Browsing by Subject "air quality"

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  • Petäjä, Tuukka; Ovaska, Aino; Fung, Pak Lun; Poutanen, Pyry; Yli-Ojanperä, Jaakko; Suikkola, Jari; Laakso, Mikko; Mäkelä, Taneli; Niemi, Jarkko V.; Keskinen, Jorma; Järvinen, Anssi; Kuula, Joel; Kurppa, Mona; Hussein, Tareq; Tarkoma, Sasu; Kulmala, Markku; Karppinen, Ari; Manninen, Hanna E.; Timonen, Hilkka (2021)
    Poor air quality influences the quality of life in the urban environment. The regulatory observation stations provide the backbone for the city administration to monitor urban air quality. Recently a suite of cost-effective air quality sensors has emerged to provide novel insights into the spatio-temporal variability of aerosol particles and trace gases. Particularly in low concentrations these sensors might suffer from issues related e.g., to high detection limits, concentration drifts and interdependency between the observed trace gases and environmental parameters. In this study we characterize the optical particle detector used in AQT530 (Vaisala Ltd.) air quality sensor in the laboratory. We perform a measurement campaign with a network of AQT530 sensors in Helsinki, Finland in 2020-2021 and present a long-term performance evaluation of five sensors for particulate (PM10, PM2.5) and gaseous (NO2, NO, CO, O-3) components during a half-year co-location study with reference instruments at an urban traffic site. Furthermore, short-term (3-5 weeks) co-location tests were performed for 25 sensors to provide sensor-specific correction equations for the fine-tuning of selected pollutants in the sensor network. We showcase the added value of the verified network of 25 sensor units to address the spatial variability of trace gases and aerosol mass concentrations in an urban environment. The analysis assesses road and harbor traffic monitoring, local construction dust monitoring, aerosol concentrations from fireworks, impact of sub-urban small scale wood combustion and detection of long-range transport episodes on a city scale. Our analysis illustrates that the calibrated network of Vaisala AQT530 air quality sensors provide new insights into the spatio-temporal variability of air pollution within the city. This information is beneficial to, for example, optimization of road dust and construction dust emission control as well as provides data to tackle air quality problems arising from traffic exhaust and localized wood combustion emissions in the residential areas.
  • Sokhi, Ranjeet S.; Moussiopoulos, Nicolas; Baklanov, Alexander; Bartzis, John; Coll, Isabelle; Finardi, Sandro; Friedrich, Rainer; Geels, Camilla; Grönholm, Tiia; Halenka, Tomas; Ketzel, Matthias; Maragkidou, Androniki; Matthias, Volker; Moldanova, Jana; Ntziachristos, Leonidas; Schäfer, Klaus; Suppan, Peter; Tsegas, George; Carmichael, Greg; Franco, Vicente; Hanna, Steve; Jalkanen, Jukka-Pekka; Velders, Guus J. M.; Kukkonen, Jaakko (Copernicus Publ., 2022)
    Atmospheric chemistry and physics
    This review provides a community’s perspective on air quality research focusing mainly on developments over the past decade. The article provides perspectives on current and future challenges as well as research needs for selected key topics. While this paper is not an exhaustive review of all research areas in the field of air quality, we have selected key topics that we feel are important from air quality research and policy perspectives. After providing a short historical overview, this review focuses on improvements in characterizing sources and emissions of air pollution, new air quality observations and instrumentation, advances in air quality prediction and forecasting, understanding interactions of air quality with meteorology and climate, exposure and health assessment, and air quality management and policy. In conducting the review, specific objectives were (i) to address current developments that push the boundaries of air quality research forward, (ii) to highlight the emerging prominent gaps of knowledge in air quality research, and (iii) to make recommendations to guide the direction for future research within the wider community. This review also identifies areas of particular importance for air quality policy. The original concept of this review was borne at the International Conference on Air Quality 2020 (held online due to the COVID 19 restrictions during 18–26 May 2020), but the article incorporates a wider landscape of research literature within the field of air quality science. On air pollution emissions the review highlights, in particular, the need to reduce uncertainties in emissions from diffuse sources, particulate matter chemical components, shipping emissions, and the importance of considering both indoor and outdoor sources. There is a growing need to have integrated air pollution and related observations from both ground-based and remote sensing instruments, including in particular those on satellites. The research should also capitalize on the growing area of low-cost sensors, while ensuring a quality of the measurements which are regulated by guidelines. Connecting various physical scales in air quality modelling is still a continual issue, with cities being affected by air pollution gradients at local scales and by long-range transport. At the same time, one should allow for the impacts from climate change on a longer timescale. Earth system modelling offers considerable potential by providing a consistent framework for treating scales and processes, especially where there are significant feedbacks, such as those related to aerosols, chemistry, and meteorology. Assessment of exposure to air pollution should consider the impacts of both indoor and outdoor emissions, as well as application of more sophisticated, dynamic modelling approaches to predict concentrations of air pollutants in both environments. With particulate matter being one of the most important pollutants for health, research is indicating the urgent need to understand, in particular, the role of particle number and chemical components in terms of health impact, which in turn requires improved emission inventories and models for predicting high-resolution distributions of these metrics over cities. The review also examines how air pollution management needs to adapt to the abovementioned new challenges and briefly considers the implications from the COVID-19 pandemic for air quality. Finally, we provide recommendations for air quality research and support for policy.
