Browsing by Subject "pienhiukkaset"

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  • Sanmark, E; Oksanen, L A H; Rantanen, N; Lahelma, M; Anttila, V-J; Lehtonen, L; Hyvärinen, A; Geneid, A (Cambridge University Press, 2022)
    Journal of laryngology and otology
    Objective. Coronavirus disease 2019 has highlighted the lack of knowledge on aerosol exposure during respiratory activity and aerosol-generating procedures. This study sought to determine the aerosol concentrations generated by coughing to better understand, and to set a standard for studying, aerosols generated in medical procedures. Methods. Aerosol exposure during coughing was measured in 37 healthy volunteers in the operating theatre with an optical particle sizer, from 40 cm, 70 cm and 100 cm distances. Results. Altogether, 306 volitional and 15 involuntary coughs were measured. No differences between groups were observed. Conclusion. Many medical procedures are expected to generate aerosols; it is unclear whether they are higher risk than normal respiratory activity. The measured aerosol exposure can be used to determine the risk for significant aerosol generation during medical procedures. Considerable variation of aerosol generation during cough was observed between individuals, but whether cough was volitional or involuntary made no difference to aerosol production
  • Calderón, Silvia M.; Tonttila, Juha; Buchholz, Angela; Joutsensaari, Jorma; Komppula, Mika; Leskinen, Ari; Hao, Liqing; Moisseev, Dmitri; Pullinen, Iida; Tiitta, Petri; Xu, Jian; Virtanen, Annele; Kokkola, Harri; Romakkaniemi, Sami (Copernicus Publ., 2022)
    Atmospheric chemistry and physics
    We carried out a closure study of aerosol-cloud interactions during stratocumulus formation using a large eddy simulation model UCLALES-SALSA and observations from the 2020 cloud sampling campaign at the Puijo SMEAR IV station in Kuopio, Finland. The unique observational setup combining in situ and cloud remote sensing measurements allowed a closer look into the aerosol size-composition dependence of droplet activation and droplet growth in turbulent boundary layer driven by surface forcing and radiative cooling. UCLALES-SALSA uses spectral bin microphysics for aerosols and hydrometeors and incorporates a full description of their interactions into the turbulent-convective radiation-dynamical model of stratocumulus. Based on our results, the model successfully described the probability distribution of updraft velocities and consequently the size dependency of aerosol activation into cloud droplets, and further recreated the size distributions for both interstitial aerosol and cloud droplets. This is the first time such a detailed closure is achieved not only accounting for activation of cloud droplets in different updrafts, but also accounting for processes evaporating droplets and drizzle production through coagulation-coalescence. We studied two cases of cloud formation, one diurnal (24 September 2020) and one nocturnal (31 October 2020), with high and low aerosol loadings, respectively. Aerosol number concentrations differ more than 1 order of magnitude between cases and therefore, lead to cloud droplet number concentration (CDNC) values which range from less than 100cm-3 up to 1000cm-3. Different aerosol loadings affected supersaturation at the cloud base, and thus the size of aerosol particles activating to cloud droplets. Due to higher CDNC, the mean size of cloud droplets in the diurnal-high aerosol case was lower. Thus, droplet evaporation in downdrafts affected more the observed CDNC at Puijo altitude compared to the low aerosol case. In addition, in the low aerosol case, the presence of large aerosol particles in the accumulation mode played a significant role in the droplet spectrum evolution as it promoted the drizzle formation through collision and coalescence processes. Also, during the event, the formation of ice particles was observed due to subzero temperature at the cloud top. Although the modeled number concentration of ice hydrometeors was too low to be directly measured, the retrieval of hydrometeor sedimentation velocities with cloud radar allowed us to assess the realism of modeled ice particles. The studied cases are presented in detail and can be further used by the cloud modellers to test and validate their models in a well-characterized modelling setup. We also provide recommendations on how increasing amount of information on aerosol properties could improve the understanding of processes affecting cloud droplet number and liquid water content in stratiform clouds.
