IVL Swedish Environmental Research Institute

Low-cost sensors can provide inaccurate data as temperature and humidity affect sensoraccuracy. Therefore, calibration and data correction are essential to obtain reliable measurements.This article presents a training and testing method used to calibrate a sensor module assembledfrom SO2 and NO2 electrochemical sensors (Alphasense B4 and B43F) alongside air temperature (T)and humidity (RH) sensors.

Field training and testing were conducted in the industrialized coastalarea of Quintero Bay, Chile. The raw responses of the electrochemical (mV) and T-RH sensors weresubjected to multiple linear regression (MLR) using three data segments, based on either voltage(SO2 sensor) or temperature (NO2). The resulting MLR equations were used to estimate the referenceconcentration. In the field test, calibration improved the performance of the sensors after addingT and RH in a linear model.

The most robust models for NO2 were associated with data collectedat T < 10 C (R2 = 0.85), while SO2 robust models (R2 = 0.97) were associated with data segmentscontaining higher voltages. Overall, this training and testing method reduced the bias due to T andHR in the evaluated sensors and could be replicated in similar environments to correct raw data fromlow-cost electrochemical sensors. A calibration method based on training and sensor testing afterrelocation is presented. The results show that the SO2 sensor performed better when modeled fordifferent segments of voltage data, and the NO2 sensor model performed better when calibrated fordifferent temperature data segments.

The Swedish population exposure to concentrations of NO2, PM10 and PM2.5 was quantified for 2019, and the health and associated economic consequences were calculated. Most of the population was exposed to levels below the environmental standards. However, compared to the recently updated WHO 2021 Air Quality Guidelines, our calculations indicate that 82% of the population is exposed to unacceptable levels of PM2.5, and 11 % to unacceptable levels of NO2. We estimate a total of 6740 deaths per year. The health impacts can be estimated to cause socio-economic costs of ~168 billion SEK. 

Diffus damning är ett vanligt förekommande problem för verksamheter där material, såsom sten, jord, malm eller kalk, bryts, hanteras eller bearbetas. Syftet med denna studie har varit att identifiera och kvantifiera effekten av olika damningsreducerande åtgärder. Studien har fokuserat på dammande processer associerade med täktverksamhet.

För täktverksamhet identifierades fyra huvudsakliga källor till damning: losshållning, transporter, materialhantering och passiv vinddriven damning från upplag och öppna ytor. Av dessa konstaterades transporter och materialhantering (krossning och siktning) vara de källor som orsakade mest damning och valdes därav ut för test av åtgärder. Mätningar och beräkningar genomfördes för att uppskatta effekten av följande åtgärder: städning av asfaltsväg, vattenbegjutning av grusväg, vattenbegjutning vid krossning och siktning samt skumbegjutning vid krossning och siktning.

Resultaten visade att städning av asfaltsväg i stort sett inte gav någon effekt på kort sikt. Vattenbegjutning av grusväg visade sig däremot kortsiktigt vara mycket effektivt. Efter fem timmar var dock effekten av vattenbegjutningen borta. För krossning och siktning visade sig skumbegjutning vara en mycket effektiv åtgärd. Partikelemissionerna från krossen minskade med mellan 96 och 99%. Skummet tillsattes i krossen men effekten återfanns även i sikten, vars partikelemissioner minskade med 78 - 87%.

IVL and the Department of Public Health and Clinical Medicine at Umeå University have, on behalf of the Swedish EPA, performed a health impact assessment (HIA) for the year 2015. The population exposure to annual mean concentrations of NO2, PM10 and PM2.5 in ambient air has been quantified, and the health and associated economic consequences have been calculated based on these results.

To allow application of known exposure-response functions for assessment of health effects this study exclusively focus on regional and urban background concentrations. Roadside concentrations are not addressed here. The results from this study show that background concentrations of the examined pollutants in 2015 were overall low, well below the environmental standards in most parts of the country. The background concentrations were also below the environmental objective for all examined pollutants, with the exception of a small stretch along the Swedish west coast and Skåne, where the particle concentrations were of the same magnitude as the environmental objective. It should be noted that a slight over-estimation of PM2.5 may occur in coastal regions due to the presence of sea salt which may affect the PM2.5/PM10 ratio used to calculate PM2.5 in this study.