  • Heiskanen, Ilmari (Helsingin yliopisto, 2021)
    Interest towards indoor air quality has increased for several decades from human health perspective. In order to evaluate the quality of indoor air in terms of volatile organic compound (VOC) levels, robust analytical procedures and techniques must be used for indoor air VOC measurements. Since indoor building materials are the greatest source of indoor VOC emissions, same kind of procedures must be used for analysis of emission rates from building materials and their surfaces. Theory part of this thesis reviews background of VOCs and human health, legislation and guideline values, common building materials with emissions and used sampling techniques/approaches for indoor air sampling and surface material emission rate sampling & analysis. Discussed sampling techniques include, for example, material emission test chambers, field and laboratory test emission cells, solid phase microextraction (SPME) fibre applications and Radiello passive samplers. Also new innovative approaches are discussed. Used common analysis instruments are Gas Chromatography (GC) with Mass Spectrometer (MS) or Flame Ionization Detector (FID) for VOCs and High-Performance Liquid Chromatography-Ultraviolet/Visible light detector (HPLC-UV/VIS) for carbonyl VOCs (e.g. formaldehyde) after suitable derivatization. Analytical procedures remain highly ISO 16000 standard series orientated even in recent studies. In addition, potential usage of new modern miniaturized sample collection devices SPME Arrow and In-tube extraction (ITEX) used in experimental part of this thesis are discussed as an addition to indoor air and VOC emission studies. The aim of the experimental part of this thesis was to develop calibrations for selected organic nitrogen compounds with SPME Arrow and ITEX sampling techniques and test the calibration with indoor and outdoor samples. A calibration was successfully carried out with SPME Arrow (MCM-41 sorbent), ITEX (MCM-TP sorbent) and ITEX (Polyacrylonitrile (PAN) 10 % sorbent) with permeation system combined with GC-MS for the following selected organic nitrogen compounds: triethylamine, pyridine, isobutyl amine, allylamine, trimethylamine, ethylenediamine, dipropyl amine, hexylamine, 1,3-diaminopropane, 1-methyl-imidazole, N, N-dimethylformamide, 1,2-diaminocyclohexane, 1-nitropropane and formamide. The overall quality of the calibration curves was evaluated, and the calibrations were compared in terms of linear range, relative standard deviation (RSD) % for accepted calibration levels and obtained Limits of Detection (LOD) values. Also, ways to improve the calibrations were discussed. The calibration curves were tested with real indoor and outdoor samples and quantitative, as well as semi-quantitative, results were obtained.
  • Rubio-Iglesias, José Miguel; Edovald, Triin; Grew, Robert; Kark, Timo; Kideys, Ahmet Erkan; Peltola, Taru; Volten, Hester (Frontiers Media S.A., 2020)
    Frontiers in climate 2 (2020), 600998
    Environmental Protection Agencies (EPAs) have been involved in citizen science initiatives for decades, engaging with citizens with the goal of protecting and restoring our environment. Yet the data and knowledge generated and the possibilities for engaging citizens have grown significantly in the last decades thanks to the recent developments in mobile technologies and the access to internet, resulting in a transformation of how environmental protection can be done. This perspective provides some examples on how European EPAs and their partners are currently addressing key environmental challenges and exploring new institutional approaches by bringing in citizen science data and methods. It also points out challenges that need to be addressed to fully realize the potential of citizen science as a complement to the monitoring efforts by these agencies. Finally, it presents the Interest Group on Citizen Science of the Network of the Heads of Environmental Protection Agencies (EPA Network), an informal forum where EPAs across Europe share examples and bring together strategic insights on citizen science approaches into their daily activities.