  • Karl, Matthias; Pirjola, Liisa; Grönholm, Tiia; Kurppa, Mona; Anand, Srinivasan; Zhang, Xiaole; Held, Andreas; Sander, Rolf; Dal Maso, Miikka; Topping, David; Jiang, Shuai; Kangas, Leena; Kukkonen, Jaakko (Copernicus Publ., 2022)
    Geoscientific model development
    Numerical models are needed for evaluating aerosol processes in the atmosphere in state-of-the-art chemical transport models, urban-scale dispersion models, and climatic models. This article describes a publicly available aerosol dynamics model, MAFOR (Multicomponent Aerosol FORmation model; version 2.0); we address the main structure of the model, including the types of operation and the treatments of the aerosol processes. The model simultaneously solves the time evolution of both the particle number and the mass concentrations of aerosol components in each size section. In this way, the model can also allow for changes in the average density of particles. An evaluation of the model is also presented against a high-resolution observational dataset in a street canyon located in the centre of Helsinki (Finland) during afternoon traffic rush hour on 13 December 2010. The experimental data included measurements at different locations in the street canyon of ultrafine particles, black carbon, and fine particulate mass PM1. This evaluation has also included an intercomparison with the corresponding predictions of two other prominent aerosol dynamics models, AEROFOR and SALSA. All three models simulated the decrease in the measured total particle number concentrations fairly well with increasing distance from the vehicular emission source. The MAFOR model reproduced the evolution of the observed particle number size distributions more accurately than the other two models. The MAFOR model also predicted the variation of the concentration of PM1 better than the SALSA model. We also analysed the relative importance of various aerosol processes based on the predictions of the three models. As expected, atmospheric dilution dominated over other processes; dry deposition was the second most significant process. Numerical sensitivity tests with the MAFOR model revealed that the uncertainties associated with the properties of the condensing organic vapours affected only the size range of particles smaller than 10 nm in diameter. These uncertainties therefore do not significantly affect the predictions of the whole of the number size distribution and the total number concentration. The MAFOR model version 2 is well documented and versatile to use, providing a range of alternative parameterizations for various aerosol processes. The model includes an efficient numerical integration of particle number and mass concentrations, an operator splitting of processes, and the use of a fixed sectional method. The model could be used as a module in various atmospheric and climatic models.
  • 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).
  • Chen, Gang; Canonaco, Francesco; Tobler, Anna; Aas, Wenche; Alastuey, Andres; Allan, James; Atabakhsh, Samira; Aurela, Minna; Baltensperger, Urs; Bougiatioti, Aikaterini; De Brito, Joel F.; Ceburnis, Darius; Chazeau, Benjamin; Chebaicheb, Hasna; Daellenbach, Kaspar R.; Ehn, Mikael; El Haddad, Imad; Eleftheriadis, Konstantinos; Favez, Olivier; Flentje, Harald; Font, Anna; Fossum, Kirsten; Freney, Evelyn; Gini, Maria; Green, David C; Heikkinen, Liine; Herrmann, Hartmut; Kalogridis, Athina-Cerise; Keernik, Hannes; Lhotka, Radek; Lin, Chunshui; Lunder, Chris; Maasikmets, Marek; Manousakas, Manousos I.; Marchand, Nicolas; Marin, Cristina; Marmureanu, Luminita; Mihalopoulos, Nikolaos; Močnik, Griša; Nęcki, Jaroslaw; O'Dowd, Colin; Ovadnevaite, Jurgita; Peter, Thomas; Petit, Jean-Eudes; Pikridas, Michael; Matthew Platt, Stephen; Pokorná, Petra; Poulain, Laurent; Priestman, Max; Riffault, Véronique; Rinaldi, Matteo; Różański, Kazimierz; Schwarz, Jaroslav; Sciare, Jean; Simon, Leïla; Skiba, Alicja; Slowik, Jay G.; Sosedova, Yulia; Stavroulas, Iasonas; Styszko, Katarzyna; Teinemaa, Erik; Timonen, Hilkka; Tremper, Anja; Vasilescu, Jeni; Via, Marta; Vodička, Petr; Wiedensohler, Alfred; Zografou, Olga; Cruz Minguillón, María; Prévôt, André S.H. (Pergamon., 2022)
    Environment international
    Organic aerosol (OA) is a key component of total submicron particulate matter (PM1), and comprehensive knowledge of OA sources across Europe is crucial to mitigate PM1 levels. Europe has a well-established air quality research infrastructure from which yearlong datasets using 21 aerosol chemical speciation monitors (ACSMs) and 1 aerosol mass spectrometer (AMS) were gathered during 2013–2019. It includes 9 non-urban and 13 urban sites. This study developed a state-of-the-art source apportionment protocol to analyse long-term OA mass spectrum data by applying the most advanced source apportionment strategies (i.e., rolling PMF, ME-2, and bootstrap). This harmonised protocol was followed strictly for all 22 datasets, making the source apportionment results more comparable. In addition, it enables quantification of the most common OA components such as hydrocarbon-like OA (HOA), biomass burning OA (BBOA), cooking-like OA (COA), more oxidised-oxygenated OA (MO-OOA), and less oxidised-oxygenated OA (LO-OOA). Other components such as coal combustion OA (CCOA), solid fuel OA (SFOA: mainly mixture of coal and peat combustion), cigarette smoke OA (CSOA), sea salt (mostly inorganic but part of the OA mass spectrum), coffee OA, and ship industry OA could also be separated at a few specific sites. Oxygenated OA (OOA) components make up most of the submicron OA mass (average = 71.1%, range from 43.7 to 100%). Solid fuel combustion-related OA components (i.e., BBOA, CCOA, and SFOA) are still considerable with in total 16.0% yearly contribution to the OA, yet mainly during winter months (21.4%). Overall, this comprehensive protocol works effectively across all sites governed by different sources and generates robust and consistent source apportionment results. Our work presents a comprehensive overview of OA sources in Europe with a unique combination of high time resolution (30–240 min) and long-term data coverage (9–36 months), providing essential information to improve/validate air quality, health impact, and climate models.
