Browsing by Subject "hiukkaset"

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  • Seppänen, Vanamo (Helsingfors universitet, 2010)
    Tässä tutkimuksessa tarkasteltiin viljelykäytössä olevan happaman sulfaattimaan Ap- ja Bg1- horisonttien aggregaattien stabiilisuudessa tapahtuvia muutoksia neljän viikon tulvituksen aikana. Tulvitus estää maan kaasunvaihdon, mikä aiheuttaa hapen puutetta maaperässä. Tästä seuraa muutoksia maan kemiallisissa olosuhteissa, muun muassa maan rakennetta stabiloivan raudan liukoisuus lisääntyy. Tutkimus suoritettiin laboratoriokokeena. Aggregaattien stabiilisuuden mittarina käytettiin märkäseulonnassa irtoavien alle 250 ?m:n kokoisten hiukkasten sekä kolloidiaineksen (< 2 ?m) määrää. Märkäseulonnassa irtoavan maa-aineksen määrää selvitettiin gravimetrisillä mittauksilla sekä laservaloon perustuvilla menetelmillä. Työssä käytetyt laservaloon perustuvat menetelmät olivat dynaaminen valonsironta sekä partikkelilaskenta. Dynaamista valonsirontaa käytettiin kolloidiaineksen määrän mittaamiseen. Menetelmän ongelmana oli tulosten välinen suuri hajonta. Alle 250 ?m:n kokoisten hiukkasten määrää mitattiin partikkelilaskurilla. Tätä mittausta vaikeutti laitteen vaatima pieni partikkelikonsentraatio sekä suurimpien partikkelien jääminen mittauksen ulkopuolelle. Aggregaattien stabiilisuuden tarkastelussa käytettiin gravimetristen mittausten tuloksia. Tulosten perusteella Bg1-horisontin murut olivat huomattavasti Ap-horisontin muruja kestävämpiä. Tähän saattoi olla syynä raudan suurempi määrä Bg1-horisontissa. Ap-horisontin näytteissä sekä makro- että mikroaggregaattien stabiilisuus väheni kokeen aikana. Myös Bg1- horisontin näytteissä mikroaggregaattien kestävyys heikkeni, mutta ei yhtä paljon kuin Aphorisontin näytteissä. Ap-horisontin makroaggregaattien stabiilisuuden heikkenemiseen saattoi olla syynä niitä koossa pitävien juurten mikrobiologinen hajoaminen. Bg1-horisontin mikroaggregaattien hajoaminen oli mahdollisesti seurausta raudan liukenemisesta. Aggregaattien stabiloituminen kokeen loppua kohti aiheutui luultavasti johtokyvyn noususta näytteissä. Syyt stabiilisuusmuutoksiin kaipaavat kuitenkin vielä jatkotutkimuksia.
  • Vepsäläinen, Sampo; Calderón, Silvia M.; Malila, Jussi; Prisle, Nønne L. (Copernicus Publ., 2022)
    Atmospheric chemistry and physics
    Surface active compounds (surfactants) are frequently found in atmospheric aerosols and droplets. As they adsorb to the surfaces of microscopic systems, surfactants can decrease aqueous surface tension and simultaneously deplete the bulk concentration. These processes may influence the activation of aerosols into cloud droplets and investigation of their role in cloud microphysics has been ongoing for decades. In this work, we have used six different models documented in the literature to represent surface activity in Köhler calculations of cloud droplet activation for particles consisting of one of three moderately surface active organics (malonic, succinic or glutaric acid) mixed with ammonium sulfate in varying mass ratios. For each of these organic acids, we find that the models predict comparable activation properties at small organic mass fractions in the dry particles, despite large differences in the predicted degree of bulk-to-surface partitioning. However, differences between the model predictions for the same dry particles regarding both the critical droplet diameters and supersaturations increase with the organic fraction in the particles. Comparison with available experimental data shows that models assuming complete bulk-to-surface partitioning of the moderately surface active component (total depletion of the bulk) do not adequately represent the droplet activation of particles with high organic mass fractions. When reduced droplet surface tension is also considered, these predictions somewhat improve. Models that consider partial bulk-to-surface partitioning of surface active components yield results comparable to experimental supersaturation data, even at high organic mass fractions in the particles, but predictions of the degree of organic bulk–surface partitioning strongly differ. This work highlights the need to use a thermodynamically consistent model framework to treat the surface activity of atmospheric aerosols and for firm experimental validation of model predictions across a wide range of droplet states relevant to the atmosphere.