Nearly the entire Swedish population was exposed to concentrations below the environmental standards, and 97%, 78% and 77% was exposed to concentrations below the respective specifications of the environmental objective for NO2, PM10 and PM2.5. Exposure to the highest concentrations was found in the most polluted central parts of our largest cities.

Comparing the results from this study to the 2010 assessment shows a slight increase in mean population exposure to NO2 and PM. For NO2, we also find a slight increase in the percentage of the population exposed to concentrations above the environmental objective. For PM, exposure to concentrations above the environmental objective was instead found to have decreased with up to 5%. Particle concentrations show a decreasing trend in Sweden, resulting in reduced exposure to the highest PM concentrations and an increased exposure to concentrations just below the environmental objectives. The slight increase in mean population exposure to PM can be explained by a growing population and ongoing urbanization, resulting in more people exposed to relatively high PM concentrations in the urban centres. While the contribution of local sources is minor for the smallest PM, it makes up the major part of NO2 concentrations in urban areas. The slight increase indicated for NO2 exposure is thus primarily connected to increased local emissions of NO2, due to, for example, increasing traffic and use of diesel vehicles. This, in combination with the ongoing urbanization, results in a growing number of people living in areas with higher concentrations.

Excess mortality is usually the main health indicator. We estimate approximately 3600 deaths per year associated with exposure to regional background (long-distance transported) concentrations of PM2.5. On average each premature death represents over 11 years of life lost. The total exposure to PM2.5 was recently in an EU report estimated to cause just over 3700 deaths per year in Sweden when no differences between sources and no threshold for effects were assumed. We assume that locally emitted particles (road dust, wood smoke and exhaust particles) have different effects on mortality, but face problems to find specific exposure-response functions. This is even more striking regarding effects on morbidity. Acknowledging the uncertainty, we estimate particles from local wood burning to cause more than 900 deaths per year, but here the exposure estimate is very uncertain. For road dust we calculate 215 deaths per year based on the exposure-response function from a Swedish study. We believe that the impact on mortality from locally emitted vehicle exhaust including particles is best indicated by exposure-response functions for within city gradients in NO2, which also could include effects of NO2 itself. We estimate approximately 2850 deaths per year from vehicle exhaust, but using alternative risk functions would result in 15-30% reduced estimates.

The total number of excess deaths due to air pollution exposure was estimated up to 7600 in 2015. The increase in comparison to the 2010 estimate is not due to changes in estimated exposure, but resulting from a revision of assumed exposure-response relations. If we for 2010 had assumed the urban NO2 contribution to increase mortality without any cutoff, we would have estimated almost the same impact on mortality associated with NO2 as in 2015. Finally, the health impacts from exposure to NO2 and PM2.5 can be conservatively estimated to cause socio-economic costs of ~56 billion Krona in 2015. Just absence from work and studies can be estimated to cause socio-economic costs of ~0.4% of GDP in Sweden.

Denna guide riktar sig till alla verksamheter som upplever problem med diffus damning och beskriver till att börja med vad diffus damning är, vilka problem det ger samt de källor och omgivande faktorer som resulterar i damning. Den största delen av guiden är sedan ägnad åt att beskriva åtgärder som passar vid olika typer av damning.

Urban greenery is identified as a potential tool in air pollution mitigation. However, the impact is still debated. This paper introduces the innovative VIDA (Vegetation Impact Dynamic Assessment) model, specifically designed to quantify air pollution removal through deposition on vegetation. The VIDA model offers an advanced representation of vegetation that could be integrated into urban air quality dispersion models in the future. Furthermore, the model serves as a valuable tool for exploring the intricate interactions among deposition, resuspension, and wash-off processes, as well as understanding how meteorological conditions and various leaf traits influence these processes.The current version of the model focuses on particulate matter (PM) and encompasses a range of processes, including deposition on vegetation surfaces, encapsulation within the waxy cuticle, wind-driven resuspension, and wash-off.

