IVL Swedish Environmental Research Institute

The potential effect of changing to a nonfossil fuel vehicle fleet was investigated by measuring primary emissions (by extractive sampling of bus plumes) and secondary mass formation, using a Gothenburg Potential Aerosol Mass (Go:PAM) reactor, from 29 in-use transit buses. Regarding fresh emissions, diesel (DSL) buses without a diesel particulate filter (DPF) emitted the highest median mass of particles, whereas compressed natural gas (CNG) buses emitted the lowest (MdEFPM 514 and 11 mg kg fuel–1, respectively).

Rapeseed methyl ester (RME) buses showed smaller MdEFPM and particle sizes than DSL buses. DSL (no DPF) and hybrid-electric RME (RMEHEV) buses exhibited the highest particle numbers (MdEFPN 12 × 1014 # kg fuel–1). RMEHEV buses displayed a significant nucleation mode (Dp< 20 nm). EFPN of CNG buses spanned the highest to lowest values measured. Low MdEFPN and MdEFPM were observed for a DPF-equipped DSL bus.

Secondary particle formation resulting from exhaust aging was generally important for all the buses (79% showed an average EFPM:AGED/EFPM:FRESH ratio >10) and fuel types tested, suggesting an important nonfuel dependent source. The results suggest that the potential for forming secondary mass should be considered in future fuel shifts, since the environmental impact is different when only considering the primary emissions.

IVL Svenska Miljöinstitutet har på uppdrag av Naturvårdsverket undersökt hur stor påverkan utsläpp av ammoniak (NH3) från närliggande jordbruk har på stadsluften i Uppsala, med fokus på halterna av små partiklar (PM2.5) samt potential för utsläpps¬minskningar för att förbättra stadsluften från denna påverkan. Denna fråga är viktig att belysa eftersom utsläppen av NH3 från jordbruket inte förväntas minska i samma takt som utsläpp av andra luftföroreningar. Man har kunnat konstatera, i andra regioner, att det inte bara är viktigt att minska på utsläppen av svavel- och kväveoxider utan att även NH3-utsläppen behöver minskas.

En jämförelse av skillnader i halterna av små partiklar och deras komponenter visar en ökad effekt av jordbruksemissioner av NH3 på vintern, då bidraget ökar från årsmedelvärden på 2,3 % och 1,2 % för regional bakgrund och centrala staden till 3,3 % och 1,6 % för vintermedelvärdet. Skillnaderna mellan säsongerna beror på ett flertal faktorer som exempelvis hur mycket NO3- och SO42- som finns tillgängligt för att bilda partiklar. På vintern är ammoniakutsläppen lägre och NOx- och SOx-utsläppen är relativt sett högre samtidigt som omblandningen är lägre jämfört med övriga delar av året. Detta gör i sin tur att kvoten mellan ammoniak och HNO3 och SO42- är lägre och en större del av ammoniakutsläppen kommer därför att bilda partikelformig NH4+.

Under sommaren är, förutom den högre kvoten mellan NH3 och nitrat och sulfat, även kondensation av nitrat på partiklarna reducerad p.g.a. högre temperaturer vilket begränsar ammoniakens potential att bidra till partiklar ytterligare. Detta innebär att utsläpps¬minskningar av NH3 kan ha större effekt på vintern/hösten med avseende på bildning av sekundära aerosoler än under vår och sommar och kan vara jämförbar med effekten från ytterligare minskningar av SOx- och NOx-utsläpp, även om NH3-utsläppen är högre på våren och sommaren.

The evolution of the different types of Arctic Intermediate Water (AIW) in the Nordic Seas is evaluated and compared utilising hydro-chemical data from 1991 to 2009. It has been suggested that these waters are important components of the Norwegian Sea Arctic Intermediate Water (NSAIW), and of the dense overflows to the North Atlantic. Thus, it is important to understand how their properties and distribution vary with time. The AIWs from the Greenland and Iceland Seas, show different degrees of variability during the studied period; however, only the Greenland Sea Arctic Intermediate Water (GSAIW) shows an increasing temperature and salinity throughout the 2000s, which considerably changed the properties of this water mass.

