IVL Swedish Environmental Research Institute

On behalf of the Swedish Environmental Protection Agency, IVL Swedish Environmental Research Institute led in 2015 a project aiming to examine the concentrations of persistent organic pollutants (POPs) in mosses.
Samples of red-stemmed feathermoss (Pleurozium schreberi) and glittering wood moss (Hylocomium splendens) were collected at 83 rural sampling sites. Of these, 20 samples were analysed for the following groups: polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), selected organochlorine pesticides, polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), dioxins and furans (PCDD/PCDFs), dioxin-like PCBs and perfluorinated alkylated substances (PFAS).
The sampling sites were selected to cover the whole of Sweden, in both the north-south gradient and in the east-west gradient. The sites were also chosen to represent both eventually elevated concentrations as well as low concentrations of POPs. Information on locations of industrial activities, population density and monitoring stations for organic substances in air and precipitation (Swedish national monitoring programme) were also used for the selection of sampling sites.
Generally, the concentrations of the analysed substances were very low, often close to or below the quantification limits for the analyses.
Significant correlation was found between the concentrations of PAHs, dioxin/furans and dioxin like PCBs in the mosses and the distance to the closest industry, and also to the distance from the southernmost point in Sweden. p,p-DDE concentrations in mosses showed a correlation to the distance from the southernmost point in Sweden, with the highest concentrations in the south. No correlation was found between the concentrations of p,p-DDE (one of the DDTs) in mosses and distance to the closest industry.
The concentrations of PAHs in mosses collected at sites located in the vicinity of three air monitoring stations (Råö, Aspvreten and Pallas) were in agreement with the concentrations of PAHs in air, with the highest concentrations in mosses and in air found in the south and the lowest in the north. Comparison between the PAH profile in air and in mosses showed a higher percentage of heavier PAHs in the mosses. This indicates a larger proportion of particular bounded PAHs in mosses.
HBCDD and PFAS were not detected in any of the analysed moss samples, which is consistent with a similar study conducted in Norway.

Naturvårdsverket ansvarar för den nationella övervakningen av luftens och nederbördens kvalitet i bakgrundsmiljö. I rapporten redovisas resultat från verksamheten inom Programområde Luft avseende mätningar till och med 2017 och regionala modellberäkningar till och med 2016, respektive 2017 för marknära ozon.

Naturvårdsverket, Luftenheten, ansvarar för den nationella luftövervakningen i bakgrundsmiljö. I rapporten redovisas resultat från verksamheten inom Programområde Luft avseende mätningar (genomförda av IVL, SU, SLU och SMHI) till och med 2019 och regionala modellberäkningar (utförda av SMHI) till och med 2018. 

The Swedish Environmental Protection Agency is responsible for the national air quality and precipitation monitoring in rural background areas.

This report presents the results from the activities within the National monitoring programme for air pollutants including measurements (performed by IVL Swedish Environmental Research Institute (IVL), Stockholm University (SU), Swedish University of Agricultural Sciences (SLU), Chalmers University of Technology and Swedish Meteorological and Hydrological Institute (SMHI) respectively) until 2021 and modelling (performed by SMHI) until 2020

.For most of the air pollutants monitored the situation has improved significantly since the measurements started between 20 and 40 years back, regarding air concentrations as well as deposition in the rural background.

The pollution load is in general decreasing the further north one goes.For most of the components for which there are environmental quality standards (EQS) and environmental objectives, the concentrations are well below the limit and target values.

The concentrations of ground-level ozone exceed the air quality standard for health at several locations in southern Sweden. For particles (PM2,5) and benzene (in urban background air) there is a low risk for concentration levels above the specifications of the environmental objectives.