  • Oksanen, Lotta; Auvinen, Mikko; Kuula, Joel; Malmgren, Rasmus; Romantschuk, Martin; Hyvärinen, Antti; Laitinen, Sirpa; Maunula, Leena; Sanmark, Enni; Geneid, Ahmed; Sofieva, Svetlana; Salokas, Julija; Veskiväli, Helin; Sironen, Tarja; Grönholm, Tiia; Hellsten, Antti; Atanasova, Nina (John Wiley & Sons A/S, 2022)
    Indoor air
    COVID-19 has highlighted the need for indoor risk-reduction strategies. Our aim is to provide information about the virus dispersion and attempts to reduce the infection risk. Indoor transmission was studied simulating a dining situation in a restaurant. Aerosolized Phi6 viruses were detected with several methods. The aerosol dispersion was modeled by using the Large-Eddy Simulation (LES) technique. Three risk-reduction strategies were studied: (1) augmenting ventilation with air purifiers, (2) spatial partitioning with dividers, and (3) combination of 1 and 2. In all simulations infectious viruses were detected throughout the space proving the existence long-distance aerosol transmission indoors. Experimental cumulative virus numbers and LES dispersion results were qualitatively similar. The LES results were further utilized to derive the evolution of infection probability. Air purifiers augmenting the effective ventilation rate by 65% reduced the spatially averaged infection probability by 30%–32%. This relative reduction manifests with approximately 15 min lag as aerosol dispersion only gradually reaches the purifier units. Both viral findings and LES results confirm that spatial partitioning has a negligible effect on the mean infection-probability indoors, but may affect the local levels adversely. Exploitation of high-resolution LES jointly with microbiological measurements enables an informative interpretation of the experimental results and facilitates a more complete risk assessment.
  • Vira, Julius (Finnish Meteorological Institute, 2017)
    Finnish Meteorological Institute Contributions ; 130
    Atmospheric chemistry and transport models are used for a wide range of applications which include predicting dispersion of a hazardous pollutants, forecasting regional air quality, and modelling global distribution of aerosols and reactive gases. However, any such prediction is uncertain due to inaccuracies in input data, model parametrisations and lack of resolution. This thesis studies methods for integrating remote sensing and in-situ observations into atmospheric chemistry models with the aim of improving the predictions. Techniques of data assimilation, originally developed for numerical weather prediction, are evaluated for improving regional-scale predictions in two forecast experiments, one targeting the photochemical pollutants ozone (O3) and nitrogen dioxide (NO2), the other targeting sulphur dioxide (SO2). In both cases, assimilation of surface-based air quality monitoring data is found to initially improve the forecast when assessed on monitoring stations not used in assimilation. However, as the forecast length increased, the forecast converged towards the reference simulations where no data assimilation was used. The relaxation time was 6-12 hours for SO2 and NO2 and about 24 hours for O3. An alternative assimilation scheme was tested for SO2. In addition to the initial state of the forecast, the scheme adjusted the gridded emission fluxes based on the observations within the last 24 hours. The improvements due to adjustment of emissions were generally small but, where observed, the improvements persisted throughout the 48 hour forecast. The assimilation scheme was further adapted for estimating emission fluxes in volcanic eruptions. Assimilating retrievals of the Infrared Atmospheric Sounding Interferometer (IASI) instrument allowed reconstructing both the vertical and horizontal profile of SO2 emissions during the 2010 eruption of Eyjafjallaj¨okull in Iceland. As a novel feature, retrievals of plume height were assimilated in addition to the commonly used column density retrievals. The results for Eyjafjallaj¨okull show that the plume height retrievals provide a useful additional constraint in conditions where the vertical distribution would otherwise remain ambiguous. Finally, the thesis presents a rigorous description and evaluation of a numerical scheme for solving the advection equation. The scheme conserves tracer mass and non-negativity, and is therefore suitable for regional and global atmospheric chemistry models. The scheme is particularly adapted for handling discontinuous solutions; for smooth solutions, the scheme is nevertheless found to perform comparably to other state-of-art schemes used in atmospheric models.
  • 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.
  • Heibati, Behzad; Jaakkola, Maritta S.; Lajunen, Taina K.; Ducatman, Alan; Veysi, Rahmat; Karimi, Ali; Jaakkola, Jouni J. K. (BioMed Central, 2022)
    Bmc pulmonary medicine
    Background: Hospital work environment contains various biological and chemical exposures that can afect indoor air quality and have impact on respiratory health of the staf. The objective of this study was to investigate potential efects of occupational exposures on the risk of respiratory symptoms and lung function in hospital work, and to evaluate potential interaction between smoking and occupational exposures. Methods: We conducted a cross-sectional study of 228 staf members in a hospital and 228 employees of an ofce building as the reference group in Shiraz, Iran. All subjects completed a standardized ATS respiratory questionnaire and performed a spirometry test. Results: In Poisson regression, the adjusted prevalence ratios (aPR) among the hospital staf were elevated for cough (aPR 1.90, 95%CI 1.15, 3.16), phlegm production (aPR 3.21, 95%CI 1.63, 6.32), productive cough (aPR 2.83, 95%CI 1.48, 5.43), wheezing (aPR 3.18, 95%CI 1.04, 9.66), shortness of breath (aPR 1.40, 95%CI 0.93, 2.12), and chest tightness (aPR 1.73, 95%CI 0.73, 4.12). Particularly laboratory personnel experienced increased risks of most symptoms. In linear regression adjusting for confounding, there were no signifcant diferences in lung function between the hospital and ofce workers. There was an indication of synergism between hospital exposures and current smoking on FEV1/FVC% (interaction term β=−5.37, 95% CI−10.27,−0.47). Conclusions: We present signifcant relations between hospital work, especially in laboratories, and increased risks of respiratory symptoms. Smoking appears to enhance these efects considerably. Our fndings suggest that policymakers should implement evidence-based measures to prevent these occupational exposures.
