In 2009 all EU air quality limit values for PM₁₀,is being meet. For other air pollutants, including SO₂, CO, ozone, benzene, polycyclic aromatic hydrocarbons (PAHs) and heavy metals (Pb, As, CD and Ni) the EU air quality criteria are met. Estimations show that air pollution from particulate matter causes severe health problems estimated to cause 3 400 premature deaths each year.

Figure 1a + 1b (2.4.1/2.4.2). Yearly average concentration data of particulate matter (PM₁₀) in city air measured in the larger cities in Denmark, i.e. Copenhagen, Aarhus, Odense and Aalborg (Figure a) and the number of days with exceedance of the EU air quality limit 50mg /m³ (Figure b). The EU air quality limit of 50mg /m³ can only be exceeded 35 days a year. Source: National Environmental Research Institute. http://www2.dmu.dk/1_Viden/2_miljoe-tilstand/3_luft/4_maalinger/5_database/hentdata.asp

Figure 2 (2.4.1). Concentration of nitrogen oxide (NO₂) in city air measured in the larger cities in Denmark, i.e. Copenhagen, Aarhus, Odense and Aalborg. EUs air quality limit value is also shown.

Source: National Environmental Research Institute http://www2.dmu.dk/1_Viden/2_miljoe-tilstand/3_luft/4_maalinger/5_database/hentdata.asp

Emission of particulate matter causes severe health problems, resulting in an increased number of cases and worsening of asthma attacks, chronic and acute bronchitis and increased hospitalisation from cardiovascular diseases. An estimated 3 400 premature deaths each year, mainly among people already suffering from respiratory and cardiovascular diseases, has been calculated based on city air quality measurements.

Figure 3 (8.3.1). Incidence of respiratory diseases among adults and children in Denmark. In 2005 no complete data series is available.

Deposition of nitrogen compounds to the aquatic and terrestrial areas have been decreasing over the last decades and from 1989 to 2008 the decrease is estimated at 28% and 30%, respectively. Terrestrial deposition of sulphur has decreased by 66% from 1989 to 2008 while no significant change in deposition of phosphorus has been estimated. Deposition of nine heavy metals (Cr, Mn, Fe, Ni, Cu, Zn, As, Cd and Pb) has remained unchanged since 2005.

Figure 4 (6.7.3). Atmospheric deposition of nitrogen from air in kg N per ha in 2008. Source: National Environmental Research Institute (unpublished data)

Figure 5 (6.7.3). Atmospheric deposition of sulphur in kg per ha in 2008. Source: National Environmental Research Institute (unpublished data)

Although deposition of acidifying and eutrophying air pollutants is decreasing, the critical loads to sensitive habitats continue to be exceeded for sulphur and nitrogen. Also ground-level ozone frequently exceeds the critical level for toxicity effects on plants.

Figure 6 (6.7.1): The average atmospheric deposition of nitrogen (N) to Danish land-based areas. Critical loads for some of the most sensitive ecosystem areas and hardwood are included in the figure. For comparison a conventional corn field is fertilised with approximately 150 kg N per year. Source: National Environment Research Institute and Forest and Nature Agency

The National Danish emission inventory data of time series of air pollutants are publicly available at NERI’s website : http://www.dmu.dk/Luft/Emissioner/Air+pollutants/

The main sources of emissions of the acidifying gases sulphur dioxide (SO₂) and nitrogen oxides (NO_x) are the industrial, energy, and transport sectors, while emissions of ammonia (NH₃) are almost entirely from the agricultural sector. In 2008, emissions of SO₂ from the industry and energy sectors were 28 % and 34 % respectively. The transport sector accounts for 47 % of the total emissions of NO_x and the agricultural sector for almost 98 % of emission of NH₃. The reduction in emissions of acidifying gases, measured as acidifying potential, was 29 % from 2000 to 2008.

Figure 7 (2.1.2). Emission of acidifying gases expressed as acidifying equivalence for sulphur dioxide (SO₂), nitrogen oxides (NO_x), and ammonia (NH₃). Reference: National Environment Research Institute

The most important ozone-forming air pollutants include non-methane volatile organic compound (NMVOC), carbon monoxide (CO), methane (CH₄) and nitrogen oxides (NO_x). The main sources of NMVOC are incomplete combustion in the transport sector and evaporation from the use of solvents in production. The reduction in emissions of ozone forming air pollutants, measured as ozone forming potential, was 23% from 2000 to 2008.

Figure 8 (2.2.1). Ozone-forming potential (NMVOC-equivalence) from emission of the most important ozone-forming air pollutants including non-methane volatile organic compounds (NMVOC), nitrogen oxides (NO_x), carbon mono-oxide (CO) and methane (CH₄).

In general, the most important sources of heavy metal emissions are from energy production, i.e. combustion of fossil fuel and waste. Heavy metal emissions have decreased substantially over the last decades. From 1990 to 2008, the reduction of Hg, Cd and Pb amounted to 75%, 63% and 93%. Since 2000, the decrease has been much less, amounting to 20-25% for the three compounds.