IVL Swedish Environmental Research Institute has performed a 'Screening Study' of difenacoum and related compounds as an assignment from the Swedish Environmental Protection Agency. Difenacoum is used as a second generation anticoagulant rodenticides (SGAR). It is mainly used to control rodents around buildings and inside transport vehicles. Difenacoum is uptaken via ingestion and acts by disrupting the blood clotting process. In addition to difenacoum, the current study also includes another six substances with similar functions. The overall objectives of the study were to determine the concentrations of the selected substances in the Swedish environment. A sampling programme was developed and 60 samples were included in the study, representing surface water, sediment, fish, soil, in- and effluent water from sewage treatment plants, sludge, storm water, storm water and sludge, and eagle-owl tissues. All of the seven anticoagulant rodenticides were below detection limit in all abiotic samples and in fish. This shows that these substances are not widely distributed in the Swedish environment. However, difenacoum and three of the related compounds (coumatetralyl, bromadiolone and bromadifacoum) were found in three of the eagle-owl individuals. Coumatetralyl and bromadiolone were found in highest levels followed by difenacoum and the liver sampled contained higher concentrations compared to muscle samples. This shows that secondary poisoning of animals feeding on rodents not can be excluded. Additional studies focusing on areas with known usage could reveal if other non-target organisms other than eagle-owls are likely to be exposed to rodenticides. The study also confirms that the liver is the main target for retention of these rodenticdes.Version 2 april 2012

Syftet med projektet var att förbättra underlaget för framtida beräkningar av årliga emissioner från småskalig vedeldning i villor genom att dels mäta emissioner hemma hos dem som eldar med ved i braskaminer och spisinsatser, dels genom en enkätstudie undersöka hur ofta och på vilket sätt lokaleldstäder (kaminer, spisinsatser, öppen spis etc) eldas i Sverige. Procentuellt för alla regioner var fördelningen mellan olika slags lokaleldstäder: 44 % braskaminer, 23 % öppen spis, 23 % öppen spis med insats ,14 % värmeackumulerade ugnar och 12 % köksspisar (Summan av procenten blir inte 100 % eftersom en del fastigheter har flera olika typer av eldstäder) Mer än hälften av alla lokaleldstäderna var installerade före 1991. Uppmätta emissioner visade liten skillnad mellan kaminer och spisinsatser. Spisinsatserna hade något högre medelvärde för OGC, metan, NMVOC och stoft. Lägst emissioner hade de nya kaminerna och spisinsatserna med undantag av två fall. Emissionsdata varierade mellan 750-4700 mg/MJ för CO, 50-440 mg/MJ för OGC, 11-230 mg/MJ för metan, 20-260 mg/MJ för NMVOC, 0,5-17 mg/MJ för PAH och 20-180 mg/MJ för stoft.

This report has been written as part of the project Grön BoStad Stockholm, which is funded by the European Regional Development Fund. The project has been performed by IVL Swedish Environmental Research Institute.

IVL Swedish Environmental Institute has, together with CleanBioHeat AB, conducted measurements of flue gas condensate from a pellet-fired boiler equipped with Flue Gas Recovery Unit (FGR) for flue gas cleaning and increased heat recovery. In a previous study of similar boilers and FGR high concentrations of some metals were measured in the flue gas condensate, whereby an additional purification step, an ion exchanger, was introduced in a new installation. In this study, the presence of toxic compounds was analyzed both before and after the ion exchanger.

The purpose of the measurements was to provide a basis of analysis data for assessing the possibility of releasing the condensate to the water recipient via the urban stormwater, primarily for the boiler and FGR equipped with ion exchanger, but also to contribute to a larger base of measurements that can be used for future installations of the technology.

In the report the technology of the FGR is briefly described and measurement methods and results are reported. Comparisons between measured concentrations and limit values for surface water according to the EU: s so called water directive and guideline values for emissions to stormwater systems and recipients are made. The conclusion from the investigations of this boiler with FGR is that neither PAH, metals, pH nor TOC should cause any obstacle to the emission of the flue gas condensate directly to the water recipient. This is evidenced by the fact that Microtox analysis did not detect any toxicity either before or after the ion exchanger.

In the case of the nutrients nitrogen and phosphorus, the concentrations in the flue gas condensate were higher than the guideline values for what can be released to stormwater according to three of the major instances who have issued guidelines; Northwest Skåne, the Gothenburg Environmental Management and the regional stormwater network in Stockholm County.

Measurements of the terpene limonene were performed in 223 samples of air, sediment, sludge, water and biota from background and urban sites and from point sources. Both of the two optical isomers, d-limonene and l-limonene, were analyzed in all media. Since limonene is emitted from several plants, such as pine, it occurs naturally in the environment but is also used in houshold products and industrially. Air samples from industrial point sources indicated local emissions but limonene degrades quickly in the atmosphere. None of the background sediments and only two of the background water samples contained detectable concentrations of limonene. No limonene was detected in biota (fish) and the conclusion of the screening is that accumulation of limonene in the environment is of minor importance.

