Aarhus Universitets segl

No. 18: Annual Danish Informative Inventory Report to UNECE

Nielsen, O.-K., Winther, M., Mikkelsen, M.H., Hoffmann, L., Nielsen, M., Gyldenkærne, S., Fauser, P., Plejdrup, M.S., Albrektsen, R., Hjelgaard, K. & Bruun, H.G. 2012. Annual Danish Informative Inventory Report to UNECE. Emission inventories from the base year of the protocols to year 2010. Aarhus University, DCE – Danish Centre for Environment and Energy, 669 pp. Scientific Report from DCE – Danish Centre for Environment and Energy No. 18. http://www2.dmu.dk/Pub/SR18.pdf


I Background information on emission inventories

Annual report

This report is Denmark’s Annual Informative Inventory Report (IIR) due March 15, 2012 to the UNECE-Convention on Long-Range Transboundary Air Pollution (LRTAP). The report contains information on Denmark’s inventories for all years from the base years of the protocols to 2010.

The air pollutants reported under the LRTAP Convention are SO2, NOX, NMVOC, CO, NH3, As, Cd, Cr, Cu, Hg, Ni, Pb, Se, Zn, dioxins/furans, HCB, PAHs, TSP, PM10 and PM2.5.

The annual emission inventory for Denmark is reported in the Nomenclature for Reporting (NFR 2009) format. In December 2008 new reporting guidelines were decided by the EMEP Executive Body. Many of the new elements and demands in the reporting guidelines have not been implemented yet. The reason for this is that they require significantly more resources, which are not currently available.

The issues addressed in this report are: trends in emissions, description of each NFR category, uncertainty estimates, recalculations, planned improvements and procedures for quality assurance and control. The structure of the report follows to the extent possible the proposed outline.

Information contained in this report is available to the public on the Danish Centre for Environment and Energy (DCE), Aarhus University’s homepage:


and this report and the NFR tables are available on the Eionet central data repository:


Responsible institute

The DCE-Danish Centre for Environment and Energy, Aarhus University, is on behalf of the Danish Ministry of the Environment responsible for the annual preparation and submission to the UNECE-LRTAP Convention of the Annual Danish Emissions Report and the inventories in the NFR format. DCE participates in meetings under the UNECE Task Force on Emission Inventories and Projections and the related expert panels, where parties to the convention prepare the guidelines and methodologies on inventories.

II Trends in emissions

Acidifying gases

In 1990, the relative contribution in acid equivalents was almost equal for the three gases SO2, NOx and NH3. In 2010, the most important acidification factor in Denmark is ammonia nitrogen and the relative contributions for SO2, NOX and NH3 were 6 %, 36 % and 58 %, respectively. However, with regard to long-range transport of air pollution, SO2 and NOX are still the most important pollutants.

Sulphur dioxide (SO2)

The main part of the SO2 emission originates from combustion of fossil fuels, i.e. mainly coal and oil, in public power and district heating plants. From 1980 to 2010, the total emission decreased by 97 %. The large reduction is mainly due to installation of desulphurisation plants and use of fuels with lower content of sulphur in public power and district heating plants. Despite the large reduction of the SO2 emissions, these plants make up 28 % of the total emission. Also emissions from industrial combustion plants, non-industrial combustion plants and other mobile sources are important. National sea traffic (navigation and fishing) contributes with about 13 % of the total SO2 emission in 2010. This is due to the use of residual oil with high sulphur content.

Nitrogen oxide (NOx)

The largest sources of emissions of NOX are road transport followed by other mobile sources and combustion in energy industries (mainly public power and district heating plants). The transport sector is the sector contributing the most to the emission of NOX and, in 2010, 45 % of the Danish emissions of NOX stems from road transport, national navigation, railways and civil aviation. Also emissions from national fishing and off-road vehicles contribute significantly to the NOX emission. For non-industrial combustion plants, the main sources are combustion of gas oil, natural gas and wood in residential plants. The emissions from energy industries have decreased by 72 % from 1985 to 2010. In the same period, the total emission decreased by 53 %. The reduction is due to the increasing use of catalyst cars and installation of low-NOX burners and denitrifying units in power plants and district heating plants.

Ammonia (NH3)

Almost all atmospheric emissions of NH3 result from agricultural activities. Only a minor fraction originates from road transport (1.9 %) and stationary combustion (0.3 %). This share for road transport increased during the 1990’ties and early 2000’s due to growing use of catalyst cars. In more recent years the share is again decreasing due to more advanced catalysts being implemented. The major part of the emission from agriculture stems from livestock manure (85 %) and the largest losses of ammonia occur during the handling of the manure in stables and in field application. Other contributions come from use of mineral fertilisers (5 %), N-excretion on pasture range and paddock (3 %), sewage sludge used as fertiliser, crops and ammonia used for straw treatment (8 %) and field burning (less than 1 %). The total ammonia emission decreased by 36 % from 1985 to 2010. This is due to the active national environmental policy efforts over the past twenty years.