Increased combustion of wood in the residential sector has caused emissions of PAHs and dioxin to increase. PAHs increased by 156% and dioxin by 53% from 1990 to 2008.

Figure 9 (2.3.2). Emission of heavy metals (mercury (Hg), cadmium (Cd) and lead (Pb) distributed on economic sectors in 2008. The waste sector contributes with the highest levels of emissions of heavy metals.

Figure 10 (2.3.1). Emissions of heavy metals, PAHs and dioxins. Emissions have been decreasing except for PAHs.

The main sources of emissions of the acidifying gases sulphur dioxide (SO₂) and nitrogen oxides (NO_x) are the industrial, energy, and transport sectors, while emissions of ammonia (NH₃) are almost entirely from the agricultural sector. In 2008, emissions of SO₂ from the industry and energy sectors were 28 % and 34 % respectively. The transport sector accounts for 47 % of the total emissions of NO_x and the agricultural sector for almost 98 % of emission of NH₃. The reduction in emissions of acidifying gases, measured as acidifying potential, was 29 % from 2000 to 2008.

Emissions of heavy metals and selected organic compounds are to be restricted to the 1990-emissions level according to the Danish obligations through international agreements (UNECE-LRTAP). Only emissions of PAHs do not meet the emissions reduction obligation.

Table 1. Overview of emissions of air pollutants in 2008, emissions ceilings and projections in 2010, 2015 and 2020. Projections of NO_x emissions are based on the use of ’old‘ emission factors for heavy road transport as used originally and an expected reduction of 5000 tons NO_x due to a newly introduced NO_x tax. Projections of emissions reduction of NMVOC are based on projections of fuel composition from 2008. Projections of ammonia are excluding emissions from crops. Source: National Environmental Research Institute. http://www.dmu.dk/Luft/Emissioner/Air+pollutants/

Table 2. Emissions of air pollutants of heavy metals, dioxin and PAHs. Source: National Environmental Research Institute. http://www.dmu.dk/Luft/Emissioner/Air+pollutants/

The large reduction in emissions of SO₂ is mainly due to the installation of desulphurisation plants, a tax on sulphur emissions, and the use of fuels with lower content of sulphur in public power and district heating plants.

The reduction in emissions of NO_x is due to an increased use of catalysts in cars and the installation of low-NO_x burners and de-nitrifying units in power and district heating plants.

The reduction in NH₃ is due to the adoption of a series of national action plans on the aquatic environment during the last twenty years, and the Ammonia Action Plan. These action plans set limits for the loss of nitrogen to the environment from the agricultural sector.

To meet reduction goals for NO_x, NMVOC, PAHs and air quality limit values for NO₂, further reduction measures will be initiated as described in the Danish Air Strategy from 2008. For particulate matter, a strengthening of existing environmental zones, filters in new taxis and a tax on cars without filters are measures which have been implemented. For PAHs, a legal notice that sets emission limits for wood‑burning stoves and boilers went into force in June 2008. An action plan for NO₂ is expected to emerge in 2010. Also the government plan for ‘Green Growth’ describes improvements for air quality.

The large reduction in Pb emissions is due to a gradual shift towards unleaded gasoline being essential for catalyst cars. Other reductions in emissions of heavy metals are mainly due to the increased use of gas‑cleaning devices at power and district heating plants (including waste incineration plants).

Reference

• Normander, B., Henriksen, C.I., Jensen, T.S., Sanderson, H., Henrichs, T., Larsen, L.E. & Pedersen, A.B. (red.) 2009: Nature and Environment 2009 – Part B: Factsheets. National Environmental Research Institute (NERI), Aarhus University, 170 p. – NERI scientific report series, no. 751. (In Danish) http://www.naturogmiljoe.dmu.dk/
• National Environmental Research Institute. Homepage for air quality data from the Danish monitoring program on air quality in Danish cities. Aarhus University http://www2.dmu.dk/1_Viden/2_miljoe-tilstand/3_luft/4_maalinger/5_database/hentdata.asp
• National Environmental Research Institute. Homepage for yearly monitoring reports of assessment of air quality data. http://www.dmu.dk/Luft/Maaling/Aarsrapporter/
• National Environmental Research Institute. Homepage for monitoring data for air quality in the country side and data on deposition of nitrogen, phosphorous and sulphur compounds as well as ozone, heavy metals and hazardous organic compounds. http://www.dmu.dk/Luft/Luftforurenings-modeller/Deposition/
• National Environmental Research Institute. Emission inventory - air pollutants in Denmark. Aarhus University http://www.dmu.dk/Luft/Emissioner/Air+pollutants/ (in English)
• Transport of Transport (previously Ministry of Traffic) 2003: Particle statement (Partikelredegørelse). http://www.trm.dk/sw1388.asp
• Government 2008: Clean air for everybody (Danish Air Strategy: Ren luft til alle). http://www.mim.dk/Nyheder/Pressemeddelelser/2008/20080616_luftstrategi.htm
• Government 2009: Action plan “Green Growth”. http://www.mim.dk/NR/rdonlyres/D5E4FC9A-B3AC-4C9A-B819-C42300F23CCA/0/GROENVAEKST_2904rapporten.pdf (in Danish)