Methyl tert-butyl ether (MTBE) and ethyl tert-butyl ether (ETBE) are mainly used as additives to gasoline in order to enhance the combustion efficiency. As an assignment from the Swedish Environmental Protection Agency, IVL has performed a screening study of MTBE and ETBE. The overall objective of the screening was to determine concentrations in a variety of media in the Swedish environment, in order to judge if the substances are commonly occurring in the Swedish environment. A further aim was to determine key sources and highlight major transport routes

Naturvårdsverket, Enheten för luft och klimat, ansvarar för den nationella övervakningen av luftens och nederbördens kvalitet i bakgrundsmiljö. I rapporten redovisas resultat från verksamheten inom Programområde Luft avseende mätningar (genomförda av IVL, SU, SLU och SMHI) till och med 2015 och regionala modellberäkningar (utförda av SMHI) till och med 2014, respektive 2015 för marknära ozon. Den nationella luftövervakningen omfattar även viss mätverksamhet på Svalbard, men denna redovisas inte i föreliggande rapport. Den 1 januari 2016 flyttades verksamheten vid EMEP-stationen Vavihill, på Söderåsen i Skåne, till Hallahus, 1 km norr om den tidigare mätplatsen.

För flertalet av de luftföroreningskomponenter som övervakas inom den nationella miljöövervakningen har det, sedan mätningarna startade för mellan 15 och 35 år sedan, generellt skett en avsevärd förbättring avseende såväl halter i luft som deposition i bakgrundsmiljö. Utvecklingen har dock varierat i något olika utsträckning beroende på komponenter och lokalisering i landet. Föroreningsbelastningen är oftast lägre ju längre norrut man kommer.

För de flesta ämnen som det finns miljökvalitetsnormer (MKN) respektive miljömål för ligger halterna avsevärt lägre än angivna gräns- och målvärden. Halterna av ozon överskrider i dagsläget MKN för hälsa. För såväl marknära ozon, partiklar (i form av PM2.5) och bensen (i urban bakgrund) finns risk för haltnivåer som överstiger miljömålens preciseringar.

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

The Swedish Environmental Protection Agency, the unit for Air Quality and Climate Change, is responsible for the national air quality and precipitation monitoring in rural background areas. The report presents the results from the activities within the National monitoring progamme for air pollutants regarding measurements (performed by IVL, ITM and SLU respectively) until 2013 and modelling (performed by SMHI) under 2012. This report is only available in Swedish.

På uppdrag av Naturvårdsverket, Enheten för luft och klimat, bedrivs mätningar av luftens och nederbördens sammansättning, främst i bakgrundsmiljö, inom olika mätprogram. IVL Svenska Miljöinstitutet har ansvar för genomförandet av merparten av verksamheten inom luftområdet. Därtill ombesörjer både Institutionen för Tillämpad Miljöteknik (ITM) vid Stockholms universitet och Institutionen för Mark och Miljö vid Sveriges lantbruks-universitet (SLU) delar av övervakningen. SMHI genomför, med hjälp av beräknings-modeller, en geografisk kartläggning av halter i luft och deposition av försurande och övergödande ämnen på nationell nivå. De samlade resultaten från mätningar till och med 2011 och beräkningar till och med 2010 redovisas i denna rapport. Det har generellt sett skett en avsevärd förbättring avseende såväl halter i luft som deposition i bakgrundsmiljö för flertalet av de luftförorenings-komponenter som övervakas inom den nationella miljöövervakningen sedan mätningarna startade för mellan 10 och 30 år sedan. Utvecklingen har dock varierat i något olika utsträckning beroende på komponent och lokalisering i landet. Föroreningsbelastningen är oftast lägre ju längre norrut man kommer. För de flesta de ämnen som det finns miljökvalitetsnormer (MKN) respektive miljömål för ligger halterna avsevärt lägre än angivna gräns- och målvärden. Halterna av ozon överskrider i dagsläget MKN för hälsa. För såväl ozon som för bensen (i urban bakgrund) finns risk för haltnivåer som överstiger miljömålens preciseringar.

