3. atmospheric supply of nitrogen to the baltic sea in 2014 · in this chapter we also show and...

3. Atmospheric Supply of Nitrogen to the Baltic Sea in 2014

The EMEP/MSC-W model version rv4.9 has been used for the 2014 model runs, as well as for the estimation of historical nitrogen depositions in the period 1995-2014. The model was run in 50 km×50 km, in the EMEP domain. Meteorology, emissions, boundary conditions and forest fires for 2014 have been used as input. In addition, the SO2 emissions from the Holuhraun eruption in 2014 were included in the emission inventories. For the first time, DMS emissions are created ’on-the-fly’, e.g. they are meteorology dependent. Several modifications that affect aerosol production/modelling have been implemented in the EMEP/MSC-W model in 2016 (EMEP Status Report 1/2016). The main are: modification of the sea salt parameterisation, changes in the standard aerosol surface area and uptake rates, dust boundary conditions and an update of the split of particulate matter into elemental carbon, organic matter and the remainder. In addition, biogenic emissions of dimethyl sulphide (DMS) have been updated. DMS emissions are now calculated dynamically during the model calculation and vary with meteorological conditions, rather than being prescribed. The results of this latest version (rv4.9) of the EMEP/MSC-W model are presented in the present report. In this chapter we also show and discuss nitrogen emission data as used in the EMEP MSC-W model calculations performed in 2016 and presented to Second Joint Session of the Steering Body to the EMEP and the Working Group on Effects, which took place 13-16 September 2016 in Geneva. The emissions for 2014 have been derived from the 2016 official data submissions to UNECE CLRTAP as of May 2016. The gridded distributions of the 2014 emissions have been provided by the EMEP Centre on Emission Inventories and Projections (CEIP). The emissions for the period of 2000–2013 have been derived from the data submissions to UNECE CLRTAP as of May 2015. Re-submissions of emission data in 2016 are not included since the gridded data set for 2000–2013 has not been updated by CEIP this year. For international shipping emissions, EMEP/MSC-W has been using the TNO-MACC data set for 2011, i.e. no trends have been taken into account for the period since 2011. In the meantime, new emissions data have been generated using the Ship Traffic Emission Assessment Model (STEAM) developed at the Finnish Meteorological Institute (FMI). The STEAM model (Jalkanen et al., 2009; Jalkanen et al., 2012; Johansson et al., 2013) can provide fully dynamic ship emission inventories based on the AIS data (real ship movements tracked by the Automatic Identification System). The use of AIS data for air quality research is certainly welcome, but until now it is restricted by commercial data providers and maritime authorities, and it is not available for years before 2006. In addition, uncertainties remain on emission factors for different ship types, and on the practice of slow steaming in different European seas. Thus, also for this year’s status and trend modelling EMEP/MSC-W has used TNO-MACC data for international shipping, but the question about which emission data to use will be further investigated during the

EMEP Centres Joint Report for HELCOM

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future. The TNO-MACC data for Baltic ship emissions is identical with the official EMEP-CEIP data available on the Internet. The NOx emissions in the entire EMEP domain were reduced by 2% from 2013 to 2014, whereas NOx emissions from all HELCOM Contracting Parties were 3% lower in 2014. Ammonia emissions from the entire EMEP domain, as used for the EMEP/MSC-W model, increased 1.3%, and ammonia emissions from HELCOM countries increased by 4%, between 2013 and 2014. Compared to 2013 nitrogen oxides emissions in 2014 are lower (2-9%) in five out of nine HELCOM Contracting Parties (PL-9%, DK-8%, FI-5%, DE-4% and RUE-2%). Ship emissions of nitrogen oxides from the Baltic Sea were on the same level in 2013 and 2014 according to CEIP inventory. According to FMI inventory, ship emissions from the Baltic Sea were 1% lower in 2014 than in 2013. The increase of nitrogen oxides emissions between 2013 and 2014 can be noticed for Estonia (12%), Lithuania (11%), Sweden (7%) and Latvia (3%). In general, annual 2014 ammonia emissions in most of the HELCOM CPs remain on the similar level, within 1% range. Only in two countries, ammonia emissions in 2014 are significantly higher than in 2013. These are Latvia (19%) and Estonia (15%). In case of Germany, ammonia emissions, as used for modelling are 10% higher in 2014 than in 2013, but official ammonia emission from Germany re-submitted to CEIP in 2016 are only 1% higher in 2014. Calculated annual deposition of total nitrogen to the Baltic Sea basin in 2014 was 240 kt, approximately 9% higher than in 2013. Deposition of oxidised nitrogen was 6% higher and deposition of reduced nitrogen was 12% higher in 2014 compared to 2013. Since nitrogen emissions were on the same level in 2013 and 2014, the increase of deposition is mainly caused by meteorological conditions. Deposition of oxidised nitrogen accounted for 55% of total nitrogen deposition in 2014. The contributions from the main nitrogen emissions sources to nitrogen deposition into the Baltic Sea basin have been calculated for the year 2014. Germany and Poland are the main contributors to all kinds of nitrogen deposition. Ship traffic on the Baltic Sea is the contributor number three to oxidised nitrogen deposition when the official CEIP emissions are used. For comparison we have calculated contribution to oxidised nitrogen deposition in 2014 using the FMI emission from the ship traffic on the Baltic Sea. Then ship traffic on the Baltic Sea becomes the second most important contributor after Germany. The EMEP reports for HELCOM have been focused on the latest year with available deposition which in case of 2016 is 2014. However, time series of annual nitrogen depositions have been also calculated starting from 1995 until the latest available year. To be consistent with official EMEP data included in the status reports, historical period