  • Tohka, Antti; Karvosenoja, Niko (Finnish Environment Institute, 2006)
    Reports of the Finnish Environment Institute 21/2006
  • Tissari, Jarkko; Väätäinen, Sampsa; Leskinen, Jani; Savolahti, Mikko; Lamberg, Heikki; Kortelainen, Miika; Karvosenoja, Niko; Sippula, Olli (MDPI, 2019)
    Atmosphere 2019; 10(12):775
    Sauna Stoves (SS) are simple wood combustion appliances used mainly in Nordic countries. They generate emissions that have an impact on air quality and climate. In this study, a new measurement concept for comparing the operation, thermal efficiency, and real-life fine particle and gaseous emissions of SS was utilized. In addition, a novel, simple, and universal emission calculation procedure for the determination of nominal emission factors was developed for which the equations are presented for the first time. Fine particle and gaseous concentrations from 10 different types of SS were investigated. It was found that each SS model was an individual in relation to stove performance: stove heating time, air-to-fuel ratio, thermal efficiency, and emissions. Nine-fold differences in fine particle mass (PM1) concentrations, and about 90-fold differences in concentrations of polycyclic aromatic hydrocarbons (PAH) were found between the SS, when dry (11% moisture content) birch wood was used. By using moist (18%) wood, particle number and carbon monoxide concentrations increased, but interestingly, PM1, PAH, and black carbon (BC) concentrations clearly decreased, when comparing to dry wood. E.g., PAH concentrations were 5.5–9.6 times higher with dry wood than with moist wood. Between wood species, 2–3-fold maximum differences in the emissions were found, whereas about 1.5-fold differences were observed between bark-containing and debarked wood logs. On average, the emissions measured in this study were considerably lower than in previous studies and emission inventories. This suggests that overall the designs of sauna stoves available on the market have improved during the 2010s. The findings of this study were used to update the calculation scheme behind the inventories, causing the estimates for total PM emissions from SS in Finland to decrease. However, wood-fired sauna stoves are still estimated to be the highest individual emission source of fine particles and black carbon in Finland.
  • Karvosenoja, Niko; Klimont, Zbigniew; Tohka, Antti; Johansson, Matti (Finnish Environment Institute, 2006)
    The Finnish Environment 46/2006
    Fine particulate matter (PM2.5) in the atmosphere have been associated with severe human health effects. This report explores future emissions of primary PM2.5, their reduction potential and related reduction costs in Finland. One activity pathway of 2020 of the Finnish Climate Strategy was studied with two different PM emission control utilization scenarios: (1) "Baseline" which involves PM control technology utilization complying with current legislation, and (2) "Reduction" which assumes the use of maximum technically and economically feasible emission reduction measures. The studied sectors included stationary combustion and industrial activities. The work was performed using the Finnish Regional Emission Scenario (FRES) model of Finnish environment institute (SYKE). Total emission reduction potential below "Baseline" was estimated at 6.7 Gg(PM2.5) a-1, or 22% of the total emissions. The biggest relatively cost-efficient reductions (marginal cost below 5000 € Mg-1) can be achieved by the use of small electrostatic precipitators (ESPs) in domestic wood log boilers, 2.0 Gg a-1. In large-scale combustion installations in power plants and industry the reduction of 1.2 Gg a-1 is possible by fabric filter installations instead of ESPs. A comparable reduction with slightly higher costs can be achieved in small (below 5 MWth) industrial boilers by the introduction of ESPs. For industrial processes potential occurs in few individual plants. The uncertainties in emission reduction and cost estimates are biggest for domestic combustion and industrial processes. This report presents cost-efficiency estimates of future emission reductions per mass of PM2.5 reduced. However, the magnitude of health benefits gained from emission reductions are different for different emission sources, depending on e.g. the altitude of emission release, the emission location in relation to the location of population etc. The results of this study are used in the integrated assessment modeling framework developed in the KOPRA project in order to link the information of emission reductions and costs, atmospheric dispersion and induced health impacts.