På uppdrag av Naturvårdsverkets Miljöövervakningsenhet bedrivs mätningar av luftens och nederbördens sammansättning, främst i bakgrundsmiljö, inom olika mätprogram. IVL Svenska Miljöinstitutet har ansvar för genomförandet av merparten av verksamheten inom luftområdet. Därtill ombesörjer både Institutionen för Tillämpad Miljöteknik (ITM) vid Stockholms universitet och Institutionen för Mark och Miljö vid Sveriges lantbruksuniversitet (SLU) delar av övervakningen. De samlade resultaten från mätningarna till och med 2009 redovisas i denna rapport. Det har generellt sett skett en avsevärd förbättring avseende såväl halter i luft som deposition i bakgrundsmiljö för flertalet av de luftföroreningskomponenter som övervakas inom den nationella miljöövervakningen sedan mätningarna startade för mellan 10 och 30 år sedan. Utvecklingen har dock varierat i något olika utsträckning beroende på komponent och lokalisering i landet. Föroreningsbelastningen är oftast lägre ju längre norrut man kommer. För de flesta de ämnen som det finns miljökvalitetsnormer (MKN) respektive miljömål för ligger halterna avsevärt lägre än angivna gräns- och målvärden. Halterna av ozon överskrider i dagsläget MKN för hälsa. För såväl ozon som bensen (i urban bakgrund) och eten finns risk för haltnivåer som överstiger miljömålen.

Oil spills, the most frequent environmental incidents in Sweden, have decreased in recent years but still pose risks to drinking water and aquatic ecosystems, with about 600 cases registered annually by the Swedish Fire Protection Association. Yet, detailed information about modern fuels and their environmental and human health impacts remains scarce. Hence, this study focuses on enhancing the understanding of the environmental impact of common fuels.This study collected thirty fuel samples of different types: petrol, diesel, fuel oil, and marine gas oil. A selected number of substances in the fuels and the water-soluble phase were analysed using GC-MS.

A crucial step in the analytical method in this project, since the focus was on the effect on sub-surface aquatic life and drinking water production, was to form a stable water-accommodated fraction (WAF) where non-dissolved fuel elements were separated from the water. Since odour properties were of interest, the mixing was extensive, with limited space allowed for gases, meaning that more volatile organic carbons (VOC:s) would be in solution. The chemical analysis focused on identifying and quantifying 50 substances, including aromatic hydrocarbons, aliphatic hydrocarbons, ethers, and esters, plus 17 polycyclic aromatic hydrocarbons (PAH:s) for eight of the samples. These substances were chosen for their significance in interpreting results related to odour and to illustrate the proportion of light and heavy substances in the fuels.Twelve of the thirty fuel samples were selected for odour threshold testing, where a dilution series from the WAF was used to evaluate the intensity of odours at different concentrations. Six samples were chosen for ecotoxicological assessments on crustaceans, algae, and bacteria, offering a comprehensive understanding of the ecotoxicity of the fuel-water mixtures. Four samples were used in tailor-made evaporation experiments to study how volatile fuel components evaporate from the water surface under different temperatures and ethanol concentrations.For odour, three fuels were notably distinguished, namely the fuels containing higher concentrations of ether: 98 Octane petrol and E85 fuel.

While there was significant variability in odour thresholds among different panel members, the concentration of MTBE (Methyl Tertiary-Butyl Ether) in the fuel-water mixtures was generally identified as a precise predictor of odour. Conversely, the lack of ether in diesel fuels made them significantly less prone to cause odour in the WAF.Generally, petrol-specific substances dissolve more readily in water than those in diesel, which only marginally ended up in the water-accommodated fraction. However, ethanol in petrol and RME (rapeseed methyl ester) in diesel favoured the dissolution of hydrocarbons into water. For ether, which is of utmost importance for odour, a strong correlation was observed between the concentration of ether in water and its content in the fuel. Therefore, it is possible to predict the ether concentration in the WAF solely from ether concentration in the fuel, meaning that ethanol did not significantly increase ether solubility.In the case of a fuel spill into surface water, volatile substances like ether or toluene evaporate into the air, reducing the water concentration. The experimental conditions in this study do not reflect actual real-world conditions. The evaporation experiments showed that the evaporation of ether can be predicted based on the WAF ether concentration, water temperature, and ethanol content. It was found that cold water (5 °C) conditions reduce the evaporation rate of ether to almost negligible levels.The ecotoxicological tests showed reproduction inhibitions in crustaceans across all fuel samples. However, the inhibiting effect from HVO (hydrogenated vegetable oil) was only marginally greater than that of the control. Fuel oil and some petrol fuels had detrimental effects on the algae growth, while diesel did not.