Atmospheric Supply of Nitrogen to the Baltic Sea in 2014

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(from 1995) was not recalculated in the past with the latest model version each year, but only results from the last year were added to the time serious of the depositions. Another reason for not recalculating historical depositions was the luck of all necessary meteorological data for the past. 3.1 New historical depositions In 2016 consistent meteorological input data for the EMEP/MSC-W model were available for each year of the period 1995-2014. Therefore, for the first time in 2016, the same latest and the best version of the EMEP/MSC-W model has been used for calculating historical nitrogen depositions in the period 1995-2014. These historical depositions calculated in 2016 differ, sometimes significantly, from the time series of the depositions calculated in the past. Comparison of the old and new time series for annual deposition of nitrogen in the period 1995-2013 is shown in Fig. 3.1.

Figure 3.1. Comparison of old (calculated in 2015) and new (calculated in 2016) time series of nitrogen depositions (oxidised, reduced, dry and wet) to the Baltic Sea basin in the period 1995-2013.

The main differences between old and new time series can be noticed in depositions of oxidised nitrogen (dry + wet) and in depositions of wet (oxidised + reduced) nitrogen. Time series of dry depositions and depositions of reduced nitrogen are very similar. Comparison of the old and new time series for annual deposition of total nitrogen in the period 1995-2013 is shown in Fig. 3.2.


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Figure 3.2. Comparison of old (calculated in 2015) and new (calculated in 2016) time series of annual total nitrogen depositions to the Baltic Sea basin in the period 1995-2014. Historical depositions calculated with the latest EMEP/MSC-W model from 2016 are higher than the old depositions calculated with different model versions. Since the changes in the EMEP/MSC-W have been introduced gradually each year each next version was closer to the version from 2016. Therefore the old and new results are converging towards 2014. New historical depositions calculated with the latest EMEP/MSC-W model from 2016 are also available for nine sub-basins of the Baltic Sea and presented in BSEFS for nitrogen deposition on the HELCOM web pages. Compared to the old time series new nitrogen depositions are mostly higher, but there are differences, sometimes large, between individual sub-basins. There are three main reasons for the differences between old and new series:

1. Different model versions used for old calculations. In calculating old time series of nitrogen depositions a new model version was used practically every year and different versions were used for calculating old depositions. The same and the best, up to now, model version was used for calculating new time series of the deposition.


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2. Different emissions. Historical nitrogen and other emissions used as input to the model were updated several times in the past, so, old time series were based on inconsistent emission inventories. New time series are based on the latest, available from CEIP, emissions for the period 1995-2014.

3. Different meteorological input data. Two different sources of meteorological data were used in the past. Until 2009 meteorological input data were calculated using the PARLAM Numerical Weather Prediction (NWP). From 2010 until present meteorological data are calculated with the ECMWF NWP model with better resolution and better quality in general. A consistent meteorological input from the ECMWF NWP model is used for recalculating nitrogen depositions in the new time series.