Additionally, the model takes into consideration dynamic changes in PM concentrations on the leaf surface over time, incorporating factors such as PM size fractions, meteorological conditions, and leaf characteristics. This comprehensive approach allows for the evaluation of various species or species groups based on their distinct traits. The VIDA model effectively reproduces measured data, yet continued evaluation remains crucial as new data emerges. Notably, challenges are encountered due to data scarcity and the absence of standardized methods for characterizing vegetation traits. Addressing these challenges and refining the representation of wash-off process will enhance the VIDA model's utility in predicting the dynamic relationship between vegetation and air quality. The introduction of VIDA provides a significant advancement in modelling air pollution removal by deposition to vegetation at a relevant local scale and enables inclusion of urban greenery as tool in urban planning for air pollution mitigation. 

Integration of low-cost air quality sensors with the internet of things (IoT) has become a feasible approach towards the development of smart cities. Several studies have assessed the performance of low-cost air quality sensors by comparing their measurements with reference instruments. We examined the performance of a low-cost IoT particulate matter (PM10 and PM2.5) sensor in the urban environment of Santiago, Chile. The prototype was assembled from a PM10–PM2.5 sensor (SDS011), a temperature and relative humidity sensor (BME280) and an IoT board (ESP8266/Node MCU). Field tests were conducted at three regulatory monitoring stations during the 2018 austral winter and spring seasons. The sensors at each site were operated in parallel with continuous reference air quality monitors (BAM 1020 and TEOM 1400) and a filter-based sampler (Partisol 2000i). Variability between sensor units (n = 7) and the correlation between the sensor and reference instruments were examined. Moderate inter-unit variability was observed between sensors for PM2.5 (normalized root-mean-square error 9–24%) and PM10 (10–37%). The correlations between the 1-h average concentrations reported by the sensors and continuous monitors were higher for PM2.5 (R2 0.47–0.86) than PM10 (0.24–0.56). The correlations (R2) between the 24-h PM2.5 averages from the sensors and reference instruments were 0.63–0.87 for continuous monitoring and 0.69–0.93 for filter-based samplers. Correlation analysis revealed that sensors tended to overestimate PM concentrations in high relative humidity (RH > 75%) and underestimate when RH was below 50%. Overall, the prototype evaluated exhibited adequate performance and may be potentially suitable for monitoring daily PM2.5 averages after correcting for RH.

Increasing vegetation cover in cities is a key approach to mitigating urban heat excess. However, both the effect of vegetation on microclimate and the plants’ vitality need to be assessed to support and quantify the effects of such strategies. One way to assess the interactions between vegetation and the urban environment is through microclimate models that can simulate the effects of vegetation onto the urban microclimate as well as effects of urban environments onto vegetation. To provide reliable estimates microclimate models need to be parameterized based on empirically obtained data.

In this paper we compare modeled transpiration rates and leaf temperatures of a leading microclimate model, ENVI-met V4, with in-situ measured stem sap flow and leaf temperatures of two different trees in an urban courtyard. The vegetation model of ENVI-met is evaluated considering four synoptic situations including varying cloud covers ranging from fully cloudy to clear sky. The comparison of simulation results with empirical data reveals a high agreement. The model is capable of capturing the magnitude as well as short-term variations in transpiration caused by microclimatic changes. However, substantial deviations were found in situations with low photosynthetic active radiation. Modeled and observed diurnal tree transpiration and leaf temperature showed good agreement. These findings indicate that ENVI-met is capable of simulating transpiration rates and leaf temperatures of trees in complex urban environments.

The village Haparanda in northern Sweden hosts one of the longest meteorological station records in Europe depicting climate conditions in the subarctic. Since the station was relocated several times, moving gradually from urbanized to more rural areas, the record is likely biased by anthropogenic influences. We here assess these influences and demonstrate that even in villages urban heat island biases might affect the temperature readings. We detail a method to quantify this bias and remove it from the long Haparanda station record running since 1859.