  • Harni, Sami D.; Saarikoski, Sanna; Kuula, Joel; Helin, Aku; Aurela, Minna; Niemi, Jarkko V.; Kousa, Anu; Rönkkö, Topi; Timonen, Hilkka (Pergamon., 2023)
    Atmospheric environment
    Particle size distribution is a major factor in the health and climate effects of ambient aerosols, and it shows a large variation depending on the prevailing atmospheric emission sources. In this work, the particle number size distributions of ambient air were investigated at a suburban detached housing area in northern Helsinki, Finland, during a half-year period from winter to summer of 2020. The measurements were conducted with a scanning mobility particle sizer (SMPS) with a particle size range of 16–698 nm (mobility diameter), and the events with a dominant particle source were identified systematically from the data based on the time of the day and different particle physical and chemical properties. During the measurement period, four different types of events with a dominant contribution from either wood-burning (WB), traffic (TRA), secondary biogenic (BIO), or long-range transported (LRT) aerosol were observed. The particle size was the largest for the LRT events followed by BIO, WB, and TRA events with the geometric mean diameters of 72, 62, 57, and 41 nm, respectively. BIO and LRT produced the largest particle mode sizes followed by WB, and TRA with the modes of 69, 69, 46, and 25 nm, respectively. Each event type had also a noticeably different shape of the average number size distribution (NSD). In addition to the evaluation of NSDs representing different particle sources, also the effects of COVID-19 lockdown on specific aerosol properties were studied as during the measurement period the COVID-19 restrictions took place greatly reducing the traffic volumes in the Helsinki area in the spring of 2020. These restrictions had a significant contribution to reducing the concentrations of NOx and black carbon originating from fossil fuel combustion concentration, but insignificant effects on other studied variables such as number concentration and size distribution or particle mass concentrations (PM1, PM2.5, or PM10).
  • Karvosenoja, Niko (Finnish Environment Institute, 2008)
    Monographs of the Boreal Environment Research 32
    Air pollution emissions are produced in a wide variety of sources. They often result in detrimental impacts on both environments and human populations. To assess the emissions and impacts of air pollution, mathematical models have been developed. This study presents results from the application of an air pollution emission model, the Finnish Regional Emission Scenario (FRES) model, that covers the emissions of sulfur dioxide (SO2), nitrogen oxides (NOx), ammonia (NH3), non-methane volatile organic compounds (NMVOCs) and primary particulate matter (TSP, PM10, PM2.5 and PM1) in high 1 ´ 1 km2 spatial resolution over the area of Finland. The aims of the study were to identify key emission sources in Finland at present and in the future, to assess the effects of climate policies on air pollution, and to estimate emission reduction potentials and costs. Uncertainties in emission estimates were analyzed. Finally, emission model characteristics for use in different air pollution impact applications were discussed.The main emission sources in Finland are large industrial and energy production plants for SO2 (64% of 76 Gg a-1 total in the year 2000). Traffic vehicles are the main contributors for NOx (58% of 206 Gg a-1), NMVOCs (54% of 152 Gg a-1) and primary PM2.5 (26% of 31 Gg a-1) emissions. Agriculture is the key source for NH3 (97% of 33 Gg a-1). Other important sources are domestic wood combustion for primary PM2.5 (25%) and NMVOCs (12%), and fugitive dust emissions from traffic and other activities for primary PM10 (30% of 46 Gg a-1).In the future, the emissions of traffic vehicle exhaust will decrease considerably, by 76% (NMVOCs), 74% (primary PM2.5) and 60% (NOx), from 2000 to 2020, because of tightening emission legislations. Rather smaller decrease is anticipated in the emissions of large combustion plants, depending on future primary energy choices. Sources that are not subject to tight emission standards, e.g. domestic combustion and traffic-induced fugitive dust (i.e. non-exhaust), pose a risk for increasing emissions.The majority of measures to abate climate change, e.g. energy saving and non-combustion based energy production, lead to co-benefits as reduced air pollution emissions, especially of SO2 (20% to 28% reduction). However, promotion of domestic wood combustion poses a risk for increase in PM2.5 and NMVOCs emissions. Further emission reductions with feasible control costs are possible mainly for PM2.5 in small energy production plants and domestic combustion sources. Highest emission uncertainties were estimated for primary PM emission factors of domestic wood combustion, traffic non-exhaust sources and small energy production plants.The most important characteristics of emission models are correct location information of flue gas stacks of large plants for the assessment of acidification, and description of small polluters with high spatial resolution when assessing impacts on populations. Especially primary PM2.5 emissions originate to a considerable degree from small low-altitude sources in urban areas, and therefore it is important to be able to assess the impacts that take place near the emission sources. Detailed descriptions of large plants and 1 ´ 1 km2 spatial resolution for small emission sources applied in the FRES model enable its use in the assessment of various national environmental impacts and their reduction possibilities.The main contribution of this work was the development of a unique modeling framework to assess emission scenarios of multiple air pollutants in high sectoral and spatial resolution in Finland. The developed FRES model provides support for Finnish air pollution polices and a tool to assess the co-benefits and trade-offs of climate change strategies on air pollution.