  • 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.
  • Saarnio, Karri; Vestenius, Mika; Kyllönen, Katriina (Ilmatieteen laitos, 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.
  • Prank, Marje (Finnish Meteorological Institute, 2017)
    Finnish Meteorological Institute Contributions ; 128
    Atmospheric composition has strong influence on human health, ecosystems and also Earth's climate. Among the atmospheric constituents, particulate matter has been recognized as both a strong climate forcer and a significant risk factor for human health, although the health relevance of the specific aerosol characteristics, such as its chemical composition, is still debated. Clouds and aerosols also contribute the largest uncertainty to the radiative budget estimates for climate projections. Thus, reliable estimates of emissions and distributions of pollutants are necessary for assessing the future climate and air-quality related health effects. Chemistry-transport models (CTMs) are valuable tools for understanding the processes influencing the atmospheric composition. This thesis consists of a collection of developments and applications of the chemistry-transport model SILAM. SILAM's ability to reproduce the observed aerosol composition was evaluated and compared with three other commonly used CTM-s in Europe. Compared to the measurements, all models systematically underestimated dry PM10 and PM2.5 by 10-60%, depending on the model and the season of the year. For majority of the PM chemical components the relative underestimation was smaller than that, exceptions being the carbonaceous particles and mineral dust - species that suffer from relatively small amount of available oservational data. The study stressed the necessity for high-quality emissions from wild-land fires and wind-suspended dust, as well as the need for an explicit consideration of aerosol water content in model-measurement comparison. The average water content at laboratory conditions was estimated between 5 and 20% for PM2.5 and between 10 and 25% for PM10. SILAM predictions were used to assess the annual mortality attributable to short-term exposures to vegetation-fire originated PM2.5 in different regions in Europe. PM2.5 emitted from vegetation fires was found to be a relevant risk factor for public health in Europe, more than 1000 premature deaths per year were attributed to vegetation-fire released PM2.5. CTM predictions critically depend on emission data quality. An error was found in the EMEP anthropogenic emission inventory regarding the SOx and PM missions of metallurgy plants on the Kola Peninsula and SILAM was applied to estimate the accuracy of the proposed correction. Allergenic pollen is arguably the type of aerosol with most widely recognised effect to health. SILAM's ability to predict allergenic pollen was extended to include Ambrosia Artemisiifolia - an invasive weed spreading in Southern Europe, with extremely allergenic pollen capable of inducing rhinoconjuctivitis and asthma in the sensitive individuals even in very low concentrations. The model compares well with the pollen observations and predicts occasional exceedances of allergy relevant thresholds even in areas far from the plants' habitat. The variations of allergenicity in grass pollen were studied and mapped to the source areas by adjoint computations with SILAM. Due to the high year-to-year variability of the observed pollen potency between the studied years and the sparse observational network, no clear geographic pattern of pollen allergenicity was detected.
  • Fung, Pak Lun; Sillanpää, Salla; Niemi, Jarkko V.; Kousa, Anu; Timonen, Hilkka; Zaidan, Martha Arbayani; Saukko, Erkka; Kulmala, Markku; Petäjä, Tuukka; Hussein, Tareq (Elsevier, 2022)
    Science of the total environment
    To convey the severity of ambient air pollution level to the public, air quality index (AQI) is used as a communication tool to reflect the concentrations of individual pollutants on a common scale. However, due to the enhanced air pollution control in recent years, air quality has improved, and the roles of some air pollutant species included in the existing AQI as urban air pollutants have diminished. In this study, we suggest the current AQI should be revised in a way that new air pollution indicators would be considered so that it would better represent the health effects caused by local combustion processes from traffic and residential burning. Based on the air quality data of 2017–2019 in three different sites in Helsinki metropolitan area, we assumed the statistical distributions of the current indicators (NO2 and PM2.5) and the proposed particulate indicators (BC, LDSA and PNC) were related as they have similar sources in urban regions despite the varying correlations between the current and proposed indicators (NO2: r = 0.5–0.85, PM2.5: r = 0.28–0.72). By fitting the data to an optimal distribution function, together with expert opinions, we improved the current Finnish AQI and determined the AQI breakpoints for the proposed indicators where this robust statistical approach is transferrable to other cities. The addition of the three proposed indicators to the current AQI would decrease the number of good air quality hours in all three environments (largest decrease in urban traffic site, ~22 %). The deterioration of air quality class appeared more severe during peak hours in the urban traffic site due to vehicular emission and evenings in the detached housing site where domestic wood combustion often takes place. The introduction of the AQI breakpoints of the three new indicators serve as a first step of improving the current AQI before further air quality guideline levels are updated.