Other air pollutants

Non-methane volatile organic compounds (NMVOC)

The emissions of NMVOC originate from many different sources and can be divided into two main groups: incomplete combustion and evaporation. Road vehicles and other mobile sources such as national navigation vessels and off-road machinery are the main sources of NMVOC emissions from incomplete combustion processes. Road transportation vehicles are still the main contributors, even though the emissions have declined since the introduction of catalyst cars in 1990. The evaporative emissions mainly originate from the use of solvents and the extraction, handling and storage of oil and natural gas. The emissions from the energy industries have increased during the nineties due to the increasing use of stationary gas engines, which have much higher emissions of NMVOC than conventional boilers. The total anthropogenic emissions have decreased by 55 % from 1985 to 2010, largely due to the increased use of catalyst cars and reduced emissions from use of solvents.

Carbon monoxide (CO)

Mobile sources and non-industrial combustion plants contribute significantly to the total emission of this pollutant. Transport is the second largest contributor to the total CO emission. In 1990 a law forbidding the burning of agricultural crop residues in the fields was implemented, which caused a significant reduction in CO emission. The emission decreased further by 45 % from 1990 to 2010, largely because of decreasing emissions from road transportation.

Particulate Matter (PM)

The particulate matter (PM) emission inventory has been reported for the years 2000-2010. The inventory includes the total emission of particles Total Suspended Particles (TSP), emission of particles smaller than 10 µm (PM10) and emission of particles smaller than 2.5 µm (PM2.5).

The largest PM2.5 emission sources are residential plants (71 %), road traffic (9 %) and other mobile sources (8 %). For the latter, the most important sources are off-road vehicles and machinery in the industrial sector and in the agricultural/forestry sector (32 % and 37 %, respectively). For the road transport sector, exhaust emissions account for the major part (64 %) of the emissions. The PM2.5 emission increased by 30 % from 2000 to 2010, due to an increasing wood consumption in the residential sector.

The largest TSP emission sources are the residential sector and the agricultural sector. The TSP emissions from transport are also important and include both exhaust emissions and the non-exhaust emissions from brake and tyre wear and road abrasion. The non-exhaust emissions account for 62 % of the TSP emission from road transport.

Heavy metals

In general, the most important sources of heavy metal emissions are combustion of fossil fuels and waste. The heavy metal emissions have decreased substantially in recent years, except for Cu. The reductions span from 29 % to 91 % for Zn and Pb, respectively. The reason for the reduced emissions is mainly increased use of gas cleaning devices at power and district heating plants (including waste incineration plants). The large reduction in the Pb emission is due to a gradual shift towards unleaded gasoline, the latter being essential for catalyst cars. The major source of Cu is automobile tyre and break wear (93 % in 2010) and the increase from 1990 to 2010 is caused by increasing mileage.

Cadmium (Cd)

The main sources of emissions of Cd to air are combustion in energy industries (mainly combustion of wood, wood waste and municipal waste) and manufacturing industries (mainly combustion of residual oil). In the transport sector emissions from passenger cars is the main source contributing with 53 % of the sectoral emission in 2010. The emission from non-industrial combustion is dominated by wood combustion in residential plants which accounts for 78 % of the sectoral emission in 2010. Emissions from combustion in residential plants have increased by 119 % since 1990. The decreasing emission from energy industries are related to the decreasing combustion of coal.

Mercury (Hg)

The largest sources of Hg emissions to air are waste incineration and coal combustion in energy industries. Due to improved flue gas cleaning and decreasing coal combustion the emissions from Energy industries decreased by 76 % from 1990-2000. Non-industrial combustion is dominated by wood combustion in residential plants while emissions from the waste sector mainly stems from cremation. The variations in emissions from industrial processes are caused by a shut down in 2002 followed by re-opening and a second shut in 2005 down of the only Danish electro-steelwork.

Lead (Pb)

The main Pb emission sources are combustion in residential plants and energy industries and transport. In earlier years combustion of leaded gasoline was the major contributor to Pb emissions to air but the shift toward use of unleaded gasoline for transport has decreased the Pb emission from transport by 93 %. In the non-industrial combustion sector the dominant source is wood combustion in residential plants. The trend in the Pb emission from non-industrial combustion from 1990 to 2010 is almost constant. This is due to the shift towards unleaded gasoline, as this sector includes other mobile sources in household, gardening, agriculture, forestry, fishing and military, However this is counteracted by an increase in emission from residential plants. The decreasing emission from Energy industries (97 % from 1990 to 2010) is caused by the deceasing coal combustion.