The correction is based on parallel temperature measurements at previous station locations in Haparanda. These measurements revealed a distinct urban warming pattern, largest in minimum temperatures during summer, since urban geometry and its heat capacity amplify additional warming and night-time heat release, especially during a period of high insolation and calm conditions. Due to the station movement from the village centre to the outskirts, the net correction results in an additional warming trend over the past 155 years.

The trend increase is most substantial for minimum temperatures (+0.03 ∘C10years−1). Maximum and mean temperatures are less affected (+0.01 ∘C10years−1). An increase in trend is even more severe if the 20th century is regarded exclusively, displaying a rise in annual mean temperature trend by +0.03 ∘C10 years−1 and +0.07 ∘C 10 years−1 in annual minimum temperatures, respectively.Our approach of using actual temperature differences between historical station locations did not take into account other factors that might have influenced the data such as changes in instruments or observers.

The presented adjustment for temperature residuals caused by a change in historical station locations might be considered as a minimum approach to improve long-term temperature readings. The adjustment of the Haparanda station record results in an increased warming trend, thereby adding critical information to the evaluation and explanation of 20th century anthropogenic warming.

tGlobal warming is likely to increase the frequency and magnitude of heat waves. As the urban geometryand material amplifies warming, city dwellers will face an intensification of heat-induced health prob-lems and mortality. Although increased vegetation cover is frequently used in urban planning to mitigateexcessive heat, temporal variations, as well as the influence of synoptic weather conditions and surround-ing urban geometry on the vegetation cooling effect, are still unclear. In this study, we monitored thetranspiration-induced cooling from trees over two summers in five urban settings characterized by vary-ing levels of greenness and urban geometry in the city of Mainz (Germany).

Differences in air temperatureand humidity patterns were compared with estimates of tree transpiration derived from high-resolutionstem size and sap flow measurements. Results from the five urban sites indicate significant cooling dueto transpiration, but with large variability depending on time of day and weather conditions.

The coolingeffect is strongest during periods of high transpiration demand, and in the stable nocturnal boundarylayer when air mixing is limited. The strongest transpiration cooling was found in an enclosed courtyardstructure. These findings reveal that a few trees can substantially mitigate urban excess heat, but that theurban geometry, time of the day, and prevailing weather conditions considerably modulate this effect.

Although urban heat islands (UHIs) have been found in many cities throughout the world, work on smaller settlements is still limited, especially concerning variations connected to climate zones. Meteorological stations are often regarded as rural when located in a village or small town, and any temperature bias is assumed negligible. In this paper, we therefore present air temperature variations and their connection to land cover in 3 European villages, boreal Haparanda, temperate Geisenheim, and Mediterranean Cazorla, all of them hosting long temperature records that might be biased. The villages were equipped with temperature sensors, and the surrounding areas were digitized to compare UHI effects and to evaluate the contribution of land cover on local cooling and warming. This sensor network reveals significant village UHIs in all 3 climate zones, with seasonal maximum intensities decreasing from north (1.4°C) to south (0.9°C). During summer, urban warming is most emphasized in minimum temperatures in boreal Haparanda and temperate Geisenheim but weakest in Mediterranean Cazorla, presumably because of limited plant transpiration due to high insolation and drought stress. Urban warming is correlated with building density in all 3 settlements and shows little seasonal variation. Even though the mountain river passing Cazorla substantially cools ambient temperatures at distances <100 m, mitigation of warming through water bodies is limited in the Central and Northern European sites. Our results suggest to treat rural instrumental station data with care and to avoid using data recorded in villages as unbiased reference records to adjust measurements from larger cities.

Intervjuer med kommuner och länsstyrelser har genomförts för att kartlägga hur luftkvalitetsaspekten hanteras i stadsutvecklingsprocessen. Studien visar att ett stort engagemang och intresse finns för frågan. Dock finns förbättringspotential, och ett antal förslag på hur arbetet med luftkvalitet kan gynnas i framtida stadsutveckling har identifierats.