  • Savolahti, Mikko; Karvosenoja, Niko; Kupiainen, Kaarle; Paunu, Ville-Veikko; Sippola, Olli; Jokiniemi, Jorma (Suomen ympäristökeskus, 2009)
    Suomen ympäristökeskuksen raportteja 30/2009
  • Taka, Maija; Sillanpää, Nora; Niemi, Tero; Warsta, Lassi; Kokkonen, Teemu; Setälä, Heikki (Elsevier, 2022)
    Science of the total environment
    Urban hydrology is characterized by increased runoff and various pollutant sources. We studied the spatio-temporal patterns of stormwater metal (Al, V, Cr, Mn, Fe, Cu, Zn, and Pb) concentrations and loads in five urbanized and one rural catchment in Southern Finland. The two-year continuous monitoring revealed a non-linear seasonal relationship between catchment urban intensity and metal export. For runoff, seasonal variation decreased with increasing imperviousness. The most urbanized catchments experienced greatest temporal variation in metal concentrations: the annual Cu and Zn loads in most of the studied urbanized catchments were up to 86 times higher compared to the rural site, whereas Fe loads in the urbanized catchments were only circa 29% of the rural load. Total metal levels were highest in the winter, whereas the winter peak of dissolved metal concentrations was less pronounced. The collection of catchment characteristics explained well the total metal concentrations, whereas for the dissolved concentrations the explanatory power was weaker. Our catchment-scale analysis revealed a mosaic of mainly diffuse pollutant sources and calls for catchment-scale management designs. As urban metal export occurred across seasons, solutions that operate also in cold conditions are needed. Highlights • Impact of urban land use on metal export was studied by monitoring six catchments. • Continuous monitoring, automatic sampling and statistical modelling were performed. • Urban intensity increased seasonality in concentrations, especially for Zn and Cu. • Highest total metal load occurred in winter; seasonality in dissolved metals was modest.
  • Saarnio, Karri; Vestenius, Mika; Kyllönen, Katriina (Ilmatieteen laitos - Finnish Meteorological Institute, 2021)
    Raportteja - Rapporter - Reports 2021:2
    Kansallinen ilmanlaadun vertailulaboratorio varmistaa Suomessa tehtävien ilmanlaatumittausten korkean laadun tekemällä ilmanlaatumittausten auditointeja ja vertailumittauksia. Tässä hankkeessa arvioitiin hiukkasmittausten vaatimuksenmukaisuutta keskittyen erityisesti keskimääräisen altistumisindikaattorin (AEI) määrittämiseen käytettävään mittaukseen. Tutkimuksessa arvioitiin Helsingin Kalliossa mitatun PM2,5-altistumisindikaattorin mittauksen tulosten soveltuvuutta ja edustavuutta Suomessa. Havaittiin, että Kallion mittaus edustaa hyvin keskimääräistä pienhiukkasaltistusta sekä pienhiukkaspitoisuuden vuositrendiä Suomessa. Lisäksi vuodesta 2015 eteenpäin Suomen kaupunkitausta-asemilla tehtyjen PM2,5-mittausten keskiarvot niin asemakohtaisesti kuin asemien yhteisenä keskiarvona alittavat kokonaisuudessaan vuoden 2020 keskimääräisen altistumisindikaattorin enimmäisarvon 8,5 µg/m3, jota käytetään altistumisen vähennystavoitteen arvioinnissa. AEI-mittaukseen käytetyn TEOM 1405 -hiukkasmonitorin mittaustuloksia vertailtiin Kalliossa menetelmästandardin SFS-EN 12341:2014 mukaisella vertailumenetelmällä saatuihin tuloksiin. Havaittiin, että AEI-laskentaan käytettävä Kallion TEOM 1405 -laite täyttää niukasti standardissa määritetyn 25 %:n epävarmuusvaatimuksen ja sillä tehtävän mittauksen laatu riittää altistumisindikaattorin määrittämiseen, vaikka vertailtavat pitoisuudet olivat yleisesti ottaen pieniä eikä menetelmästandardin SFS-EN 16450:2017 mukaisen vertailumittauksen pitoisuusvaatimus täyttynyt vertailujaksolla korkeiden pitoisuuksien puuttuessa. Tässä raportissa