  • Tohka, Antti; Karvosenoja, Niko (Finnish Environment Institute, 2006)
    Reports of the Finnish Environment Institute 21/2006
  • Savolahti, Mikko; Karvosenoja, Niko; Kupiainen, Kaarle; Paunu, Ville-Veikko; Sippola, Olli; Jokiniemi, Jorma (Suomen ympäristökeskus, 2009)
    Suomen ympäristökeskuksen raportteja 30/2009
  • Antila, Marko; Mattila, Inga; Isomoisio, Heikki; Kataja, Jari; Salmela, Hannu; Koskinen, Heli; Alanko, Tommi (Teknologian tutkimuskeskus VTT Oy, 2018)
  • Rautio, Mikko (Etelä-Savon ympäristökeskus, 2007)
    ESAra 1/2007
    Julkaisu sisältää tietoa Etelä-Savon ympäristökeskuksen toiminta-alueella (Etelä-Savon maakunta) aiheutuvasta ympäristökuormituksesta. Tiedot on koottu Ympäristöhallinnon ylläpitämästä Valvonta- ja kuormitustietojärjestelmästä (VAHTI), jonne ympäristölupavelvolliset vuosittain ilmoittavat tiedot mm. ilma- ja vesipäästöistä sekä jätemääristä. Raportti keskittyy vuoden 2005 tietoihin, mutta osa tiedoista on aikaisemmilta vuosilta, jos vuoden 2005 tietoja ei ole ollut saatavilla. Raporttiin on koottu tietoa myös aikaisempien vuosien kuormituksesta, jotta voidaan seurata kuormituksen kehittymistä. Ihmisen aiheuttama ympäristökuormitus Etelä-Savossa on erittäin vähäistä verrattuna muuhun Suomeen. Etelä- Savosta puuttuu lähes kokonaan suuret teollisuuslaitokset, jotka ovat suuria piste-kuormittajia. Maakunnan asukasmäärä ja –tiheys ovat pieniä verrattuna keskimäärin muuhun Suomeen, jolloin yhdyskuntien pistekuormittajat (esim. voimalaitokset ja jätevedenpuhdistamot) ovat kooltaan melko pieniä ja kuormitus vähäistä.