  • Le, Viet (Ilmansuojeluyhdistys ry., 2022)
  • Fung, Pak Lun; Zaidan, Martha; Sillanpää, Salla; Kousa, Anu; Niemi, Jarkko V.; Timonen, Hilkka; Kuula, Joel; Saukko, Erkka; Luoma, Krista Hannele; Petäjä, Tuukka; Tarkoma, Sasu; Kulmala, Markku; Hussein, Tareq (2020)
    Missing data has been a challenge in air quality measurement. In this study, we develop an input-adaptive proxy, which selects input variables of other air quality variables based on their correlation coefficients with the output variable. The proxy uses ordinary least squares regression model with robust optimization and limits the input variables to a maximum of three to avoid overfitting. The adaptive proxy learns from the data set and generates the best model evaluated by adjusted coefficient of determination (adjR2). In case of missing data in the input variables, the proposed adaptive proxy then uses the second-best model until all the missing data gaps are filled up. We estimated black carbon (BC) concentration by using the input-adaptive proxy in two sites in Helsinki, which respectively represent street canyon and urban background scenario, as a case study. Accumulation mode, traffic counts, nitrogen dioxide and lung deposited surface area are found as input variables in models with the top rank. In contrast to traditional proxy, which gives 20–80% of data, the input-adaptive proxy manages to give full continuous BC estimation. The newly developed adaptive proxy also gives generally accurate BC (street canyon: adjR2 = 0.86–0.94; urban background: adjR2 = 0.74–0.91) depending on different seasons and day of the week. Due to its flexibility and reliability, the adaptive proxy can be further extend to estimate other air quality parameters. It can also act as an air quality virtual sensor in support with on-site measurements in the future.
  • Sillanpää, Salla; Fung, P.L; Niemi, J.V.; Kousa, A; Kangas, L; Zaidan, M.A.; Timonen, H; Kulmala, M.; Petäjä, T; Hussein, T (Finnish Environment Institute, 2022)
    Boreal environment research
    Long-term trends of ambient gaseous pollutants and particulate matter in Helsinki metropolitan area were analyzed from 1994 to 2019. Measurement data from ten monitoring stations located in different types of urban environments including traffic, urban background, rural background, and suburban area were included in this study. We analyzed gas-phase air pollutants, such as NO, NO2, NOx, O3, SO2 and CO; and for aerosol pollutants, we explored mass concentrations for particles smaller than 10 µm and 2.5 µm in diameter (PM10 and PM2.5, respectively ). In order to quantify trends in the data, we deployed a non-parametric Mann-Kendall test and Theil-Sen method. The results were compared with the regional emissions trends and changes in meteorological conditions. Our analysis indicates that SO2 and CO in all stations have decreased to values corresponding to their regional background concentration levels and their role as urban air pollutants have diminished. Our results from the Helsinki Metropolitan area during the last 25 years show that the air quality improved and all the air pollutant concentrations show a decreasing trend, except ozone. Based on our analysis of the Air Quality Index (AQI) at traffic and urban background environments, NO2 concentration, which have typically represented the health effects resulting from vehicular traffic, is rapidly decreasing also in traffic environments. The current AQI standard therefore lacks clarity on the potential health risks from other air pollutants emitted from traffic exhaust. In addition, the air quality indicators currently considered in the AQI do not represent well enough residential wood burning and the possible health outcomes from its exposure. We suggest that the current AQI should be revised in a way that new air quality parameters would be considered, which would better represent the health effects resulting from these local combustion sources.