The decrease of luminescence of bacteria, an indicator of toxicity, exhibited a similar trend; petrol fuels inhibited luminescence more than diesel. None of the fuels disturbed activated sludge to the extent that respiration was inhibited at toxic levels. This shows that an active sludge is more robust than single organisms, probably due to the diverse bacteria flora.For a drinking water producer, fuels containing water-soluble ethers, such as E85 and 98 Octane petrol, are the most prominent risk. If a spill occurs in the drinking water supply, the production disturbance likelihood depends on the dilution prerequisites below the odour threshold of 1.5-4 µg/L. The study also shows that modern diesel has become an issue of marginal concern for surface water-based raw water sources due to very low solubility and regulations that have reduced the amounts of toxic substances in the products.For freshwater ecosystems, water-soluble petrol-associated substances and hydrophobic toxic substances in fuel oil or EU diesel have the most severe effects during a spill. However, MK1 and HVO diesel only marginally affected the test organisms compared to the control, which represents unaffected organisms.

Fuel spills pose significant environmental risks, particularly to drinking water sources and aquatic ecosystems. Thecomposition of fuels has changed over the decades to reduce fossil greenhouse gas emissions. In Sweden, althoughthe number of spill incidents has declined, with around 600 cases reported annually, there remains limitedknowledge on the environmental and health impacts of modern fuels.

This study aimed to address this gap throughcomprehensive chemical analysis and ecotoxicological assessments of 31 fuel samples, including petrol, diesel, fueloil, and marine gas oil. Using gas chromatography-mass spectrometry (GC-MS), we determined 53 substances,including aromatic and aliphatic hydrocarbons, ethers, esters, and 17 polycyclic aromatic hydrocarbons (PAHs).

Akey focus was on forming a stable water-accommodated fraction (WAF) to isolate non-dissolved fuel elementsfrom water, which is crucial for assessing subsurface aquatic life and drinking water production impacts. Resultsindicated significant differences in fuel odor profiles, with ethers enhancing odor intensity. Petrol componentsshowed higher water solubility than diesel, partly due to ethanol. Ecotoxicological tests revealed varying toxicityacross fuels, with petrol showing the highest toxicity to aquatic organisms, although activated sludge exhibitedresilience.

Fuels containing water-soluble ethers posed the highest risks to drinking water, while modern diesel wasof lower concern due to its low solubility and toxicity. In freshwater ecosystems, petrol and hydrophobic toxins infuel oil had severe effects during spills. Overall, this study offers critical insights into the environmental impact of common fuels, supporting improved risk assessment and management strategies for spill mitigation and water resource protection.

The composition of vehicle fuels has changed since 2018 due to the reduction obligation, which requires that an increasing proportion of bio-based content is mixed into fossil fuels. Since properties such as odour and ecotoxicity are complex and depend on the composition of substances' mixtures, information based on older studies is not applicable. Odour properties are essential for drinking water producers, and ecotoxicity is vital for prioritising remediation efforts in the event of spillage.

The objectives of this study have therefore been to 1) quantify the composition of standard diesel and petrol fuels sold in Sweden, 2) quantify odour thresholds for these fuels in drinking water, 3) investigate the ecotoxicity from HVO (hydrogenated vegetable oil) and diesel with RME additive (rapeseed methyl ester), and 4) investigate whether it is possible to predict odour in water based on concentrations in a fuel/water mixture.In the study, a total of eight fuels were tested, of which four were diesel fuels (HVO 100, MK1 diesel with HVO, MK1 diesel with RME and MK1 diesel) and four contained petrol/ethanol to varying degrees (E85, E05, E10 with bio-petrol and E10). HVO 100 and MK1 diesel with RME were used for ecotox tests on alga, bacteria, and crustaceans, as well as for degradation tests.Petrol/ethanol fuels were more efficiently dissolved in water than diesel fuels. This is because they contain a higher proportion of more water-soluble substances, such as ethers and light aromatic compounds, and the mixture of ethanol in the fuels. The E85 fuel resulted in the highest concentrations of hydrocarbons in the water mixture, even though the proportion of petrol is only 15%. A similar effect on solubility could be observed for RME in diesel fuels, although not to the same extent.The amounts of dissolved ether determined the odour properties of fuels in water.