Optimum multiparameter (OMP) analysis was conducted to assess the sources of the NSAIW. The analysis shows that the Iceland Sea Arctic Intermediate Water (ISAIW) and the GSAIW both contribute to NSAIW, at different densities corresponding to their respective density range. This illustrates that they flow largely isopycnally from their source regions to the Norwegian Sea. The main source of the NSAIW, however, is the upper Polar Deep Water, which explains the lower concentrations of oxygen and chlorofluorocarbons, and higher salinity and nutrient concentrations of the NSAIW layer compared with the ISAIW and GSAIW. This shows how vital it is to include chemical tracers in any water mass analysis to correctly assess the sources of the water mass being studied.

Kontrollprogrammet för Skinnmuddselets reglering har följt utvecklingen av koncentrationen av kvicksilver i vatten och fisk i Skinnmuddselet i nära 30 år, sedan kort efter dämningen och skapandet av regleringsmagasinet 1989.

I kontrollprogrammets mätserier kan man tydligt se att kvicksilverhalten i fisk ökade efter dämningen för att sedan, tillsammans med kvicksilverhalten i vattnet, klinga av och lägga sig på relativt stabila nivåer. 

De första kvicksilvermätningarna i vattnet i Skinnmuddselet gjordes 1992, dvs. ca 3 år efter dämningen. Efter de initialt höga värdena uppmätta under 1992 och 1993 sjönk halten metylkvicksilver under en 10-års-period för att sedan plana ut.

Efter denna period sågs enskilda höga kvicksilverhalter som har kunnat härledas till exempelvis hantering av flyttorv och avrinning efter torrperioder. Andra höga värden kan troligtvis ha orsakats av störningar i marken i avrinningsområdet, exempelvis avverkning eller framförande av tunga maskiner. 

Kvicksilverhalten i fisk undersöktes för 10-cm abborre, 25-cm abborre samt 1-kg gädda. Efter dämningen kunde man se en snabb ökning av kvicksilverhalten för 10-cm abborre i Skinnmuddselet som nådde sitt maximum 1991 (från 0.15 mg/kg till 0.65 mg/kg) följt av en avklingning och stabilisering efter ca 5-7 år.

Även för 1-kg gädda ökade koncentrationerna snabbt, dock inte lika snabbt som för 10-cm abborren utan med sitt maximum 1992 (1.4 mg/kg) och också en längre avklingning av kvicksilverhalten. Efter ca 15-20 år kom kvicksilverhalterna i gädda ner till de halter som uppmättes innan dämning (0.5 mg/kg i Skinnmuddselet).

I Viskasjön, som använts som referens, har kvicksilverhalterna legat stabilt för både abborre och gädda under hela kontrollprogramsperioden.   Ett sidoprojekt genomfördes, där låga doser av selen tillsattes i vatten i området för att undersöka dess effekt på kvicksilver i biota, och detta har sedan följts upp inom kontrollprogrammet.

Selenförsöket i Lavsjön visade tydligt en positiv påverkan av låg-lågdos selenbehandling på kvicksilverhalten i biota med en flerårig minskning av halten metylkvicksilver i abborre och gädda.1994 började flyttorv uppträda i selet. Förutom att större sjok utgör en risk för riksväg 92 och för nedre delen av Skinnmuddselet, sker ofta också en större urlakning av kvicksilver genom den ökade genomsköljningen av torven.

I rapporten sammanfattas de åtgärder som utförts över åren för att hantera flyttorven i syfte att ge så lite påverkan på kvicksilverhalterna som möjligt. 

In this report, pool two ‘Materials & products in industry’ (MP) of the Swedish National Nitrogen Budget (NNB) is presented. The MP pool of NNB is one of the eight major pools defined by the Task Force of Reactive Nitrogen (TFRN) which together represent a total national nitrogen budget capturing all major flows of all forms of reactive nitrogen (Nr) within a country and across the country borders. The methodology to calculate NNB has been provided by the Expert Panel on Nitrogen Budgets (EPNB) in the Annexes to the ECE/EB.AIR/119 – “Guidance document on national nitrogen budgets".The three most important sources of data were Statistics Sweden (SCB), The Swedish Board of Agriculture (Jordbruksverket) and Swedish Chemicals Agency (Kemikalieinspektionen).