  • Foreback, Benjamin; Dada, Lubna; Daellenbach, Kaspar R.; Yan, Chao; Wang, Lili; Chu, Biwu; Zhou, Ying; Kokkonen, Tom V.; Kurppa, Mona; Pileci, Rosaria E.; Wang, Yonghong; Chan, Tommy; Kangasluoma, Juha; Zhuohui, Lin; Guo, Yishou; Li, Chang; Baalbaki, Rima; Kujansuu, Joni; Fan, Xiaolong; Feng, Zemin; Rantala, Pekka; Gani, Shahzad; Bianchi, Federico; Kerminen, Veli-Matti; Petäjä, Tuukka; Kulmala, Markku; Liu, Yongchun; Paasonen, Pauli (Copernicus Publ., 2022)
    Atmospheric chemistry and physics
    This study investigates the influence of the Chinese New Year (CNY) celebrations on local air quality in Beijing from 2013 through 2019. CNY celebrations include burning of fireworks and firecrackers, which consequently has a significant short-term impact on local air quality. In this study, we bring together comprehensive observations at the newly constructed Aerosol and Haze Laboratory at Beijing University of Chemical Technology – West Campus (BUCT-AHL) and hourly measurements from 12 Chinese government air quality measurement stations throughout the Beijing metropolitan area. These datasets are used together to provide a detailed analysis of air quality during the CNY over multiple years, during which the city of Beijing prohibited the use of fireworks and firecrackers in an effort to reduce air pollution before CNY 2018. Datasets used in this study include particulate matter mass concentrations (PM2.5 and PM10), trace gases (NOx , SO2, O3, and CO), and meteorological variables for 2013–2019; aerosol particle size distributions; and concentrations of sulfuric acid and black carbon for 2018 and 2019. Studying the CNY over several years, which has rarely been done in previous studies, can show trends and effects of societal and policy changes over time, and the results can be applied to study problems and potential solutions of air pollution resulting from holiday celebrations. Our results show that during the 2018 CNY, air pollutant concentrations peaked during the CNY night (for example, PM2.5 reached a peak around midnight of over 250 µg cm−3 , compared to values of less than 50 µg cm−3 earlier in the day). The pollutants with the most notable spikes were sulfur dioxide, particulate matter, and black carbon, which are emitted in burning of fireworks and firecrackers. Sulfuric acid concentration followed the sulfur dioxide concentration and showed elevated overnight concentration. Analysis of aerosol particle number size distribution showed direct emissions of particles with diameters around 100 nm in relation to firework burning. During the 2019 CNY, the pollution levels were somewhat lower (PM2.5 peaking at around 150 µg cm−3 on CNY compared to values around 100 µg cm−3 earlier in the day), and only minor peaks related to firework burning were observed. During both CNYs 2018 and 2019 secondary aerosol formation in terms of particle growth was observed. Meteorological conditions were comparable between these 2 years, suggesting that CNY-related emissions were less in 2019 compared to 2018. During the 7-year study period, it appears that there has been a general decrease in CNY-related emissions since 2016. For example, the peak in PM2.5 in 2016 was over 600 µg cm−3, and in the years following, the peak was less each year, with a peak around 150 µg cm−3 in 2019. This is indicative of the restrictions and public awareness of the air quality issues having a positive effect on improving air quality during the CNY. Going into the future, long-term observations will offer confirmation for these trends.
  • Karl, Matthias; Pirjola, Liisa; Karppinen, Ari; Jalkanen, Jukka-Pekka; Ramacher, Martin Otto Paul; Kukkonen, Jaakko (2020)
    Marine traffic in harbors can be responsible for significant atmospheric concentrations of ultrafine particles (UFPs), which have widely recognized negative effects on human health. It is therefore essential to model and measure the time evolution of the number size distributions and chemical composition of UFPs in ship exhaust to assess the resulting exposure in the vicinity of shipping routes. In this study, a sequential modelling chain was developed and applied, in combination with the data measured and collected in major harbor areas in the cities of Helsinki and Turku in Finland, during winter and summer in 2010-2011. The models described ship emissions, atmospheric dispersion, and aerosol dynamics, complemented with a time-microenvironment-activity model to estimate the short-term UFP exposure. We estimated the dilution ratio during the initial fast expansion of the exhaust plume to be approximately equal to eight. This dispersion regime resulted in a fully formed nucleation mode (denoted as Nuc(2)). Different selected modelling assumptions about the chemical composition of Nuc(2) did not have an effect on the formation of nucleation mode particles. Aerosol model simulations of the dispersing ship plume also revealed a partially formed nucleation mode (Nuc(1); peaking at 1.5 nm), consisting of freshly nucleated sulfate particles and condensed organics that were produced within the first few seconds. However, subsequent growth of the new particles was limited, due to efficient scavenging by the larger particles originating from the ship exhaust. The transport of UFPs downwind of the ship track increased the hourly mean UFP concentrations in the neighboring residential areas by a factor of two or more up to a distance of 3600 m, compared with the corresponding UFP concentrations in the urban background. The substantially increased UFP concentrations due to ship traffic significantly affected the daily mean exposures in residential areas located in the vicinity of the harbors.