  • Kukkonen, Jaakko; Karppinen, Ari; Sofiev, Mikhail; Kangas, Leena; Karvosenoja, Niko; Johansson, Matti; Tuomisto, Jouni; Aarnio, Päivi; Kousa, Anu; Pirjola, Liisa; Kupiainen, Kaarle (2008)
    Tutkimuksia - Undersökningar - Studies
  • Makkonen, Ulla; Saarnio, Karri; Ruoho-Airola, Tuija; Hakola, Hannele (Ilmatieteen laitos, 2016)
    Raportteja - Rapporter - Reports 2016:2
    Eutrophication caused by nitrogen and phosphorus load is generally thought as the most severe problem of the Baltic Sea. Nitrogen and phosphorus end up in the Baltic Sea not only by run-off from the coastal countries of the Baltic Sea but to an important extent also from the atmosphere. The amount of atmospheric nitrogen load and its development have been determined using measurements and models since the 1980’s. The atmospheric phosphorus load to the Baltic Sea has been measured earlier only from the wet deposition from the collected rain water samples from a few sites around the Baltic Sea; no published data exists about the particle bound dry deposition of phosphorus. The coastal countries of the Baltic Sea haven’t got any method in use to measure the particle bound phosphorus deposition. In this work, methods for determining the concentrations of phosphate and total phosphorus in atmospheric precipitation and particulate matter were developed and tested. The method development included the sampling, sample pre-treatment, and chemical analysis techniques. The methods were tested onsite on the Utö Island in the outskirts of the Archipelago Sea during the years 2013–2015. The monitoring station on the Utö Island is operated by the Finnish Meteorological Institute. The measurements on the station represent the background air quality of the northern Baltic Sea area. The existing and widely used sampling methods based on the EMEP protocols were tested for the sampling of dry and wet deposition of phosphorus and phosphate. A spectrometric method based on an ISO standard was applied for determination of the total phosphorus concentration of the samples. For the determination of dissolved phosphate, an ion chromatographic method based on an ISO standard was extended to include the analysis of phosphate with the main inorganic ions. It was discovered that the concentrations of total phosphorus and dissolved phosphate in the dry and wet deposition samples were very low; the concentrations were often close to the determination limits of the used analytical methods or even below those. Nevertheless, a sufficiency of samples were determined to be able to estimate the yearly atmospheric phosphorus load to the Baltic Sea more reliably than earlier. In addition, feasibility of measuring the concentration of particle-bound phosphate using a semi-continuous ion chromatograph was tested in the Utö Island during an intensive campaign. However, the sensitivity of the analyser was not sufficient to measure the low atmospheric concentrations of phosphate. The used methods are presented in this report so that they can be taken into use in other sampling sites and laboratories to determine the concentrations of phosphate and total phosphorus in the precipitation and in the atmospheric particulate matter. Thus, more reliable estimates of the atmospheric phosphorus load to the Baltic Sea could be calculated more widely.
  • Dolar, Andraž; Selonen, Salla; van Gestel, Cornelis A.M.; Perc, Valentina; Drobne, Damjana; Jemec Kokalj, Anita (Elsevier, 2021)
    Science of The Total Environment 772 (2021), 144900
    Microplastics and agrochemicals are common pollutants in terrestrial ecosystems. Their interaction during coexistence in soils may influence their fate and adverse effects on terrestrial organisms. The aim of this study was to investigate how the exposure to two types of microplastics; polyester fibres, and crumb rubber; induce changes in immune parameters of Porcellio scaber and if the co-exposure of microplastics affects the response induced by the organophosphate pesticide chlorpyrifos. A number of immune parameters, such as total haemocyte count, differential haemocyte count, and phenoloxidase-like activity were assessed. In addition, the acetylcholinesterase (AChE) activity in the haemolymph was evaluated as a measure of the bioavailability of chlorpyrifos. After three weeks of exposure, the most noticeable changes in the measured immune parameters and also a significantly reduced AChE activity were seen in chlorpyrifos-exposed animals. Both types of microplastic at environmentally relevant concentrations caused only slight changes in immune parameters which were not dependent on the type of microplastic, although the two types differed significantly in terms of the chemical complexity of the additives. Mixtures of chlorpyrifos and microplastics induced changes that differed from individual exposures. For example, alterations in some measured parameters suggested a reduced bioavailability of chlorpyrifos (AChE activity, haemocyte viability) caused by both types of microplastics exposure, but the increase of haemocyte count was promoted by the presence of fibres implying their joint action. In conclusion, this study suggests that immune processes in P. scaber are slightly changed upon exposure to both types of microplastics and microplastics can significantly modulate the effects of other co-exposed chemicals. Further research is needed on the short-term and long-term joint effects of microplastics and agrochemicals on the immunity of soil invertebrates.