Urban vegetation has the potential to improve air quality as it promotes pollutant deposition and retention.Urban air quality models often include the effect vegetation have on pollution dispersion, however, processesinvolved in pollution removal by vegetation are often excluded or simplified and does not consider differentvegetation characteristics. In this systematic review, we analyze the influence of the large interspecies variationin vegetation characteristics to identify the key factors affecting the removal of the major urban pollutants,particulate matter (PM) and nitrogen dioxide (NO2) from the air through vegetation deposition.

The aim is toidentify key processes needed to represent vegetation characteristics in urban air quality modelling assessments.We show that PM is mainly deposited to the leaf surface, and thus representation of characteristics affectingthe aerodynamics from canopy down to leaf surface are important, such as branch/shoot complexity and leafsize, leaf surface roughness and hairiness. In addition, characteristics affecting PM retention capacity, resuspensionand wash-off, include leaf surface roughness, hairiness and wax content. NO2 is mainly depositedthrough stomatal uptake, and thus stomatal conductance and its responses to environmental conditions are keyfactors. These include response to solar radiation, vapour pressure deficit and soil moisture.Representation of these vegetation characteristics in urban air quality models could greatly improve ourability to optimize the type and species of urban vegetation from an air quality perspective.

Den starka förtätningstrenden i svenska städer motiveras av möjligheter till ökad energieffektivisering, minskade utsläpp av växthusgaser, mer samtransport och ökad kollektiv resursfördelning. Förtätning kan också medföra kraftigt försämrad luftkvalitet, till exempel om den ökade aktivitet som förtätningen innebär tillåts öka utsläpp av luftföroreningar, och om bebyggelse och vegetation placeras så att det hindrar ventilation och utspädning av luftföroreningarna. Genom noggrann stadsplanering kan dock dessa negativa effekter begränsas eller till och med undvikas helt. Det är därmed av största vikt att skapa både medvetenhet om vikten av och möjligheter till att inkludera luftkvalitetsaspekten i planering av framtidens hållbara och täta städer.

Trots en kraftig förtätning under senare år har luftkvaliteten generellt förbättrats från det att mätningar påbörjades för drygt 50 år sedan och fram till idag, vilket i huvudsak kopplas till minskade utsläpp av föroreningar till följd av kontinuerligt skärpta emissionskrav. I många av Sveriges städer överskrids dock fortfarande de tillåtna halterna av föroreningar, och prognoser indikerar att miljökvalitetsmålets preciseringar, och i vissa fall även miljökvalitetsnormerna, fortfarande kommer att överskridas i gatumiljö i större städer år 2030. I detta framtidsscenario beaktas inte eventuell förtätning. Nyligen sänkta bullerkrav skapar dessutom idag ökade möjligheter att bygga på redan förorenade platser, vilket, i kombination med en fortsatt kraftig förtätning, ger starka argument för att luftkvalitet bör hanteras som en viktig del i framtidens hållbara stadsutveckling.

För att förhindra dålig luftkvalitet i förtätade städer kan man i planeringsstadiet använda datormodeller för att utvärdera effekten av de planerade förändringarna på luftkvaliteten. Genom simulering av olika scenarier kan effekten av olika trafikåtgärder på utsläpp, och därmed luftkvalitet, undersökas. Med modellberäkningar kan också effekten av olika utformning av bebyggelse och vegetation på vindflödet genom det aktuella området utvärderas för att gynna utspädning och borttransport av förorenad luft. Här kan till exempel varierad höjd på byggnader, vinkel på huskropp mot huvudsaklig vindriktning, strategisk placering av huskropp eller vegetation som barriär mellan utsläppskälla och platser där människor vistas, vara gynnsamt. För att ge bästa möjliga luftkvalitet efter färdigställande krävs dock att luftutredningen genomförs med relevanta metoder, att den inkluderas tidigt i planeringsprocessen, att anpassning av planer utifrån resultaten tillåts, samt att kontinuerlig återkoppling sker.