  • Kuula, Joel; Timonen, Hilkka; Niemi, Jarkko V.; Manninen, Hanna E.; Rönkkö, Topi; Hussein, Tareq; Fung, Pak Lun; Tarkoma, Sasu; Laakso, Mikko; Saukko, Erkka; Ovaska, Aino; Kulmala, Markku; Karppinen, Ari; Johansson, Lasse; Petäjä, Tuukka (Copernicus GmbH, 2022)
    Atmospheric Chemistry and Physics
    As evidence of adverse health effects due to air pollution continues to increase, the World Health Organization (WHO) recently published its latest edition of the global air quality guidelines (World Health Organization, 2021). Although not legally binding, the guidelines aim to provide a framework in which policymakers can combat air pollution by formulating evidence-based air quality management strategies. In the light of this, the European Union has stated its intent to revise the current ambient air quality directive (2008/50/EC) to more closely resemble the newly published WHO guidelines (European Commission, 2020). This article provides an informed opinion on selected features of the air quality directive that we believe would benefit from a reassessment. The selected features include discussion about (1) air quality sensors as a part of a hierarchical observation network, (2) the number of minimum sampling points and their siting criteria, and (3) new target air pollution parameters for future consideration.
  • Kuula, Joel (2020)
    Finnish Meteorological Institute Contributions ; 170
    Atmospheric particles are one of the leading mortality risk factors in the Global Burden of Disease study (GBD). The association between particulate mass of particles smaller than 2.5 μm in diameter (PM2.5) and cardiovascular and pulmonary diseases has been characterized by multiple epidemiological studies, and varying estimates suggest that several million premature death occur globally each year due to PM2.5 exposure. Mitigation of the adverse health effects of particulate matter requires comprehensive understanding of their sources and dynamic processes, such as spatial dispersion. Recent emergence and development of aerosol sensors, which are typically characterized as small, relatively low cost and easy to use, have enabled new opportunities in air quality monitoring. As a result of their practical convenience, sensors can be deployed to the field in high quantities which, consequently, enables network-type, spatially comprehensive measurements. However, with more simplified and less expensive measurement approach, less accurate and reliable results may be expected. This study aimed to evaluate and characterize the accuracy and usability of aerosol sensor to urban air quality measurements. The investigation focused on two of the most prominent measurement techniques applicable to sensor type monitoring; optical and diffusion chargingbased techniques. Sensors utilizing optical technique were evaluated in laboratory and field studies for their error sources and particle size-selectivity, specifically. Diffusion charging-based sensors, which measure lung deposited surface area of particles, were evaluated in the field for their suitability to measure combustion emitted particles, such as vehicular exhaust and residential wood combustion emissions. Results of the study indicated that optical aerosol sensors are unlikely to be fit for long-term regulatory monitoring. The main issues preventing this arise from their improper calibration which poses a significant risk of data misinterpretation; none of the laboratory evaluated sensors measured particle sizes which their technical specifications implied. On the other hand, field tests showed that when the measured size fraction was targeted to match the true detection range of the sensor, highly accurate and repeatable results were obtained. This implies that, while the usability of optical sensors is limited in their current form, the concept and vision of a sensor driven air quality monitoring network remains valid and achievable. In comparison to optical sensors, diffusion charging-based sensors were found to be more mature in terms of their technological development. The evaluated sensors exhibited accurate and stable performance throughout the test campaigns and were shown to be particularly well-suited the measurement of combustion emitted particles. Hence, diffusion charger sensors would be a valuable addition to be used alongside other measurement techniques as urban air quality is heavily affected by nanoparticles. *** Ilmakehän pienhiukkaset ovat yksi keskeisimmistä kuolleisuuden riskitekijöistä kansainvälisessä taudin rasittavuuden analyysissä. Useat epidemiologiset tutkimukset ovat osoittaneet pienhiukkasten ja sydän- ja verisuoni- sekä hengitystiesairauksien yhteyden, ja eri arvioiden mukaan useita miljoonia ennenaikaisia kuolemia tapahtuu joka vuosi pienhiukkasaltistumisen seurauksena. Jotta pienhiukkasten negatiivisiin terveysvaikutuksiin voitaisiin vaikuttaa, tulee niiden lähteet ja dynaamiset prosessit, kuten alueellinen leviäminen, tuntea hyvin. Viimeaikainen aerosolisensoreiden esilletulo ja kehittyminen ovat avanneet uusia mahdollisuuksia ilmanlaadun seurantaan. Sensorit, jotka ovat tyypillisesti pienikokoisia, suhteellisen edullisia ja helppokäyttöisiä, mahdollistavat alueellisesti kattavien