Data on some chemicals were seen as industrial secrets or - in case of e.g. explosives – as non-public data. The major flows of Nr to and from MP, were when possible calculated for the year 2015. The MP pool is dominated by Nr flows associated with chemicals, food and feed. These flows are between MP pool and pools ‘Rest of the world’ (i.e. outside Sweden), ‘Agriculture’ and ‘Humans & settlements’. The total input of reactive nitrogen to MP was 696 kt N and the outputs 636 kt N. Of the eight pools considered in a complete national N budget, the MP pool is rather central. MP has the largest flows of Nr in and out of the pool and it includes the major Nr flows associated with import and export of chemicals, products to and from the pool Agriculture, and Nr flows to the pool Humans and settlements.

En kartläggning av nedfall av kväve och svavel i Norrbottens län, på uppdrag av Länsstyrelsen i Norbottens län.

This report describes the flow of reactive nitrogen for forests and semi-natural vegetation in Sweden according to the methodology developed within the framework of the Task Force on Reactive Nitrogen (TFRN). Forest and semi-natural vegetation (FS) constitute one out of 8 pools for the Swedish National Nitrogen Budget. The FS pool is divided into the three compartments; forest, wetland and other land. Together they amount to 71% of the country area.

The data used has been collected from Swedish official statistics and reports and are representative for year 2015 whenever possible.

In total, the FS pool has inflows of reactive nitrogen of 175.8 kilotonnes (kt) and outflows of 188.6 kt. The largest inflow is from atmospheric deposition (99.3 kt) and the largest outflow is via leaching/runoff (67.4 kt). Forestry is a major industry in Sweden and the nitrogen flow from the forest due to harvest is the second largest outflow from the FS-pool (58.5 kt). Biological fixation of nitrogen is an important inflow for both forest (39.5 kt) and wetland (32.1 kt). Other land (which mostly consists of mountains) is of smaller quantitative importance and only has two flows: leaching/runoff and deposition (2.9 kt N and 2.9 kt N, respectively).

This report presents pool ‘Humans and settlement’ of the Swedish National Nitrogen Budget (NNB), one of the eight major pools defined by the Task Force on Reactive Nitrogen within the Air Convention (CLRTAP). A complete NNB captures all major flows of all forms of reactive nitrogen (Nr) within a country and across the country borders. In the ‘Humans and settlement’ pool the largest flows of Nr are associated with imported and produced products, food and discarded waste, mainly material waste.

In this report, pool 7 ‘Atmosphere’ (AT) of the Swedish National Nitrogen Budget (NNB) is presented.

The atmospheric pool of NNB is one of the 8 major pools defined by the Task Force of Reactive Nitrogen (TFRN) which together represent a total national nitrogen budget capturing all major flows of all forms of reactive nitrogen (Nr) within a country and across the country borders.

The methodology to calculate NNB has been provided by the Expert Panel on Nitrogen Budgets (EPNB) in the Annexes to the ECE/EB.AIR/119 – “Guidance document on national nitrogen budgets".

The major flows of Nr to and from the tropospheric air masses above Sweden, including the Swedish national coastal waters, were calculated for the year 2015. Except for the small amount of Nr generated by lightnings, the atmospheric Nr pool is dominated by four main flows: the import and export of Nr by transboundary transport; by Swedish emissions of Nr; and by atmospheric deposition. 

The principal source of the emission data has been the official Swedish reporting to the Centre on Emission Inventories and Projections (CEIP) under the Air convention (The Convention on Long-range Transboundary Air Pollution, CLRTAP).

For the reactive nitrogen deposition in Sweden the official national operational estimates by the MATCH Sweden system were used.