It should be stressed that for calculating new time series of nitrogen depositions in the period 1995-2016, the best consistent version of the EMEP/MSC-W model was used, the latest and updated emissions served as input to the model and finally the most reliable and consistent meteorological data was used in the calculations. The comparison of model results with measurements in 2014 showed an improvement compared to 2013 and previous years. This improvement can be seen for all pollutants included in the EMEP/MSC-W model, also for nitrogen components. Here we present the comparison results for oxidised and reduced nitrogen for the years 2013 (Supplementary material to the EMEP Status Report 1/2015) and 2014 (Supplementary material to the EMEP Status Report 1/2016) in Table 3.1. In Table 3.1 we show for each component the number of stations where measurements were available and data coverage criteria were satisfied (N stat ), measured yearly average over all stations (Obs), modelled yearly average over all stations (Mod), bias

( %100

Obs

ObsMod) and correlation between observation and model for station yearly

averages (Corr). For three out of five components (including precipitation) which are presented in Table 3.1, bias in 2014 is lower than in 2013, for two is the same and only for one is higher. A significant improvement can be noticed in correlations between modelled and observed nitrogen depositions between 2013 and 2014. This improvement is visible for all five considered components. Concerning future, we plan to recalculate the historical nitrogen depositions each year with the latest version of the EMEP/MSC-W model and with the latest updated historical emissions. It means that historical depositions calculated next year can be slightly different. The main advantage of the method for calculating old time series was the stability of the historical results, which did not change from one year to another. However, when recalculating historical nitrogen depositions in the future we expect only minor changes in the results, because the changes in the model will be relatively small from one year to another and changes in historical emissions will not be dramatic either.


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Table 3.1. Comparison of model results and observations for 2014. Annual averages over all EMEP sites with measurements. Nstat = number of stations, wd=wet deposition, cp= concentration in precipitation, Corr. = spatial correlation coefficient.

Component Nstat Obs. Mod. Bias (%) Corr.

2013

4NH wd (µg N m-2) 47 12185 13641 12 0.82

4NH cp (mg N l-1) 47 0.35 0.37 5 0.58

3NO wd (µg N m-2) 47 10549 10390 -2 0.69

3NO cp (µg N l-1) 47 0.29 0.28 -6 0.59

Precipitation 47 39526 40471 2 0.81

2014

4NH wd (µg N m-2) 47 12554 14080 12 0.85

4NH cp (mg N l-1) 47 0.33 0.36 9 0.75

3NO wd (µg N m-2) 48 10661 10778 1 0.82

3NO cp (µg N l-1) 48 0.26 0.27 4 0.79

Precipitation 49 44641 45401 2 0.91


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3.2 Nitrogen emissions Table 3.2. Annual total 2014 emissions of nitrogen oxides and ammonia from the HELCOM Contracting Parties and ship traffic on the Baltic Sea. Sum of HELCOM emissions is also included. Units: kt N per year.

Emission source Pollutant

NOx NH3

Denmark 34 60

Estonia 10 11

Finland 42 30

Germany 373 609

Latvia 11 14

Lithuania 16 34

Poland 220 218

Russian Federation 945 769

Sweden 41 44

HELCOM 1692 1791

Baltic Sea 82


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Figure 3.2. Percent of annual emissions of total (oxidised + reduced) nitrogen that is deposited on the Baltic Sea basin in 2014, for HELCOM Parties and international ship traffic on the Baltic Sea (BAS).


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Figure 3.3. Map of annual emissions of oxidised nitrogen (including emissions from the ship traffic) in the Baltic Sea region in 2014. Units: tonnes of NO2 per year and per 50×50 km grid cell.


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Figure 3.4. Map of annual emission of ammonia in the Baltic Sea region in 2014. Units: tonnes of NH3 per year and per 50×50 km grid cell.


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Table 3.2. The list of 11 SNAP emission sectors as specified in the EMEP-CORINAIR Emission Inventory Guidebook.

Sector 1 Combustion in energy and transformation industry

Sector 2 Non-industrial combustion plants Sector 3 Combustion in manufacturing industry

Sector 4 Production processes Sector 5 Extraction and distribution of fossil fuels and geothermal energy

Sector 6 Solvent and other product use Sector 7 Road transport

Sector 8 Other mobile sources and machinery (including ship traffic) Sector 9 Waste treatment and disposal

Sector 10 Agriculture Sector 11 Other sources and sinks


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DENMARK ESTONIA FINLAND

GERMANY

LATVIA

LITHUANIA

POLAND

RUSSIA

SWEDEN

Figure 3.5. Annual 2014 nitrogen oxides emissions from the HELCOM Contracting Parties split into the SNAP sectors.


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DENMARK ESTONIA FINLAND

GERMANY

LATVIA

LITHUANIA

POLAND

RUSSIA

SWEDEN

Figure 3.6. Annual 2014 ammonia emissions from the HELCOM Contracting Parties split into the SNAP sectors.


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Figure 3.7 Map of annual emissions of nitrogen oxides from the international ship traffic on the Baltic Sea in 2014 used in the EMEP model calculations. Units: tonnes of NO2 per year and per 50×50 km grid cell. Emission input data for 2014 was prepared by CEIP.