sensoriverkkomittausten toteuttamisen ja siten pienhiukkasten tarkemman tutkimisen. Sensoreiden edullisempi ja siten yksinkertaisempi mittaustekniikka saattaa toisaalta johtaa suurempaan mittausepätarkkuuteen ja huonompaan laatuun. Tämän työn tavoitteena oli arvioida ja luonnehtia aerosolisensoreiden tarkkuutta ja soveltuvuutta kaupunkialueiden ilmanlaadun seurantaan. Tutkimus keskittyi kahteen mittaustekniikkaan, jotka ovat parhaiten sovellettavissa sensorityyppisiin mittauksiin; optiseen ja diffuusiovarautumiseen perustuvaan tekniikkaan. Optisia sensoreita testattiin sekä ulkoilmassa että laboratoriossa, missä niiden hiukkaskokovalikoivuutta arvioitiin tutkimalla sensorin vastetta keinotekoisesti tuotetuilla erikokoisilla referenssihiukkasilla. Diffuusiovarautumiseen perustuvia sensoreita, jotka mittaavat niin kutsuttua keuhkodeposoituvaa pinta-ala, testattiin ulkoilmassa, missä niiden suorituskykyä arvioitiin erityisesti erittäin pienten nanohiukkasten, kuten liikenteen pakokaasun sekä puunpolton päästöjen, näkökulmasta. Tutkimustulosten perusteella optiset aerosolisensorit eivät toistaiseksi ole soveltuvia pitkäaikaiseen viranomaisvalvonnassa tehtävään ilmanlaadun seurantaan. Tämä johtuu niiden virheellisestä kalibroinnista, jonka seurauksena sensorit eivät mittaa hiukkaskokoluokkia, joita niiden tekniset tuoteselosteet antavat olettaa. Riski mittausdatan väärin tulkinnalle on täten ilmeinen. Toisaalta, kun mitattu hiukkasten kokojakauma rajattiin vastaamaan sensorin ominaista vastealuetta, sensorin mittaustarkkuus oli hyvä ja toistettava. Tämän perusteella, vaikkakin virheellinen kalibrointi rajoittaa optisten sensoreiden käytettävyyttä, konsepti ja visio sensoripohjaisesta mittausverkosta on mahdollinen ja saavutettavissa. Diffuusiovarautumiseen perustuvat sensorit osoittivat olevan teknisesti kehittyneempiä kuin optiset sensorit. Testatut sensorit olivat tarkkoja ja stabiileja kaikissa kenttämittauskampanjoissa, ja ne olivat erityisen hyvin soveltuvia liikenteen pakokaasujen sekä puunpolton päästöjen mittaamiseen. Tämän vuoksi diffuusiovaraukseen perustuvat sensorit olisivat arvokas lisä muiden mittaustekniikoiden rinnalle, varsinkin kun nanohiukkasten osuus kaupunki-ilmassa on merkittävä.
  • Fink, Lea; Karl, Matthias; Matthias, Volker; Oppo, Sonia; Kranenburg, Richard; Kuenen, Jeroen; Moldanova, Jana; Jutterström, Sara; Jalkanen, Jukka-Pekka; Majamäki, Elisa (Copernicus Publ., 2023)
    Atmospheric chemistry and physics
    Shipping has a significant share in the emissions of air pollutants such as NOx and particulate matter (PM), and the global maritime transport volumes are projected to increase further in the future. The major route for short sea shipping within Europe and the main shipping route between Europe and East Asia are found in the Mediterranean Sea. Thus, it is a highly frequented shipping area, and high levels of air pollutants with significant potential impacts from shipping emissions are observed at monitoring stations in many cities along the Mediterranean coast. The present study is part of the EU H2020 project SCIPPER (Shipping contribution to Inland Pollution Push for the Enforcement of Regulations). Five different regional chemistry transport models (CAMx – Comprehensive Air Quality Model with Extensions, CHIMERE, CMAQ, EMEP – European Monitoring and Evaluation Programme, LOTOS-EUROS) were used to simulate the transport, chemical transformation and fate of atmospheric pollutants in the Mediterranean Sea for 2015. Shipping emissions were calculated with the Ship Traffic Emission Assessment Model (STEAM) version 3.3.0, and land-based emissions were taken from the CAMS-REG v2.2.1 dataset for a domain covering the Mediterranean Sea at a resolution of 12 km 12 km (or 0.1deg by 0.1 deg). All models used their standard setup for further input. The potential impact of ships was calculated with the zero-out method. The model results were compared to each other and to measured background data at monitoring stations. The model results differ regarding the time series and pattern but are similar concerning the overall underestimation of NO2 and overestimation of O3. The potential impact from ships on the total NO2 concentration was especially high on the main shipping routes and in coastal regions (25% to 85 %). The potential impact from ships on the total O3 concentration was lowest in regions with the highest NO2 impact (down to 20%). CAMx and CHIMERE simulated the highest potential impacts of ships on the NO2 and O3 air concentrations. Additionally, the strongest correlation was found between CAMx and CHIMERE, which can be traced back to the use of the same meteorological input data. The other models used different meteorological input due to their standard setup. The CMAQ-, EMEP- and LOTOS-EUROS-simulated values were within one range for the NO2 and O3 air concentrations. Regarding simulated deposition, larger differences between the models were found when compared to air concentration. These uncertainties and deviations between models are caused by deposition mechanisms, which are unique within each model. A reliable output from models simulating ships’ potential impacts can be expected for air concentrations of NO2 and O3.