The results show that in 2015 Sweden was a net importer of air pollution in the form of Nr, i.e. the import of Nr from the emission sources outside the country (139 kt N) was larger than the export (96.1 kt N).

The Swedish emissions of Nr in 2015 were in total 117 kt N. The largest emissions come from two sectors: Agriculture (43.4 kt N) and Energy & Fuels (40.6 kt N). The deposition of Nr to Swedish ecosystems in 2015 was 160 kt N, of which 87% originated from emission sources abroad.

Chronic high deposition of nitrogen (N) to forest ecosystems can lead to increased leaching of inorganic N to surface waters, enhancing acidification and eutrophication. For 26 years nitrogen has been added as ammonium nitrate (NH4NO3) at 40kgN ha-1 yr-1 to a whole forested catchment ecosystem at Gårdsjön, Sweden, to experimentally simulate the transition from a N-limited to N-rich state.

Over the first 10 years of treatment there was an increasing amount of nitrate (NO3-) and to a lesser extent ammonium (NH4+) lost in runoff, but then N leaching stabilised, and for the subsequent 16 years the fraction of N added lost in runoff remained at 9%. NO3- concentrations in runoff were low in the summer during the first years of treatment, but now are high throughout the year. High frequency sampling showed that peaks in NO3- concentrations generally occurred with high discharge, and were enhanced if high discharge coincided with occasions of N addition.

Approximately 50% of the added N has gone to the soil. The added N is equivalent to 140 years of ambient N deposition. At current ambient levels of N deposition there thus appears to be no immediate risk of N saturation at this coniferous forest ecosystem, and by inference to other such N-limited forests in Scandinavia.

Kapaciteten att hantera vatten och partiklar vid ett kraftigt punktutsläpp (så kallad bräddning) i en dag- och bräddvattenanläggning har testats i ett fullskaleförsök. En tankbil släppte ut 9 kubikmeter rent vatten med mikroplast, 2 g polyamidpartiklar, i en grop överst i anläggningen. Vattenprover samlades in och filtrerades och partiklarna analyserades i mikroskop. Anläggningen fördröjde effektivt det insläppta vattnet och partikelhalterna minskade mycket kraftigt mellan utsläppet och anläggningens olika delar.

Denna rapport redovisar resultat från projektet ”Effekten av sjöfartens utsläpp av svavel och kväve på överskridande av kritisk belastning för försurning och för övergödning i Sverige”, Naturvårdsverkets ärendenummer NV-07751-17. Projektet bygger på ett antal utsläppscenarier med fokus på olika sjöfartsemissionsscenarier. Dessa scenarier har tagits fram inom BONUS SHEBA (Sustainable shipping and Environment of the Baltic Sea region) projektet för åren 2012 och 2040. Rapporten visar hur överskridandet av kritisk belastning för försurning och eutrofiering i Sverige påverkas av sjöfarten.

This report presents the results of a project undertaken by Norway, Finland, Sweden, and Denmark related to the National Nitrogen Budget (NNB) with a focus on the NNB pool Forests and semi-natural vegetation (FS). The NNB involves calculations of reactive nitrogen (Nr) inflows and outflows within the FS pool, and the study compares these calculations to reports of carbon sequestration in climate reporting to the United Nations Framework Convention on Climate Change (UNFCCC).Norway and Finland initiated their work on NNB, concentrating on Forests and semi-natural vegetation (FS). The UNECE LRTAP Task Force on Reactive Nitrogen (TFRN) methodology was also used for compiling the FS pool for Denmark, while Sweden had established its FS pool prior to the project.The FS pool comprises three sub-pools: forests, wetlands, and other lands. Inflows of reactive nitrogen (Nr) to the FS pool are primarily from deposition and biological N-fixation, with major outflows being leaching, harvest, and denitrification.In Finland, Sweden, and Denmark, the inflows and outflows are in balance, while in Norway, there is an accumulation of Nr, indicating a surplus of nitrogen. Wetland sub-pools in all four countries and the forest sub-pool in Norway show nitrogen accumulation.All four countries report carbon sequestration in forests to UNFCCC.