Polycyclic aromatic hydrocarbons (PAHs)

The emission inventory for Polycyclic aromatic hydrocarbons (PAHs) includes four PAHs: benzo(a)-pyrene, benzo(b)-fluoranthene, benzo(k)-fluoranthene and indeno-(1,2,3-cd)pyrene. Benzo(b)fluoranthene and Benzo(a)pyrene contribute the major PAH emission by 31 % and 30 %, respectively. The most important source of PAH emissions is combustion of wood in the residential sector making up 88 % of the total emission in 2010. The increasing emission trend is due to increasing combustion of wood in the residential sector. The PAH emission from combustion in residential plants has increased by 17 % from 1990 to 2010.

Dioxins and furans

The major part of the dioxin emission owes to wood combustion in the residential sector, mainly in wood stoves and ovens without flue gas cleaning. Wood combustion in residential plants accounts for 64 % of the national dioxin emission in 2010. The contribution to the total dioxin emission from the waste sector (24 % in 2010) stems from accidental fires, especially building fires. The emission of dioxins from energy industries owes mainly to the combustion of biomass such as wood, wood waste and to a less extend agricultural waste.

Hexachlorobenzene (HCB)

Stationary combustion accounts for 98 % of the estimated national Hexachlorobenzene (HCB) emission in 2010. This is mainly due to combustion of municipal solid waste in heating and power plants. The HCB emission from stationary plants has decreased 81 % since 1990 mainly due to improved flue gas cleaning in MSW incineration plants. Wood combustion in households is an important source, too, and has increased by 302 % since 1990 due to increasing wood consumption.

III Recalculations and Improvements

Investigations and research carried out in Denmark and abroad produce new results and findings, which are given consideration and, to the extent possible, included as the basis for emission estimates and as data in the inventory databases. Furthermore, the updates of the EMEP/CORINAIR guidebook (Now the EMEP/EEA Guidebook), and the work of the Task Force on Emission Inventories and its expert panels are followed closely in order to be able to incorporate the best scientific information as the basis for the inventories.

The implementation of new results in inventories is made in a way so that improvements, as far as possible, better reflect Danish conditions and circumstances. This is in accordance with good practice. Furthermore, efforts are made to involve as many experts as possible in the reasoning, justification and feasibility of implementation of improvements.

In improving the inventories, care is taken to consider implementation of improvements for the whole time series of inventories to make it consistent. Such efforts lead to recalculation of previously submitted inventories. This submission includes recalculated inventories for the whole time series. The reasoning for the recalculations performed is to be found in the sectoral chapters of this report. The text below focuses on recalculations, in general, and further serves as an overview and summary of the relevant text in the sectoral chapters. For sector specific planned improvements please also refer to the relevant sectoral chapters.


Improvements and updates of the Danish energy statistics are made regularly by the producer of the statistics, the Danish Energy Agency (DEA). In close cooperation with the DEA, these improvements and updates are reflected in the emission inventory for the energy sector. The Danish energy statistics have, for the most part, been aggregated to the SNAP categorisation. This, however, does not include energy statistics for fuel consumption data for specific industries.

The inventories are still being improved through work to increase the number of large point sources, e.g. power plants, included in the databases as individual point sources. Such an inclusion makes it possible to use plant-specific data for emissions, etc, available e.g. in annual environmental reports from the plants in question.

Stationary Combustion

For stationary combustion plants, the emission estimates for the years 1990-2009 have been updated according to the latest energy statistics published by the Danish Energy Agency. The update included both end use and transformation sectors as well as a source category update.

The disaggregation of emissions in 1A2 Manufacturing industries and construction has been recalculated based on a new improved methodology. Thus, the estimated emissions in the subsectors are considerable, but the total emissions in sector 1A2 are relatively low.

The emissions from residential wood combustion have been recalculated based on improved technology disaggregation data. In addition the NMVOC emission factor has been improved for new stoves resulting in a decreased emission from this sector.

The NOx emission factor for natural gas consumption in large power plants has been updated according to Danish legislation[1].

The NMVOC emission factor for refineries has been included or revised for several years. This results in improved time series but also in large relative changes for some years.

The PM10 and PM2.5 emission factors for wood and straw have been recalculated to improve consistency with the TSP emission factor.

Mobile sources

The following recalculations and improvements of the emission inventories have been made since the emission reporting in 2011.

Road transport

The total mileage per vehicle category from 1985-2009 has been updated based on new data prepared by DTU Transport. Important changes are a different split of total mileage between gasoline and diesel passenger cars based on data for the year 2008 from the Danish vehicle inspection and maintenance programme. Also updated mileage for foreign vehicles driven on Danish roads has been included.


The sales distribution into engine sizes for harvesters has been updated for the years 2002, 2003 and 2009.


Emission factors derived from the new road transport simulations have caused some emission changes from 1985-2009.