Arbetet med luftkvalitet skulle gynnas av bland annat tydligare riktlinjer för när och hur luftkvalitetsaspekten bör inkluderas i planeringsarbete, hur effekterna av den planerade bebyggelsen ska utvärderas, samt hur man kan säkerställa att planerade åtgärder genomförs så att den förväntade effekten på luftkvaliteten i området uppfylls. Vidare skulle till exempel en framtida skärpning av miljözon 2 och 3, utökade möjligheter för gröna transportplaner och vägledning om flexibla parkeringstal underlätta för sänkta emissioner i framtidens täta städer.

Sammantaget finns goda grunder för att inkludera luftkvalitet i planeringsprocessen för att nå en hållbar stadsutveckling, speciellt i områden som ska förtätas. Genom optimerad utformning av bebyggelse och vegetation, tillsammans med effektiva trafikåtgärder för att minska utsläpp, kan risken för dålig luft i framtidens täta och gröna städer minimeras.

Förtätning av städer innebär många miljöfördelar i form av effektivare användning av infrastruktur och service och minskade transporter, men det finns även en risk att tätare bebyggelse försämrar luften i städerna om förtätningen medför att luftgenomströmningen minskar. Med hjälp av datormodeller har effekten på luftkvalitet från olika scenarier simulerats i denna studie, med syfte att tydliggöra hur utformningen av framtidens täta, gröna städer kan optimeras med avseende på luftkvalitet.

Samordnad varudistribution i kommunal regi har testats i flera kommuner i Sverige, och trots att intresset för konceptet växer i landet finns det brist på grundliga utvärderingar om hur den här typen av logistikförändringar påverkar miljön. I rapporten presenteras en utvärdering av miljöeffekter och samhällsekonomi av projektet Samordnad varudistribution på Södertörn. Utvärderingen har genomförts av IVL Svenska Miljöinstitutet på uppdrag av Länsstyrelsen i Stockholms län och med finansiering av Energimyndigheten. Samordningsprojektet startade 2014 och innefattar åtta kommuner med ett gemensamt invånarantal på cirka 500 000.

Mellan åren 2014 och 2017 har de fossila koldioxidutsläppen relaterat till distribution av varor (kommunalt och privat gods) i kommunerna minskat med 73 procent, vilket främst beror på en ökning av användningen av biobaserade drivmedel. Motsvarande körsträcka har minskat med fyra procent. Hur koldioxidutsläppen och körsträckan förknippat med enbart det kommunala godset har påverkats av samordnad varudistribution har inte kunnat särskiljas från den totala effekten men antalet leveranstillfällen till de kommunala enheterna har halverats jämfört med innan samordningsprojektet infördes, baserat på data från tre kommuner. Förstudien som genomfördes innan projektet startade visade på större effekter gällande minskade körsträckor. En anledning till att resultaten skiljer sig är att man i förstudien inte tog hänsyn till att de stora fullsortimentsleverantörerna till en hög grad samordnade sina varutransporter redan innan samordningsprojektet genomfördes.

Utsläppen av kväveoxider och partiklar inom kommungränserna har även dessa minskat med omkring 70 procent. Effekten på den lokala luftkvalitén är dock försumbar eftersom minskningarna i emissioner från varudistributionen trots allt är små jämfört med utsläppen från övrig trafik. De minskade utsläppen av luftföroreningar från varudistributionen i kommunerna beror främst på en ökad användning av Euro VI-lastbilar.

Vid tillfället för utvärderingen har samordnad varudistribution implementerats i samtliga åtta kommuner men det kvarstår att ansluta fler varugrupper och leverantörer och att omförhandla flertalet leverantörsavtal. En uppföljande utvärdering bör därför utföras om ytterligare några år för att avgöra den fulla effekten av samordnad varudistribution. Denna studie visar potentialen för samordnad varudistribution för några alternativa scenarion. I nuläget har samordningsprojektet inte lett till fler lokala leverantörer men möjligheterna för lokala leverantörer att ansluta sig vid kommande upphandlingar har förbättrats. Vid en övergång till en ökad andel lokala leverantörer visar utvärderingen att den samordnade varudistributionen har potential att minska miljöpåverkan. Kommunalt samordnade varutransporter, med tydliga krav på användning av icke-fossila bränslen, kan också visa sig vara en viktig åtgärd för att kunna säkra dagens med biodrivmedel uppnådda klimatvinster.