There is a link between nitrogen and carbon cycles, since the organic matter forming the carbon stock in forests and wetlands relies on nitrogen. The origin of nitrogen contributing to the estimated C-stock increase needs further investigation.There is a discrepancy between the calculated nitrogen changes in the FS pool and the nitrogen needed to support reported carbon stock changes. Possible explanations for the discrepancies are re-location of nitrogen within pools, changes in the C/N ratio, expansion of forested areas, and uncertainties in N-fixation rates and denitrification.There is a need for better integration of carbon and nitrogen flux and stock change estimates in natural ecosystems. Understanding the interactions between carbon and nitrogen is deemed crucial for predicting future developments in carbon sequestration and impacts of nitrogen deposition, especially for the Nordic countries with their significant forests playing roles as carbon and nitrogen sinks.

The MAGIC library is an acidification assessment tool that allows lakes and watercourses to be assessed with a similar water. In this way, tens of thousands of lakes and watercourses have been assessed. In connection with these assessments, a number of cases have been identified where the calculated reference values have been judged to be unrealistic based on other knowledge that the users of the MAGIC library possess. Administrators at the county administrative boards responsible for liming, were requested to send in documentation on such objects where the acidification assessment with the MAGIC library was considered incorrect. As much relevant background information as possible was requested so that explanations for the different assessments could be investigated. Eight county administrative boards responded to the query. Based on the collected material, MAGIC (Model of Acidification of Groundwater in Catchments) -modeled objects and MAGIC library results were compared with historical fish data, with measured water chemistry including trends over time and a comparison with measured and modeled atmospheric precipitation was made.

The study compared the occurrence of roaches from the end of the 19th century in Värmland with modeled water chemistry. Roaches were found in most of the lakes, including lakes with a low modeled pH. However, there is a clearly decreasing proportion of lakes with the occurrence of roaches the lower the modeled pH of the waters. This is in contrast to, for example, the much less acid-sensitive perch where no connection between occurrence and historically modeled pH could be discerned. Lakes with low pH and where roach occurred at the end of the 19th century have on average a higher content of dissolved organic carbon than lakes with higher pH.

A comparison between measured time series from lakes and modeled values for the same lake in the MAGIC library shows that the magnitude of the modeled trend in many cases is larger than the observed trend. The picture is not entirely unambiguous, and the differences are greater for sulphate than for ANC (acid neutralizing ability), but that the model overestimates the trend occurs much more often than the other way around. This is largely due to the fact that there is a tendency for the model to overestimate the sulphate content in the lakes at the beginning of the measurements. The reason for this can vary, but correct modeling of time trends in the runoff presupposes that the time development of the deposition of sulfur, nitrogen and base cations used in the modeling has followed reality.

Acrossmuch of the northern hemisphere, lakes are at risk of re-acidification due to incomplete recovery fromhistorical acidification and pressures associated withmore intensive forest biomass harvesting. Critical load (CL) calculations aimed at estimating the amount of pollutants an ecosystem can receive without suffering adverse consequences are dependent on these factors. Here, we present a modelling study of the potential effects of intensified forest harvesting on re-acidification of a set of 3239 Swedish lakes based on scenarios with varying intensities of forest biomass harvest and acid deposition. There is some evidence that forestrywould have caused a certain level of acidification even if deposition remained at 1860 levels. We show that all plausible harvest scenarios delay recovery due to increased rates of base cation removal. Scenario resultswere used to estimate critical loads for the entire population of lakes in Sweden. The forestry intensity included in critical load calculations is a political decision. After scaling calculations to the national level, it was apparent that a high but plausible forest harvest intensity would lead to an increase in the area of CL exceedances and that even after significant reductions in forest harvest intensity, there would still be areas with CL exceedances. Our results show that forest harvest intensity and regional environmental change must be carefully considered in future CL calculations.