Emission changes occur for the years 2007-2009, due to a correction in the representative aircraft type for new aircraft used for flying in Denmark. Due to an error F28 was previously used as a representative aircraft type for the new aircraft types CRJ9, E70, E170 and E175. However, F28 is a very old aircraft which cannot represent these new aircraft types. Instead new fuel consumption and emission factors have been calculated for the CRJ9, E70, E170 and E175 jets.

Fugitive emissions

Refineries: Emissions of NMVOC have been changed for the years 1994-2000 and 2002-2009 according to VOC measurements carried out in 2001, as no further information on fugitive emissions from the refineries are or will become available for other historical years. This is the result of an extended communication with one refinery leading to a recommendation to use measured emissions, and not an estimated emission calculated by weighting the measured emissions by the annual processed crude oil amount as done in previous inventories. The fugitive emissions are more related to other conditions than the processed amounts. The split of VOC emissions provided by the refineries have been revised in order to apply a more similar approach for the two refineries. For both refineries annual emissions of NMVOC are not available, and emissions are based on the provided VOC emissions and assumptions for the part of VOC being NMVOC and CH4, respectively. Assumptions are based on information from the refineries and on literature study of international proportions/conditions. In the previous inventory CH4 was estimated as 10 % of VOC based on information from one refinery.

Updated SO2 emissions for the years 2005-2009 provided by a refinery are included in the inventory.

Gas distribution: Emission factors for NMVOC for town gas distribution have been corrected for an error. Distribution of town gas is a minor source and the recalculation is insignificant for all years (< 0.001 % of the total fugitive NMVOC emission in 2009).

Offshore flaring: Activity data has been corrected for 2008 for two offshore installations. The calorific value has been corrected for the whole time series according to the average calorific value in the EU ETS reports for 2008-2010 which affects the emission factor for NOx, NMVOC, CO, particulate matter, heavy metals, dioxin and PAHs. Further, the emission factors for CO and NMVOC have been corrected by including a conversion from ms3 (standard m3) to mn3 (normal m3). The activity data has been updated according to the latest figures from the Danish Energy Agency (DEA).

Industrial processes

Production of chemical ingredients and treatment of slaughterhouse waste are transferred from Mineral products to Other production, consumption, storage, transportation or handling of bulk products (NFR 2G).

The emission factors applied for NMVOC from refining of sugar within the sector Other production have been revised.

Solvent and other product use

Improvements and additions are continuously being implemented due to the comprehensiveness and complexity of the use and application of solvents in industries and households. The main improvements in the 2011 reporting include the following:

  • Inclusion of NMVOC use and calculations of NMVOC emissions for the time period 1990 to 1994
  • Inclusion of Tobacco smoking and Combustion of Charcoal for Barbeques in Other Product Use


Compared with the previous NH3 and PM emissions inventory (submission 2011), some changes and updates have been made. These changes cause a decrease in the NH3 emission (1985 – 2009) and a decrease in the PM emission (2000 – 2009).

Emission of NH3 has decreased 1-3% in the period 1985-2009 compared to the submission 2011. The main reason for the decrease is an adjustment of emission factors for synthetic fertilisers. The emission factors have been updated in cooperation with the Danish Plant Directorate.

The PM emission decreases because a technical error in the calculation of PM from animal husbandry has been corrected.

The calculation of number of produced bulls has been changed to being based on slaughtering data from Statistics Denmark instead of annual census. An error in the calculation of number of weaners and fattening pigs has been corrected. Furthermore, the time series of the distribution of animals on deferent housings types have been reviewed by experts. These changes in activity data have influence on both NH3 and PM emissions.

The emission of NMVOC from crops has been recalculated for 2009 because of new data for agricultural land from Statistics Denmark.


Changes have been made to the methodology of accidental building and vehicle fires. For accidental building fires, the different building categories now also include additional buildings (sheds, greenhouses etc.) and container fires. Also there are now four damage categories; full, large, medium and small scale fires, corresponding to 100, 75, 30 and 5 % damage rate, respectively. The effect of these changes is a decrease in emissions between 4-9 % for particles and 44-47 % for NMVOC. Even though the number of included building fires is higher in this year’s inventory, the total emissions are lowered. In earlier years buildings like carports, sheds and greenhouses were categorised as detached houses and emissions from these fires were calculated based on average floor space and content masses that were much too high. The addition of the category additional buildings is the main reason for the lowered total emissions from accidental building fires.

For accidental vehicle fires, similar changes were made. Last year the damage rate was set to 70 % for all fires, but this year the damage rate was divided in four damage categories according to the measure of fire extinguishing; full, large, medium and small scale fires, corresponding to 100, 75, 30 and 5 % damage rate, respectively. These new damage categories give an average burnout for all vehicle categories in 2007-2010 of 34 % and thereby a reduction in emission of about 50 % compared with the 70 % burnout used in last year’s inventory.


[1] However, in general plant specific emission data are available.