  • Savolahti, Mikko; Lehtomäki, Heli; Karvosenoja, Niko; Paunu, Ville-Veikko; Korhonen, Antti; Kukkonen, Jaakko; Kupiainen, Kaarle; Kangas, Leena; Karppinen, Ari; Hänninen, Otto (MDPI, 2019)
    International Journal of Environmental Research and Public Health
    Exposure to fine particles in ambient air has been estimated to be one of the leading environmental health risks in Finland. Residential wood combustion is the largest domestic source of fine particles, and there is increasing political interest in finding feasible measures to reduce those emissions. In this paper, we present the PM2.5 emissions from residential wood combustion in Finland, as well as the resulting concentrations. We used population-weighed concentrations in a 250 × 250 m grid as population exposure estimates, with which we calculated the disease burden of the emissions. Compared to a projected baseline scenario, we studied the effect of chosen reduction measures in several abatement scenarios. In 2015, the resulting annual average concentrations were between 0.5 and 2 µg/m3 in the proximity of most cities, and disease burden attributable to residential wood combustion was estimated to be 3400 disability-adjusted life years (DALY) and 200 deaths. Disease burden decreased by 8% in the 2030 baseline scenario and by an additional 63% in the maximum feasible reduction scenario. Informational campaigns and improvement of the sauna stove stock were assessed to be the most feasible abatement measures to be implemented in national air quality policies.
  • Kupiainen, Kaarle (Finnish Environment Institute, 2007)
    Monographs of the Boreal Environment Research 26
    Vehicles affect the concentrations of ambient airborne particles through exhaust emissions, but particles are also formed in the mechanical processes in the tire-road interface, brakes, and engine. Particles deposited on or in the vicinity of the road may be re-entrained, or resuspended, into air through vehicle-induced turbulence and shearing stress of the tires. A commonly used term for these particles is ?road dust?. The processes affecting road dust emissions are complex and currently not well known.Road dust has been acknowledged as a dominant source of PM10 especially during spring in the sub-arctic urban areas, e.g. in Scandinavia, Finland, North America and Japan. The high proportion of road dust in sub-arctic regions of the world has been linked to the snowy winter conditions that make it necessary to use traction control methods. Traction control methods include dispersion of traction sand, melting of ice with brine solutions, and equipping the tires with either metal studs (studded winter tires), snow chains, or special tire design (friction tires). Several of these methods enhance the formation of mineral particles from pavement wear and/or from traction sand that accumulate in the road environment during winter. When snow and ice melt and surfaces dry out, traffic-induced turbulence makes some of the particles airborne.A general aim of this study was to study processes and factors underlying and affecting the formation and emissions of road dust from paved road surfaces. Special emphasis was placed on studying particle formation and sources during tire road interaction, especially when different applications of traction control, namely traction sanding and/or winter tires were in use. Respirable particles with aerodynamic diameter below 10 micrometers (PM10) have been the main concern, but other size ranges and particle size distributions were also studied. The following specific research questions were addressed: i) How do traction sanding and physical properties of the traction sand aggregate affect formation of road dust? ii) How do studded tires affect the formation of road dust when compared with friction tires? iii) What are the composition and sources of airborne road dust in a road simulator and during a springtime road dust episode in Finland? iv) What is the size distribution of abrasion particles from tire-road interaction? The studies were conducted both in a road simulator and in field conditions.The test results from the road simulator showed that traction sanding increased road dust emissions, and that the effect became more dominant with increasing sand load. A high percentage of fine-grained anti-skid aggregate of overall grading increased the PM10 concentrations. Anti-skid aggregate with poor resistance to fragmentation resulted in higher PM levels compared with the other aggregates, and the effect became more significant with higher aggregate loads. Glaciofluvial aggregates tended to cause higher particle concentrations than crushed rocks with good fragmentation resistance. Comparison of tire types showed that studded tires result in higher formation of PM emissions compared with friction tires. The same trend between the tires was present in the tests with and without anti-skid aggregate. This finding applies to test conditions of the road simulator with negligible resuspension.Source and composition analysis showed that the particles in the road simulator were mainly minerals and originated from both traction sand and pavement aggregates. A clear contribution of particles from anti-skid aggregate to ambient PM and dust deposition was also observed in urban conditions. The road simulator results showed that the interaction between tires, anti-skid aggregate and road surface is important in dust production and the relative contributions of these sources depend on their properties. Traction sand grains are fragmented into smaller particles under the tires, but they also wear the pavement aggregate. Therefore particles from both aggregates are observed. The mass size distribution of traction sand and pavement wear particles was mainly coarse, but fine and submicron particles were also present.