esitellään myös tulokset jatkuvatoimisille hiukkasmittalaitteille järjestetyistä vertailumittauksista Virolahdella ja Helsingissä sekä PM10- että PM2,5-hiukkaskokojakeelle sekä näiden lisäksi Kuopiossa ja Lahdessa PM2,5-hiukkaskokojakeelle. Vertailumittauksista saatujen tulosten perusteella määritettiin ensimmäistä kertaa korjauskertoimet FIDAS 200 -hiukkasmittalaitteen PM10- ja PM2,5-mittaukselle Suomessa. Tulosten perusteella FIDAS 200 -hiukkasmonitori soveltuu ulkoilman PM10- ja PM2,5-hiukkaskokojakeiden mittaukseen Suomessa käyttäen tässä raportissa esitettyjä korjauskertoimia, vaikkakin on huomioitava, että kertoimet eivät täytä ekvivalenttisuuden osoittamiselle asetettuja vaatimuksia. Kyseisiä kertoimia on kuitenkin suositeltavaa käyttää siihen asti, kunnes ekvivalenttisuus on osoitettu seuraavassa ekvivalenttisuuden osoittamiskampanjassa. Kahta muuta jatkuvatoimista laitetta (SHARP 5030 ja TEOM 1405) verrattiin referenssikeräimeen Virolahdella ja Helsingissä. Havaittiin, että Kuopion vertailumittauksessa 2014–2015 eri laitteille määritetyt korjauskertoimet eivät aina sovellu eri paikoissa ja eri vuodenaikoina PM10- ja PM2,5-hiukkaspitoisuuksien mittauksiin, koska mittauspaikat ja niiden olosuhteet vaihtelevat. Tämän takia vertailulaboratorio esittää ekvivalenttisuuden osoitusta viiden vuoden välein sekä jatkuvaa ohjelmaa käytettävien kertoimien soveltuvuuden osoittamiseksi paikallisilla vertailumittauksilla, joissa jatkuvatoimisten hiukkasmonitorien mittaustuloksia verrataan vertailumenetelmää vastaan eri paikoissa ja vaihtelevissa olosuhteissa jatkuvana kampanjana pitempiaikaisesti, puolesta vuodesta vuoteen kestävillä paikallisilla vertailuilla. Näillä ns. ongoing-mittauksilla voidaan osaltaan varmentaa Suomessa mitattavien PM10- ja PM2,5-hiukkasmittausten laatu ja vertailukelpoisuus myös varsinaisten ekvivalenttisuuden osoittamiseen soveltuvien vertailumittauskampanjoiden välillä.
  • Kouki, Kerttu (Helsingfors universitet, 2017)
    Tutkimukseni tavoitteena oli selvittää, miten kasviperäisten hiukkasten määrä muuttuu Amazonilla ilmaston lämmetessä ja miten se vaikuttaa Amazonin ilmastoon. Hallitustenvälisen ilmastonmuutospaneelin (IPCC) mukaan merkittävimmät epävarmuudet ilmastonmuutoksessa liittyvät aerosoleihin, ja luonnolliset aerosolit aiheuttavat suuremman epävarmuuden ilmastoon kuin antropogeeniset aerosolit. Amazonin sademetsä on erityisen sopiva kasviperäisten hiukkasten tutkimiseen ja tutkimuskysymykseni kannalta kiinnostava, sillä etenkin sadekaudella valtaosa aerosoleista on kasviperäisiä. Tutkimusaineistona käytettiin satelliittien keräämiä havaintoja, joiden avulla määritettiin lämpötila (LST, engl. land surface temperature), aerosolien määrä ilmakehässä (AOD, engl. aerosol optical depth) sekä eri pienhiukkaslähteitä. Samat lähteet, jotka tuottavat pienhiukkasia ilmakehään, päästävät sinne myös hivenkaasuja. Erilaiset lähteet tuottavat erilaisia pienhiukkasia ja kaasuja, joten yhdistämällä havaintoja pienhiukkasista ja hivenkaasuista voidaan niiden lähteet selvittää luotettavammin. LST ja AOD määritettiin AATSR:n (Advanced Along-Track Scanning Radiometer) havaintojen avulla. Pienhiukkaslähteiden tunnistamiseen käytettiin OMI:n (Ozone Monitoring Instrument) keräämiä havaintoja typpidioksidista (NO2) ja formaldehydistä (HCHO) sekä AIRS:n (Atmospheric Infrared Sounder) havaintoja hiilimonoksidista (CO). Tulosteni mukaan pienhiukkasten määrä vaihtelee Amazonilla vuoden aikana varsin paljon: sadekaudella hiukkasten määrä on hyvin vähäinen, kun taas kuivalla kaudella määrä kasvaa moninkertaiseksi laajojen metsäpalojen seurauksena. Voisi olettaa, että lämpimämpinä aikoina myös metsäpalot lisääntyisivät, mutta tulosten mukaan palokaudella pienhiukkasten määrä pienenee