We have developed a tool, the MAGIC library, which provides an acidification assessment for any given lake or stream in Sweden based on ten parameters describing lake geographical position, surface area, annual discharge and observed lake water chemistry. The MAGIC library consists of two key components: a library of the existing MAGIC model simulations for 2438 lakes and an analogue matching routine that selects the library lake which is most similar to the evaluation lake described by the ten parameters. The acidification assessment modelled by MAGIC for the library lake is then assumed valid for the evaluation lake. For more than 90% of the library lakes tested, the MAGIC library provided the same acidification assessment as the site-specific MAGIC model simulation. Labour and data requirements for assessment by the MAGIC library are very modest relative to the needs of site-specific MAGIC (or other similar) model simulations. The relative ease of use is essential for a country like Sweden, with a population of 100 000 lakes. The MAGIC library has a web interface (http://magicbiblioteket.ivl. se) to provide single assessments interactively or multiple assessments by uploading the ten required parameters for multiple sites. Conceptually the library has built-in flexibility and could be adapted for other types of ecosystems or assessments. In this paper we describe the MAGIC library concept and evaluate the performance of the MAGIC library in comparison to site-specific MAGIC modelling.

The most important parameters that influence the air quality in vehicles are the choice of cabin air filter and the air quality outside the vehicle. Real-life driving test methods for measurement in traffic environments developed in AQIFOR project showed repeatable differences between the reduction efficiency of the various cabin air filters in the car ventilation systems. Additional parameters that affected the reduction efficiency for air pollutants in the vehicle were ventilation speed and degree of air recirculation in the ventilation. Different air pollutants are affected differently. All filters tested purified air from particles; the reduction efficiency for PM2.5 was from 40% to over 80% for different filters, particles in the size range 10 - 600 nm were more difficult to clean than larger particles. Filters containing active carbon also purified the air from NO2; reduction efficiency showed similar pattern to reduction efficiency for particles. Sampling for VOC and PAH showed that volatiles are not purified by filters, but the less volatile species are effectively reduced. The project also investigated occupational exposure of professional drivers to air pollution in both passenger cars and trucks. The results showed that the drivers' exposure to benzo (a) pyrene, 1,3-butadiene and benzene was low, well below the working environment limit values.

Forskningsprogrammet CLEO, Climate change and Environmental Objectives, startades 2010 efter en utlysning från Naturvårdsverket där man efterfrågade forskning med en övergripande målsättning att få: * En analys och kvantifiering av hur förändringar i klimatet, såsom temperatur, nederbörd och avrinning, påverkar förutsättningarna att nå de miljömål som påverkas av långväga transporterade luftföroreningar * En beskrivning och analys av synergier och målkonflikter av åtgärder, både nationellt och internationellt, för att minska utsläpp av växthusgaser och andra luftföroreningar för att nå uppsatta miljömål. * Förbättrad kunskap om grundläggande processer för att ta fram tillförlitliga prognoser och scenarier för utvecklingen mot miljömålen, förbättrade indata till existerande modeller samt bättre sammanlänkning av modeller för klimat, luft och ekosystem.

Programmet har fokuserat på miljömålen Frisk luft, Bara Naturlig Försurning, Ingen övergödning och i viss mån Giftfri miljö. Då målsättningen var att ta fram resultat som är relevanta för pågående arbete med miljömålen och för långsiktiga överväganden så har CLEO arbetat med framtidsscenarier som både fokuserat på en relativt nära framtid (2030), och i vissa avseenden ett längre tidsperspektiv (2100).

This report is only available in Swedish. English summary is available in the report.

This report is only available in Swedish.

This report is only available in Swedish.

European ecosystems have been subject to extensiveshifts in anthropogenic disturbance, primarilythrough atmospheric deposition, climate change,and land management. 

These changes have alteredthe macronutrient composition of aquatic systems,with widespread increases in organic carbon (C),and declines in nitrogen (N) and phosphorus (P).Less well known is how these disturbances haveaffected nutrient stoichiometry, which may be amore useful metric to evaluate the health ofaquatic ecosystems than individual nutrient concentrations.