  • Wahlström, Johanna; Karvosenoja, Niko; Porvari, Petri (Finnish Environment Institute, 2006)
    Reports of the Finnish Environment Institute 8/2006
  • Paunu, Ville-Veikko; Karvosenoja, Niko; Segersson, David; López-Aparicio, Susana; Nielsen, Ole-Kenneth; Plejdrup, Marlene Schmidt; Thorsteinsson, Throstur; Niemi, Jarkko V.; Vo, Dam Thanh; Denier van der Gon, Hugo A.C.; Brandt, Jørgen; Geels, Camilla (Elsevier, 2021)
    Atmospheric Environment, 264 (2021), 118712
    Residential wood combustion (RWC) is a major source of air pollutants in the Nordic and many other countries. The emissions of the pollutants have been estimated with inventories on several scopes, e.g. local and national. An important aspect of the inventories is the spatial distribution of the emissions, as it has an effect on health impact assessments. In this study, we present a novel residential wood combustion emission inventory for the Nordic countries based on national inventories and new gridding of the emissions. We compare the emissions of the Nordic inventory, and especially their spatial distribution, to local assessments and European level TNO-newRWC-inventory to assess the spatial proxies used. Common proxies used in the national inventories in the Nordic countries were building data on locations and primary heating methods and questionnaire-based wood use estimates for appliances or primary heating methods. Chimney sweeper register data was identified as good proxy data, but such data may not be available in an applicable format. Comparisons of national inventories to local assessments showed the possibility to achieve similar spatial distributions through nation-wide methods as local ones. However, this won't guarantee that the emissions are similar. Comparison to the TNO-newRWC-inventory revealed the importance of how differences between urban and rural residential wood combustion are handled. The comparison also highlighted the importance of local characteristics of residential wood combustion in the spatial distribution of emissions.
  • Stojiljkovic, Ana; Kauhaniemi, Mari; Kukkonen, Jaakko; Kupiainen, Kaarle; Karppinen, Ari; Denby, Bruce Rolstad; Kousa, Anu; Niemi, Jarkko V.; Ketzel, Matthias (Copernicus Publications, 2019)
    Atmospheric Chemistry and Physics
    We have numerically evaluated how effective selected potential measures would be for reducing the impact of road dust on ambient air particulate matter (PM10). The selected measures included a reduction of the use of studded tyres on light-duty vehicles and a reduction of the use of salt or sand for traction control. We have evaluated these measures for a street canyon located in central Helsinki for four years (2007–2009 and 2014). Air quality measurements were conducted in the street canyon for two years, 2009 and 2014. Two road dust emission models, NORTRIP (NOn-exhaust Road TRaffic Induced Particle emissions) and FORE (Forecasting Of Road dust Emissions), were applied in combination with the Operational Street Pollution Model (OSPM), a street canyon dispersion model, to compute the street increments of PM10 (i.e. the fraction of PM10 concentration originating from traffic emissions at the street level) within the street canyon. The predicted concentrations were compared with the air quality measurements. Both road dust emission models reproduced the seasonal variability of the PM10 concentrations fairly well but under-predicted the annual mean values. It was found that the largest reductions of concentrations could potentially be achieved by reducing the fraction of vehicles that use studded tyres. For instance, a 30 % decrease in the number of vehicles using studded tyres would result in an average decrease in the non-exhaust street increment of PM10 from 10 % to 22 %, depending on the model used and the year considered. Modelled contributions of traction sand and salt to the annual mean non-exhaust street increment of PM10 ranged from 4 % to 20 % for the traction sand and from 0.1 % to 4 % for the traction salt. The results presented here can be used to support the development of optimal strategies for reducing high springtime particulate matter concentrations originating from road dust. Short summary Nordic countries experience the deterioration of air quality in springtime due to high PM10 concentrations. Non-exhaust emissions from vehicular traffic are regarded as the most significant source of particulate air pollution during this time of year. The results from this study demonstrate the fact that changes in winter tyre types and adjustments to road maintenance could substantially reduce non-exhaust emissions.