De samhällsekonomiska vinsterna med samordningsprojektet är i dagsläget små jämfört med de ökade projektkostnaderna som det medfört. Det kontrakterade åkeriets distributionstrafik dominerar kostnaderna, men även kommunernas administrativa kostnader som kan knytas till samordningsprojektet är betydande. Dessa kostnader kan delvis knytas till den introduktionsfas som fortfarande pågår, varför dessa förväntas minska då projektet hösten 2017 övergår till en förvaltnings- och utvecklingsfas. Av de miljönyttor som har kvantifierats står minskad klimatpåverkan för den största. En betydande framtida kostnadsbesparing för kommunerna ligger i lägre varukostnader, då sluttransporten för varan i framtiden inte bör ingå i priset för varorna. Effekten på arbetsmiljön har inte kunnat fastställas baserat på de intervjuer som har utförts, men det är tydligt att upplevelsen hos de anställda inom kommunernas verksamheter skiljer sig mellan olika kommuner. Liksom i andra studier av samordnad varudistribution har kommunikation identifierats som en nyckel till ett fungerande system, såväl internt inom kommunerna som mellan åkeriet som är kontrakterat för distributionstrafiken och varuleverantörerna.

A newly developed remote sensing instrument with NO2 and NOX measurement capability was operated in the fall of 2016 over 19 workdays in Gothenburg, Sweden, to measure real driving emissions from a large number light- and heavy-duty vehicles. From more than 30,000 registered vehicle passages, a final QA/QC-reviewed dataset consisting of about 15,000 paired records containing emissions, driving condition and detailed vehicle information data, was used to evaluate the real-world emission performance of in particular Euro 5 and Euro 6 diesel vehicles. More than 9,000 records were of diesel vehicles, of which about 5,500 were of Euro 5 vehicles and about 2,600 of Euro 6 vehicles. The following conclusions were made from the evaluation:

- Measurements on more than 6,000 diesel passenger cars reveal that the real driving emissions of NOX from Euro 6 diesel cars on average have been reduced by about 60% from pre-Euro 6 levels, e.g. Euro 5. This may be considered a major breakthrough, since the real-world NOX emissions from diesel passenger cars have been virtually unchanged between Euro 2 and Euro 5, although the NOX emission standard has been significantly lowered from Euro 2 to Euro 5. Still, Euro 6 diesel passenger car real-world NOX emissions are roughly more than 5 times higher than the Euro 6 standard, as well as than the measured average on-road NOX emissions from Euro 6 gasoline passenger cars.

- For NOX emissions, an almost identical pattern as for diesel passenger cars was observed for both diesel light-duty commercial vehicles and diesel heavy-duty vehicles (trucks and buses), i.e. virtually no change in real-world emissions between Euro 2 and Euro 5, followed by a major drop in emissions for Euro 6.

- Primary NO2 emissions from diesel light-duty vehicles (both PC and LCV) have been reduced from Euro 4 through Euro 6, implying that the emission ratio of NO2 to NOX has also been reduced, but the ratio is still as high as about 25% for both Euro 5 and Euro 6 (compared to about 15% for Euro 2). The opposite pattern exists for heavy-duty vehicles, for which the NO2/NOX-ratio increased from about 10% for Euro 4-5 to ≈35% for Euro 6.

- For all categories of diesel vehicles, real-world PM emissions have dropped steadily from Euro 2 through Euro 6 – reductions are in the order of 90% for Euro 6 compared to Euro 2.

- For Euro 4, 5 and 6 diesel passenger cars, real-world emissions of both NOX and NO2 increase with decreasing ambient air temperature. The temperature dependence appears to be strongest for Euro 5 cars. At 25-30 degrees C average Euro 5 NOX on-road emissions are around 15 g/kg fuel burned, rising to 20-25 g/kg fuel burned at around 10 degrees C.