lämpötilan noustessa. Suuri osa paloista on kuitenkin ihmisen sytyttämiä, joten myös ihmistoiminnalla on merkittävä vaikutus palokauden hiukkasiin. Hiilimonoksidia ja formaldehydiä muodostuu sadekaudella pääosin kasviperäisistä lähteistä, ja erityisesti hiilimonoksidin määrän havaittiin korreloivan positiivisesti lämpötilan kanssa, mikä viittaa kasviperäisten hiukkasten määrän kasvuun lämpötilan noustessa. Sadekaudella suurin osa hiukkasista on kasviperäisiä ja silloin AOD:n lämpötilariippuvuus on 0,008 ± 0,015 K-1, joten kasviperäisten hiukkasten suora säteilyvaikutus on siten –0,22 ± 0,40 Wm-2K-1 pilvettömälle taivaalla ja –0,08 ± 0,16 Wm-2K-1, kun pilvien osuus on 60 % koko taivaasta. Lämpötilan noustessa kasviperäiset hiukkaset siis todennäköisesti aiheuttavat negatiivisen säteilypakotteen ja siten hillitsevät ilmaston lämpenemistä. Toisaalta tulokseni kuitenkin osoittavat, että metsäpalot ovat hiukkasten merkittävin lähde Amazonilla, sillä metsäpalojen yhteydessä esiintyy merkittävästi luonnollista tasoa enemmän hiukkasia. Metsäpaloista syntyneet hiukkaset todennäköisesti määrittelevätkin AOD:n muutokset myös tulevaisuudessa.
  • Korhonen, Antti; Lehtomäki, Heli; Rumrich, Isabell; Karvosenoja, Niko; Paunu, Ville-Veikko; Kupiainen, Kaarle; Sofiev, Mikhail; Palamarchuk, Yuliia; Kukkonen, Jaakko; Kangas, Leena; Karppinen, Ari; Hänninen, Otto (Springer Nature, 2019)
    Air Quality, Atmosphere & Health
    Health effect estimates depend on the methods of evaluating exposures. Due to non-linearities in the exposure-response relationships, both the predicted mean exposures as well as its spatial variability are significant. The aim of this work is to systematically quantify the impact of the spatial resolution on population-weighted mean concentration (PWC), its variance, and mortality attributable to fine particulate matter (PM2.5) exposure in Finland in 2015. The atmospheric chemical transport model SILAM was used to estimate the ambient air PM2.5 concentrations at 0.02° longitudinal × 0.01° latitudinal resolution (ca. 1 km), including both the national PM2.5 emissions and the long-range transport. The decision-support model FRES source-receptor matrices applied at 250-m resolution was used to model the ambient air concentrations of primary fine particulate matter (PPM2.5) from local and regional sources up to 10 km and 20 km distances. Numerical averaging of population and concentrations was used to produce the results for coarser resolutions. Population-weighted PM2.5 concentration was 11% lower at a resolution of 50 km, compared with the corresponding computations at a resolution of 1 km. However, considering only the national emissions, the influences of spatial averaging were substantially larger. The average population-weighted local PPM2.5 concentration originated from Finnish sources was 70% lower at a resolution of 50 km, compared with the corresponding result obtained using a resolution of 250 m. The sensitivity to spatial averaging, between the finest 250-m and the coarsest 50-km resolution, was highest for the emissions of PPM2.5 originated from national vehicular traffic (about 80% decrease) and lowest for the national residential combustion (60% decrease). Exposure estimates in urban areas were more sensitive to the changes of model resolution (14% and 74% decrease for PM2.5 and local PPM2.5, respectively), compared with estimates in rural areas (2% decrease for PM2.5 and 36% decrease for PPM2.5). We conclude that for the evaluation of the health impacts of air pollution, the resolution of the model computations is an important factor, which can potentially influence the predicted health impacts by tens of percent or more, especially when assessing the impacts of national emissions.