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3.3 Annual deposition of nitrogen

Figure 3.8. Map of annual deposition of oxidised nitrogen (dry + wet) in 2014.

Units: kg N km-2

yr-1

.


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Figure 3.9. Map of annual deposition of reduced nitrogen (dry + wet) in 2014.

Units: kg N km-2

yr-1

.


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Figure 3.10. Map of annual deposition of total (oxidised + reduced) nitrogen in 2014. Units: kg N km

-2 yr

-1.


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Figure 3.11. Maps of annual precipitation in 2013 and in 2014. Units: mm yr-1

.


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3.4 Normalised annual depositions

Figure 3.12. Normalised deposition of oxidised nitrogen to the Baltic Sea basin for the period 1995-2014. Minimum, maximum and actual annual values of the deposition are also shown. The minimum and maximum annual values are determined by the meteorological conditions for each particular year.


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Figure 3.13. Normalised deposition of reduced nitrogen to the Baltic Sea basin for the period 1995-2014. Minimum, maximum and actual annual values of the deposition are also shown. The minimum and maximum annual values are determined by the meteorological conditions for each particular year.


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Figure 3.14. Normalised deposition of total nitrogen to the Baltic Sea basin for the period 1995-2014. Minimum, maximum and actual annual values of the deposition are also shown. The minimum and maximum annual values are determined by the meteorological conditions for each particular year.


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3.5 Monthly depositions of nitrogen

Figure 3.15. Monthly depositions of oxidised, reduced and total (oxidised + reduced) nitrogen to the entire Baltic Sea basin in 2014. Table 3.4. Values of monthly depositions of oxidised, reduced and total (oxidised + reduced) nitrogen to the entire Baltic Sea basin in 2014. Units: kt N month

-1.

Month Oxidised Reduced Total

January 12.5 7.4 19.8

February 14.4 9.8 24.2

March 7.7 9.0 16.7

April 6.5 8.1 14.6

May 8.5 6.6 15.1

June 7.2 5.6 12.8

July 6.8 4.9 11.7

August 12.4 10.4 22.8

September 8.1 7.2 15.3

October 17.8 15.8 33.6

November 16.7 14.5 31.2

December 12.6 8.8 21.4


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3.6 Comparison with observations As each year, also in 2016 the results of EMEP/MSC-W model were compared with available measurements from the EMEP stations, including HELCOM stations. Here we present a comparison of daily time series of wet deposition of nitrate and ammonia computed by EMEP/MSC-W model with observations for some stations in HELCOM countries where daily observation data were available for the year 2014.

Figure 3.16. Time series of daily wet deposition of Ammonium (left) and Nitrate (right) for the year 2014. The first panel is for the station Lahemaa in Estonia and second panel for Leba in Poland.


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Figure 3.16 (cont.). Time series of daily wet deposition of Ammonium (left) and Nitrate (right) for the year 2014. Results for Raaoe in Sweden.


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3.7 Source allocation of nitrogen deposition

Figure 3.17. Top ten sources with highest contributions of nitrogen emissions to annual deposition of oxidised nitrogen into the Baltic Sea basin in the year 2014. BAS and NOS denote ship emissions form the Baltic Sea and from the North Sea, respectively. RUE denotes the contributions from emissions in extended Russian territory. Results with BAS emissions from the CEIP database above and from FMI below.


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Figure 3.18. Relative top ten contributions of nitrogen emissions to annual deposition of oxidised nitrogen into the Baltic Sea basin in the year 2014. REST denotes remaining emission sources in the EMEP domain. RUE denotes the contributions from emissions in extended Russian territory. Units: % of total deposition of oxidised nitrogen. Results with BAS emissions from the CEIP database above and from FMI below.


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Figure 3.19. Top ten sources with highest contributions of nitrogen emissions to annual deposition of reduced nitrogen into the Baltic Sea basin in the year 2014. BAS and NOS denote ship emissions form the Baltic Sea and from the North Sea, respectively. RUE denotes the contributions from emissions in extended Russian territory.


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Figure 3.20. Relative top ten contributions of nitrogen emissions to annual deposition of reduced nitrogen into the Baltic Sea basin in the year 2014. REST denotes remaining emission sources in the EMEP domain. RUE denotes the contributions from emissions in extended Russian territory. Units: % of total deposition of reduced nitrogen.


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Figure 3.21. Top ten sources with highest contributions of nitrogen emissions to annual deposition of total nitrogen into the Baltic Sea basin in the year 2014. BAS and NOS denote ship emissions form the Baltic Sea and from the North Sea, respectively. RUE denotes the contributions from emissions in extended Russian territory. Results with BAS emissions from CEIP database above and from FMI below.