The Swedish west coast has historicallyexperienced moderate to high levels of atmosphericdeposition of sulfate and N, and eutrophication. Inaddition, coastal waters have been darkening withdamaging effects on marine flora and fauna.

Here,we present three decades of macronutrient datafrom twenty lakes and watercourses along the Swedish west coast, extending from headwaters toriver mouths, across a range of land covers, andwith catchments ranging 0.037–40,000 km2. Wefind a high degree of consistency between thesediverse sites, with widespread increasing trends inorganic C, and declines in inorganic N and total P.

These trends in individual macronutrients translateinto large stoichiometric changes, with a doublingin C:P, and increases in C:N and N:P by 50% and30%, showing that freshwaters are moving furtheraway from the Redfield Ratio, and becoming evenmore C rich, and depleted in N and P.

Althoughrecovery from atmospheric deposition is linked tosome of these changes, land cover also appears tohave an effect; lakes buffer against C increases, anddecreases in inorganic N have been greatest underarable land cover. Our analysis also detects coherentlydeclining P concentrations in small forestlakes; so called (and unexplained) ‘‘oligotrophication.’’

Taken together, our findings show thatfreshwater macronutrient concentrations and stoichiometryhave undergone substantial shifts duringthe last three decades, and these shifts can potentiallyexplain some of the detrimental changes thatadjacent coastal ecosystems are undergoing.

Ourfindings are relevant for all European and NorthAmerican waters that have experienced historicallyhigh levels of atmospheric deposition, and provide a starting point for understanding and mitigating against the trajectories of long-term change in aquatic systems.

Excessive amounts of reactive nitrogen (Nr) in the hydrosphere can impair water quality and alter the functioning of aquatic ecosystems. Monitoring of water bodies and awareness of the existing flows of nitrogen from different sectors in society can support policy making. In this report we quantified the major flows of Nr in the Hydrosphere pool of the Swedish National Nitrogen Budget, according to the methodology provided by the Task Force on Reactive Nitrogen. Calculations were done for one full year using data mainly from 2014 but also from 2015.

In 2014/2015, the largest inflows of Nr to the Swedish hydrosphere were leaching from agriculture (53 kilotonnes, kt), from forests (48 kt), atmospheric deposition (33 kt), leaching from wetlands and other land (20 kt) and municipal wastewater treatment plants (17 kt). In addition, there were minor contributions from industrial wastewaters, small dwellings and from stormwater runoff. The major outflows were transport from the coastal waters to the open sea and marine denitrification (together 127 kt) and denitrification from freshwaters (34 kt) N. In addition, there were quantitatively less important Nr losses through fishing, N2O emissions and water abstraction.

Data come from Svenska MiljöEmissionsData, Statistics Sweden, Nationellt vattentäktsarkiv and SMHI.

This report presents pool 1 “Energy and fuels” (EF) in the Swedish national nitrogen budget (NNB). The EF pool is divided into four sub-pools; Energy conversion (EC), Manufacturing industries and construction (IC), Transport (TR) and Other energy and fuels (OE).

The Swedish data presented in this report are for 2015 whenever possible. If data were not available for 2015, available information for the year closest to 2015 have been used. The data were collected from Swedish official statistics and reports and preferably from sources that will continue to be updated, to make it easier to evaluate possible changes in N budgets in the future.

Emissions of reactive nitrogen (Nr) to the atmosphere via various combustion processes have been quantified as they have been reported to international conventions (CLRTAP and UNFCCC) broken down by the codes used in those reports. 

The largest emissions of Nr occur from transport (24.1 kt), followed by manufacturing and construction (6.7 kt), other energy and fuels (4.9 kt) and energy conversion (4.8 kt). The majority of reactive nitrogen emissions from this sector (> 90 percent) consists of NOx, and otherwise of N2O and NH3.