  • Holopainen, E.; Kokkola, H.; Faiola, C.; Laakso, A.; Kühn, T. (John Wiley & Sons, 2022)
    Journal of geophysical research : atmospheres
    Plant stress in a changing climate is predicted to increase plant volatile organic compound (VOC) emissions and thus can affect the formed secondary organic aerosol (SOA) concentrations, which in turn affect the radiative properties of clouds and aerosol. However, global aerosol-climate models do not usually consider plant stress induced VOCs in their emission schemes. In this study, we modified the monoterpene emission factors in biogenic emission model to simulate biotic stress caused by insect herbivory on needleleaf evergreen boreal and broadleaf deciduous boreal trees and studied the consequent effects on SOA formation, aerosol-cloud interactions as well as direct radiative effects of formed SOA. Simulations were done altering the fraction of stressed and healthy trees in the latest version of ECHAM-HAMMOZ (ECHAM6.3-HAM2.3- MOZ1.0) global aerosol-climate model. Our simulations showed that increasing the extent of stress to the aforementioned tree types, substantially increased the SOA burden especially over the areas where these trees are located. This indicates that increased VOC emissions due to increasing stress enhance the SOA formation via oxidation of VOCs to low VOCs. In addition, cloud droplet number concentration at the cloud top increased with increasing extent of biotic stress. This indicates that as SOA formation increases, it further enhances the number of particles acting as cloud condensation nuclei. The increase in SOA formation also decreased both all-sky and clear-sky radiative forcing. This was due to a shift in particle size distributions that enhanced aerosol reflecting and scattering of incoming solar radiation.
  • Antturi, Jim (Helsingin yliopisto, 2015)
    The International Maritime Organization's sulfur emissions regulations for shipping were implemented in the European Union with the so called Sulfur Directive. According to the International Convention for the Prevention of Pollution from Ships (MARPOL), as of January 1, 2015, in Sulfur Emission Control Areas (SECAs) the maximum sulfur content in maritime fuel is lowered to 0.1%. In Europe the Baltic Sea, the English Channel and the North Sea are declared SECAs, where the standard was previously 1.0%. The current worldwide non-SECA standard is 3.5% which will be lowered to 0.5% by 2020. This study examines the net benefits of reducing shipping-based sulfur emissions and the effect on industrial competitiveness for Finland. In order to do this, abatement costs as well as monetized health benefits related to improved air quality are calculated. The effect on competitiveness is defined by comparing the figures obtained with the hypothetical case in which the Baltic Sea had not been declared SECA and 0.5% regulation had been imposed. In this study, shipowners adapt to the regulation by switching to low-sulfur fuel or by installing a sulfur scrubber. A net present value comparison between low sulfur fuel and a sulfur scrubber is conducted individually for each ship visiting Finland and then individual costs are aggregated to industry-wide costs. Health benefits for Finland are calculated for emissions reductions applied to Baltic Sea shipping as whole. Reduced sulfur emissions lead to lowered ambient concentrations of fine particulate matter (PM2.5) which has a positive impact on human health. The analysis conducted takes into account the effect PM2.5 has on the incidences of cardiovascular disease, lung cancer, chronic obstructive pulmonary disease and restricted activity days. These effects are measured in one figure in Disability Adjusted Life Years (DALYs) and monetized by multiplying by the Value of a Life Year (VOLY). The results suggest that the annual benefits of emissions reduction are expected to be circa 246 saved DALYs or monetized €12 million. The average annual abatement cost for Finland is approximately €228 million which indicates negative net benefits for the policy. Assuming that Finland will bear 100% of the costs, the same figure also represents the effect on competitiveness. When the global 0.5% cap comes into effect the impact on competitiveness decreases to an annual €93 million. The results imply that the abatement costs are lower than previously thought and the effect on competitiveness is milder than expected. A partial sensitivity analysis does not change the ratio between the costs and the benefits.