- Large differences in the on-road NOX emission performance were observed between different makes, models, as well as individual vehicles among Euro 5 and Euro 6 diesel passenger cars.

- For the first time, remote sensing measurements were combined with air quality measurements and dispersion calculations in an urban street canyon. Calculated average concentrations of NO2, NOX and PM based on HBEFA 3.2 were comparable with corresponding measured concentrations, but the discrepancy increased with increasing concentrations, with calculated concentrations being lower than measured. The latest version of the HBEFA emission model (version 3.3), launched in May 2017, provided a good match with the remote sensing measurements for both NOX and NO2 as well as exhaust PM, but at the same time tended to lead to an overestimation of street canyon concentrations of NO2 and NOX in dispersion calculations carried out in this study.

Using low-cost air quality sensors (LCS) in citizen science projects opens many possibilities.LCS can provide an opportunity for the citizens to collect and contributewith their own air qualitydata. However, low data quality is often an issue when using LCS and with it a risk of unrealisticexpectations of a higher degree of empowerment than what is possible. If the data quality andintended use of the data is not harmonized, conclusionsmay be drawn on the wrong basis anddata can be rendered unusable.

Ensuring high data quality is demanding in terms of labor andresources. The expertise, sensor performance assessment, post-processing, as well as thegeneral workload required will depend strongly on the purpose and intended use of the airquality data. It is therefore a balancing act to ensure that the data quality is high enough for thespecific purpose, while minimizing the validation effort. The aim of this perspective paper is toincrease awareness of data quality issues and provide strategies to minimizing labor intensityand expenses while maintaining adequate QA/QC for robust applications of LCS in citizenscience projects.

We believe that air quality measurements performed by citizens can be betterutilized with increased awareness about data quality and measurement requirements, incombination with improved metadata collection. Well-documented metadata can not onlyincrease the value and usefulness for the actors collecting the data, but it also the foundation forassessment of potential integration of the data collected by citizens in a broader perspective.

Transportstyrelsen har anlitat IVL Svenska Miljöinstitutet AB (IVL) för att undersöka effekter av utökade miljözonskrav i centrala Stockholm som även skulle omfatta personbilar. Utredningen analyserar hur användandet av miljözoner för personbilar kan utvecklas för att bättre bidra till uppfyllelsen av miljökvalitetsnormer och miljökvalitetsmål för luft.

Uppdraget har sin bakgrund i ett nu aktuellt regeringsuppdrag som handlar om att ge aktualiserat underlag och ta fram förslag om miljözoner för deras vidare arbete med tänkbara framtida styrmedel inom transportsektorn. Utredningen omfattar fem olika framtida scenarier som benämns S1, S3, S4, S5 och S6 under åren 2020, 2025 och 2030. Beräkningar av vägtrafikens emissioner har gjorts för emissioner för alla år och scenarier, dessutom har modellberäkningar gjorts dels över hela nuvarande miljözonen, dels i tre kritiska gaturum där hänsyn tagits till specifika lokala förutsättningar. För modellberäkningarna har enbart några få kombinationer av scenarier och år valts ut, eftersom många kombinationer ger samma eller nästan samma resultat. Scenarierna är följande:

Scenario 1 (S1). Redan beslutade miljözonskrav (tunga fordon) Scenario 3 (S3). Redan beslutade miljözonskrav (tunga fordon) + lätta fordon måste ha Euro 5- motor eller bättre, för lätta dieselfordon krävs dessutom Euro 6. Scenario 4 (S4). Redan beslutade miljözonskrav (tunga fordon) + lätta fordon utan undantag måste ha Euro 6c- motor (med RDE-krav). Scenario 5 (S5). Scenario 1 + avgasfritt Gamla Stan Scenario 6 (S6). Scenario 1 + avgasfritt och dubbdäcksförbud i Gamla Stan

This report is only available in Swedish.