The import of primarily crude oil and of other oil-based fuels means a flow of N from the rest of the world to Sweden (53.5 kt). A fraction of this amount is converted to reactive forms and emitted to the atmosphere during combustion. The main part of the NOx that is emitted from fuel combustion is, however, formed when nitrogen in the air is oxidized during the combustion (thermal production of NOx) and does not originate from the N in the fuel. Remaining N in the crude oil and oil products is either removed from the fuel during cracking in refineries or converted to N2 during combustion. Development of combustion processes where NOx is not formed leads to lower emissions.  Biofuels such as ethanol and biodiesel are produced from e.g. wheat and rapeseed. A large part of the nitrogen present in these crops will remain in the residual products after fuel production and can be used for animal feed. They do not result in any emissions of reactive nitrogen in this national nitrogen budget.

The national nitrogen budgets do not include international transport (shipping, aviation), so additional emissions of reactive nitrogen will need to be added if a global aggregation is to be made.

Denna rapport sammanfattar de svenska studier som har undersökt hur halten av löst organiskt kol (DOC) i våra vatten förändrats över tid. De trender som visats i övervakningsdata från de senaste ca 30 åren redovisas också. Syftet är att sammanställa vilka processer eller mekanismer som har påverkat DOC-halten och att uppskatta betydelsen av detta för bedömning av försurning för att på sikt ytterligare förbättra försurningsbedömningarna i svenska sjöar och vattendrag. Bedömning av försurningsstatus för en sjö eller ett vattendrag i Sverige görs antingen direkt genom modellering med MAGIC (Model of Acidification of Groundwater In Catchments) eller indirekt genom att ett antal parametrar matas in i verktyget MAGIC-biblioteket (magicbiblioteket.ivl.se) som ger en bedömning.

Ett antal studier har ett experimentellt upplägg, till exempel studeras hur DOC-halten över året skiljer sig åt i avrinningsområden med varierande andel skog och våtmark och hur tillsatser av försurande ämnen påverkar. Andra studier använder data som samlats in via miljöövervakningen för ett stort antal sjöar under de senaste decennierna.

Sedimentdata från ett urval av sjöar har studerats med metoden VNIRS (visible near-infrared spectroscopy) för att identifiera halten totalt organisk kol (TOC, i stort sett enbart bestående av DOC) över längre tidsperioder, i vissa fall flera tusen år. Dessa mätningar visar att DOC-halten sedan den senaste istiden ofta varit högre än idag. Nedgången i TOC-halt under 1900-talet har i flera studier förklarats som en påverkan av det höga svavelnedfall som skedde under framför allt mitten till slutet av 1900-talet. Förändringar i markanvändning och klimat är andra förklaringsmodeller.

Dagens försurningsbedömningar, där en förändring i pH från 1860 till idag uppskattas och en minskning i pH med mer än 0,4 pH-enheter anses innebära att sjön eller vattendraget är påverkat av försurning, bygger på att pH-värdet år 1860 kan uppskattas på ett tillförlitligt sätt. I denna rapport diskuteras DOC-haltens inverkan på bedömningen.

To better understand the magnitude of reactive nitrogen flows in a country, a national nitrogen budget can be constructed. In this report, we use a methodology developed by the Expert Panel on Nitrogen Budgets (EPNB) under the Task Force for Reactive Nitrogen (TFRN) and describe the flows of nitrogen in agriculture in Sweden in 2015.

The primary source of data presented in this report are data reported to Eurostat and UNFCCC regarding gross nutrient balance and greenhouse gases. The flows of nitrogen not covered by Eurostat and UNFCCC originate from for example the national compilations of content of feed products and slaughtering weight of animals for consumption.

The largest inputs of nitrogen to agriculture are in the form of supply of inorganic fertilizer to soil (190 kT) and feed to animals (59 kT). The largest outputs of nitrogen are in the form of products for consumers (eg crops, meat, milk, eggs) (171 kT) and emissions to the hydrosphere and atmosphere (93 kT).

In total, the inputs were 15 percent larger than the outputs, which is well within the differences found in other countries. The difference may be due to uncertainties in the collected data or that further flows may occur. Such flows should be identified and investigated in the future. The difference may also indicate that the pool of nitrogen in agriculture is not in balance, i.e. nitrogen is stored in the soil.