  • Lehtomäki, Heli; Karvosenoja, Niko; Paunu, Ville-Veikko; Korhonen, Antti; Hänninen, Otto; Tuomisto, Jouni; Karppinen, Ari; Kukkonen, Jaakko; Tainio, Marko (Suomen ympäristökeskus, 2021)
    Suomen ympäristökeskuksen raportteja 16/2021
    Liikenteellä on sekä positiivisia että negatiivia terveysvaikutuksia. Tässä työssä arvoimme liikenteen aiheuttamat terveysvaikutukset Suomessa ottaen huomioon ilman pienhiukkasaltistuksen, melualtistuksen ja liikenneonnettomuuksien aiheuttamat terveyshaitat sekä aktiivisen liikkumisen (kävelyn ja pyöräilyn) terveyshyödyt. Terveysvaikutusten arviointi tehtiin käyttäen tautitaakkamenetelmiä. Liikenteen terveyshaitat olivat 16 200 DALYa (Disability Adjusted Life Years; yksi DALY kuvaa yhtä sairauden tai onnettomuuden vuoksi menetettyä haittapainotettua vuotta) vuonna 2015. Liikenneonnettomuudet aiheuttivat suurimman osan (60 %) liikenteen terveyshaitoista. Pienhiukkasten osuus terveyshaitoista oli 20 % ja liikennemelun 19 %. Pienhiukkasten osalta tarkasteltiin vain kotimaisia primäärisiä pienhiukkaspäästöjä, eli suoraan päästölähteestä peräisin olevia hiukkasia. Aktiivisen liikkumisen terveyshyödyt olivat lähes kaksinkertaiset liikenteen terveyshaittoihin verrattuna (-31 400 DALY). Kaupunkitasolla tarkasteltaessa onnettomuuksien rooli oli selvästi pienempi kuin kansallisella tasolla ja vastaavasti melun suhteellinen merkitys kasvoi. Melun tautitaakka-arvio perustui kymmenen suuren kaupungin ympäristömeludirektiivin (2002/49/EY) mukaisesti raportoimiin melualtistuksiin. Koko maan osalta melun tautitaakkaa ei pystytty arvioimaan kattavasti, koska direktiiviin mukaisia altistustietoja oli saatavilla vain näille kymmenelle kaupungille. Melun altistusarvioinnin kattavuuden lisäksi tunnistimme myös muita jatkotutkimustarpeita muun muassa liittyen puuttuviin riskitekijöihin (typpidioksidi NO2, kaasumaisista päästöistä muodostuvat sekundaariset pienhiukkaset) ja sairastavuuden parempaan huomiointiin, erityisesti liikenneonnettomuuksissa loukkaantuneiden tautitaakan arvioiminen. Lisäksi arviossa ei tarkasteltu vesiliikennettä eikä lentoliikennettä muuten kuin lentokonemelun osalta. Liikenteen kasvihuonekaasupäästöjen ilmasto- ja terveysvaikutuksia ei tässä myöskään tarkasteltu. Tulosten perusteella voidaan arvioida, että aktiivista liikkumista lisäämällä ja moottoriliikennettä vähentämällä saavutettaisiin suuria terveyshyötyjä niin koko maan tasolla kuin myös yksittäisissä kaupungeissa.
  • Norppa, Hannu; Siivola, Kirsi; Aimonen, Kukka; Suhonen, Satu; Pesonen, Saila; Vales, Gerard; Lindberg, Hanna; Koivisto, Joonas; Savolainen, Kai; Catalán, Julia (Työterveyslaitos, 2017)
  • Mattinen, Maija; Heljo, Juhani; Savolahti, Mikko (Suomen ympäristökeskus, 2016)
    Suomen ympäristökeskuksen raportteja 35/2016
    Ilmaston lämpenemistä aiheuttavista kasvihuonekaasupäästöistä noin 80 % on peräisin energian tuotannosta ja kulutuksesta (ml. liikenne), mikä tarkoittaa, että energia- ja ilmastopolitiikka ovat tiivis kokonaisuus. Vuonna 2016 Suomessa valmisteltiin uutta energia- ja ilmastostrategiaa, johon kuuluu myös skenaarioiden valmistelu. Tässä raportissa esitetty työ tukee strategian valmistelutyötä. Raportti jakaantuu kahteen osaan: rakennuskannan energiankäytön ennustamiseen ja puun pienpolton lisäämisen tarkasteluihin. Työssä tehtiin rakennustyypeittäin perusskenaarion mukainen tarkastelu, joka jatkaa tulevaisuuteen energiatilastojen lukuja vuodesta 2015 aina vuoteen 2050. Perusskenaariolla arvioidaan jo päätettyjen ja toimeenpantujen politiikkatoimien vaikutusta tulevaisuuden kehitykseen. Rakennuskannan energiankäytön osalta tehtiin ennuste peruskehityksestä ja lisäksi matalamman talouskasvun ennuste. Energiankulutus on esitetty sekä hankitun energian tasolla että hyötyenergiana. Varsinaisten asuinrakennusten (pientalot, rivi- ja ketjutalot, asuinkerrostalot) hankitun energian määrässä on pieni laskeva trendi, mutta energiantarve pysyy oleellisesti samalla tasolla tarkasteluajanjaksolla. Aurinkolämmön kehitykselle muodostettiin maltillinen lineaariseen kasvuun perustuva ennuste. Toiseksi työssä tarkasteltiin puun pienpolton lisäämisestä aiheutuvia pienhiukkaspäästöjä ja niiden vaikutusta väestöaltistukseen. Laskentaesimerkin perusteella voidaan todeta, että myös modernien, verrattain vähäpäästöisten varaavien takkojen kasvava käyttö lisää hengitysilman pienhiukkaspitoisuuksia.
  • 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.
  • 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.