The 98 octane E05 fuel had the highest ether concentration in the fuel product, while the ether content of E85 was most effectively dissolved in water due to the high ethanol content. The odour thresholds were at 0.0017% in a water/fuel mixture for the E05 fuel and 0.0042% for E85. The ethers so dominated the odour that the methyl tert-butyl ether (MTBE) concentration could accurately predict the smell in an aqueous solution.Overall, the ecotoxicological tests showed mild or no effect from the fuels on the tested organisms. The exception was for the reproduction of crustaceans that were disturbed by MK1 diesel with RME. The low solubility of the two tested diesel fuels in water resulted in too low concentrations of hydrocarbons in the fuel/water mixture for valid degradation tests. 

Urbanmätnätet, som är ett samarbete mellan ett antal av Sveriges kommuner och IVL, har avslutat sitt 26:e och påbörjat sitt 27:e mätår. Urbanmätnätet bygger på samordnade, långsiktiga mätningar av luftkvaliteten i ett stort antal kommuner, utförda på ett sådant sätt att resultaten blir jämförbara mellan tätorter och år. Resultaten från kalenderår 2011 och vinterhalvår 2011/12 presenteras i denna rapport. Under år 2011 och vinterhalvåret 2011/12 deltog 28 kommuner i varierande omfattning. Totalt 14 kommuner valde att mäta hela år 2011. Mätningarna har innefattat dygnsmedelvärden av kvävedioxid (NO2), svaveldioxid (SO2), partiklar (PM10,PM2.5 och sot) samt månads-/veckoprovtagning med diffusionsprovtagare avseende NO2, SO2, ozon (O3) och lättflyktiga kolväten (VOC). Samtliga uppmätta års- och vinterhalvårsmedelvärden av NO2 underskred såväl miljökvalitetsnormen (MKN) (40 µg/m3) som övre utvärderingströskeln (ÖUT) (32 µg/m3) för årsmedelvärde. Endast i Örnsköldsviks gaturum överskreds under vinterhalvår 2011/12 fler än tillåtna antal dygn av ÖUT (48 µg/m3) för NO2 som dygnsmedelvärden. Samtliga kommuner uppvisade under år 2011 och vinterhalvår 2011/12 halter under MKN för PM10 som årsmedelvärde (40 µg/m3), i såväl urban bakgrund som gaturum. Av de deltagande kommunerna under 2011 var det tre kommuner, Örnsköldsvik, Ljungby och Sunne, där ÖUT som dygnsmedelvärde överskreds i gaturum. Knappt 60 % av tillfällena då MKN för dygnsmedelvärden (50 ?g/m3) överträddes under 2011 och vinterhalvår 2011/12 inträffade under mars och april. Mätningar av PM2.5 har endast utförts i 4 kommuner under 2011 och ytterligare 2 under vinterhalvår 2011/12.   Årsmedelvärdena låg långt under den nedre utvärderingströskeln (NUT). Halterna av bensen i gaturum såväl som i urban bakgrund under 2011 och vinterhalvåret 2011/12 låg klart under NUT. Den genomsnittliga minskningen av bensen, för de 10 kommuner som mätt mer än 15 år, har varit cirka 70 % i urban bakgrund. Den nedåtgående trenden var som störst fram till början av 2000-talet, medan halterna de senaste åren i stort sett varit oförändrade. En kommun, Köping, valde att analysera sina PM10 – filter från vinterhalvår 2010/11 avseende PAH och metaller. Timrå valde att göra metallanalys på filter från vinterhalvår 2010/11. Samtliga uppmätta halter av benso(a)pyren och metaller ligger under NUT för årsmedelvärde. Timrå valde även att utföra mätningar av 1,3-butadien samt form- och acetaldehyd diffusivt under en vecka per månad under vinterhalvår 2011/12. Mätningarna indikerar att halterna är låga och sannolikt under preciseringarna för miljökvalitetsmålet. Från de månadsvisa mätningarna av SO2 med diffusionsprovtagare framgår att samtliga vinterhalvårsmedelvärden av SO2 underskrider MKN för vinter- och årsmedelvärde (20 µg/m3) med god marginal.