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Figure 3.22. Relative top ten contributions of nitrogen emissions to annual deposition of total nitrogen into the Baltic Sea basin in the year 2014. REST denotes remaining emission sources in the EMEP domain. RUE denotes the contributions from emissions in extended Russian territory. Units: % of total (oxidised+reduced) nitrogen deposition. Results with BAS emissions from CEIP database above and from FMI below.


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3.8 Conclusions for Chapter 3

Compared to 2013 nitrogen oxides emissions in 2014 are lower (2-9%) in five out of nine HELCOM Contracting Parties with largest reductions in Poland (9%) and Denmark (8%). The HELCOM total emissions from all countries are also 4% lower in 2014. Ship emissions from the Baltic Sea were on the same level in 2013 and 2014 according to CEIP inventory. According to FMI inventory, ship emissions from the Baltic Sea were 1% lower in 2014 than in 2013. The increase of nitrogen oxides emissions between 2013 and 2014 can be noticed in four countries with largest increase in Estonia (12%) and Lithuania (11).

Annual 2014 ammonia emissions in most of the HELCOM CPs remain on the similar level, within 1% range. In two countries, ammonia emissions in 2014 are significantly higher than in 2013. These are Latvia (19%) and Estonia (15%). In case of Germany, ammonia emissions, as used for modelling are 10% higher in 2014 than in 2013, but official ammonia emission from Germany re-submitted to CEIP in 2016 are only 1% higher in 2014.

Among the HELCOM Contracting Parties, the largest percent of 2014 nitrogen emissions deposited to the Baltic Sea basin can be noticed for Denmark (14.6%) and the lowest for Russia (0.6%). Percent of 2014 NO2 emissions from the Baltic ship traffic deposited to the Baltic Sea Basin is high – 14.8%.

There are no major changes in spatial distributions of nitrogen oxides and ammonia emissions in 2014 compared to previous years.

Combustion and transportation SNAP sectors are the main sources of nitrogen oxides emissions, whereas agriculture is the dominating sector for ammonia emissions, for all HELCOM CPs. Not much change over the years.

Calculated annual deposition total nitrogen to the Baltic Sea basin in 2014 was 240 kt. approximately 9% higher than in 2013. Deposition of oxidised nitrogen accounted for 55% of total nitrogen deposition in 2014. The main reason for higher deposition in 2014 is related to meteorological conditions, since nitrogen emission remained on similar level in 2013 and 2014.

Spatial distributions of nitrogen depositions to the Baltic Sea basin in 2014 are similar to those in previous years with a clear gradient south to north.

Normalised depositions of oxidised and total nitrogen to the Baltic Sea basin show decreasing pattern in the period 1995-2014. Normalised depositions of reduced nitrogen are also decreasing, but very little and they are slightly increasing in the last two years. Annual depositions of oxidised nitrogen, as well as wet depositions of nitrogen in the new trend calculated this year are higher than


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in previous years because of a new version of the EMEP/MSC-W model, which better agrees with measurements.

No clear seasonal pattern can be found in monthly nitrogen depositions in 2014. The maximum of the deposition occurs in October and November.

Germany (18%), Poland (13%), ship traffic on the Baltic Sea (12%) and on the North Sea (8%) are the main emission sources contributing to oxidised nitrogen deposition into the Baltic Sea basin in 2014, whereas Germany (29%), Poland (15%), Denmark (10%) and Sweden (7%) are top four sources contributing to reduced nitrogen deposition into the Baltic Sea basin in 2014.

As in previous years, also in 2014 some distant sources like ship traffic on the North Sea (8%), United Kingdom (5%) and. France (4%) contribute significantly to oxidised nitrogen deposition into the Baltic Sea basin.

The main sources contributing to total nitrogen deposition to the Baltic Sea basin are: Germany (23%), Poland (14%), ship traffic on the Baltic Sea (6%), Denmark (6%) and Sweden (5%). Contributions of some distant sources like ship traffic on the North Sea (4%), United Kingdom (4%) and France (4%) are also important.

When FMI inventory is used instead of CEIP inventory for ship emissions from the Baltic Sea, contribution of these emissions to oxidised nitrogen deposition to the Baltic Sea basin is 13% and contribution to total nitrogen deposition 7%. This is 1% more than respective contributions based on the CEIP inventory. Then, ship emissions form the Baltic Sea become the contributor number two after Germany to oxidised nitrogen deposition.

3. atmospheric supply of nitrogen to the baltic sea in 2014 · in this chapter we also show and...

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