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21.
Detection of particle-phase polycyclic aromatic hydrocarbons in Mexico City using an aerosol mass spectrometer
Katja Džepina, Janet Arey, Linsey C. Marr, D. Worsnop, Dara Salcedo, Q. Zhang, Timothy B. Onasch, Luisa T. Molina, Mario J. Molina, Jose L. Jimenez, 2007, izvirni znanstveni članek

Opis: We report the quantification of ambient particle-bound polycyclic aromatic hydrocarbons (PAHs) for the first time using a real-time aerosol mass spectrometer. These measurements were carried out during the Mexico City Metropolitan Area field study (MCMA-2003) that took place from March 29 to May 4, 2003. This was the first time that two different fast, real-time methods have been used to quantify PAHs alongside traditional filter-based measurements in an extended field campaign. This paper focuses on the technical aspects of PAH detection in ambient air with the Aerodyne AMS equipped with a quadrupole mass analyzer (Q-AMS), on the comparison of PAHs measured by the Q-AMS to those measured with the other two techniques, and on some features of the ambient results. PAHs are very resistant to fragmentation after ionization. Based on laboratory experiments with eight PAH standards, we show that their molecular ions, which for most particulate PAHs in ambient particles are larger than 200 amu, are often the largest peak in their Q-AMS spectra. Q-AMS spectra of PAH are similar to those in the NIST database, albeit with more fragmentation. We have developed a subtraction method that allows the removal of the contribution from non-PAH organics to the ion signals of the PAHs in ambient data. We report the mass concentrations of all individual groups of PAHs with molecular weights of 202, 216, 226 + 228, 240 + 242, 250 + 252, 264 + 266, 276 + 278, 288 + 290, 300 + 302, 316 and 326 + 328, as well as their sum as the total PAH mass concentration. The time series of the Photoelectric Aerosol Sensor (PAS) and Q-AMS PAH measurements during MCMA-2003 are well correlated, with the smallest difference between measured PAH concentrations observed in the mornings when ambient aerosols loadings are dominated by fresh traffic emissions. The Q-AMS PAH measurements are also compared to those from GC–MS analysis of filter samples. Several groups of PAHs show agreement within the uncertainties, while the Q-AMS measurements are larger than the GC–MS ones for several others. In the ambient Q-AMS measurements the presence of ions tentatively attributed to cyclopenta[cd]pyrene and dicyclopentapyrenes causes signals at m/z 226 and 250, which are significantly stronger than the signals in GC–MS analysis of filter samples. This suggests that very labile, but likely toxic, PAHs were present in the MCMA atmosphere that decayed rapidly due to reaction during filter sampling, and this may explain at least some of the differences between the Q-AMS and GC–MS measurements.
Najdeno v: osebi
Ključne besede: AMS, PAH, Mexico City
Objavljeno: 11.04.2021; Ogledov: 864; Prenosov: 0
.pdf Polno besedilo (4,12 MB)

22.
Comparative Analysis of urban atmospheric aerosol by particle-induced X-ray emission (PIXE), proton elastic scattering analysis (PESA), and aerosol mass spectrometry (AMS)
Katja Džepina, Mario J. Molina, V. Shutthanandan, Luisa T. Molina, Dara Salcedo, K.S. Johnson, A. Laskin, Jose L. Jimenez, 2008, izvirni znanstveni članek

Opis: A multifaceted approach to atmospheric aerosol analysis is often desirable infield studies where an understanding of technical comparability among different measurement techniques is essential. Herein, we report quantitative intercomparisons of particle-induced X-ray emission (PIXE) and proton elastic scattering analysis (PESA), performed offline under a vacuum, with analysis by aerosol mass spectrometry (AMS) carried out in real-time during the MCMA-2003 Field Campaign in the Mexico City Metropolitan Area. Good agreement was observed for mass concentrations of PIXE-measured sulfur (assuming it was dominated by SO42-) and AMS-measured sulfate during most of the campaign. PESA-measured hydrogen mass was separated into sulfate H and organic H mass fractions, assuming the only major contributions were (NH4)(2)SO4 and organic compounds. Comparison of the organic H mass with AMS organic aerosol measurements indicates that about 75% of the mass of these species evaporated under a vacuum. However similar to 25% of the organics does remain under a vacuum, which is only possible with low-vapor-pressure compounds, and which supports the presence of high-molecular-weight or highly oxidized organics consistent with atmospheric aging. Approximately 10% of the chloride detected by AMS was measured by PIXE, possibly in the form of metal-chloride complexes, while the majority of Cl was likely present as more volatile species including NH4Cl. This is the first comparison of PIXE/PESA and AMS and, to our knowledge, also the first report of PESA hydrogen measurements for urban organic aerosols.
Najdeno v: osebi
Ključne besede: organic aerosols, secondary organic aerosols, Mexico City, MCMA-2003 field campaign
Objavljeno: 11.04.2021; Ogledov: 835; Prenosov: 0
.pdf Polno besedilo (1,74 MB)

23.
WRF-Chem simulations of Saharan dust outbreak episode at North Adriatic coast
Katja Džepina, 2018, prispevek na konferenci brez natisa

Najdeno v: osebi
Ključne besede: Atmospheric aerosol, Sahara dust, WRF-Chem, Northern Adriatic
Objavljeno: 28.05.2021; Ogledov: 752; Prenosov: 0
.pdf Polno besedilo (24,83 MB)

24.
Utjecaj atmosferskih lebdećih čestica na ljudsko zdravlje
Katja Džepina, 2018, objavljeni povzetek znanstvenega prispevka na konferenci (vabljeno predavanje)

Opis: Kvalitetu zraka u današnjem svijetu određuju ljudske aktivnosti iz kojih nastaje antropogeno zagađenje zraka. Utjecaj antropogenog zagađenja na kvalitetu zraka snažno se povećao od početka industrijske revolucije prije cc 150 godina. Na globalnom nivou, smanjenje kvalitete zraka u svijetu nakon pre-industrijskih vremena nepobitno uzrokuje zagrijavanje planeta Zemlje zbog ljudskih aktivnosti, kako je nedavno objavljeno i u izvještaju Međunarodnog panela za promjenu klime (eng. Intergovernmental Panel for Climate Change, IPCC). Ljudi posebno izloženi lošoj kvaliteti zraka su oni koji žive u područjima gdje standardi kvalitete zraka ne postoje ili se ne sprovode, poput ljudi koji žive pored izvora zagađenja ili u društvima koja se razvijaju. Tijekom zime 2017. - 2018. u periodu kada se po dostupnim podacima događaju epizode najgore kvalitete zraka u Kantonu Sarajevo (4. decembar 2017. – 15. mart 2018.) u Kantonu Sarajevo odvila su se terenska mjerenja sastojaka atmosfere u sklopu kampanje SAFICA 2017-2018 (“Sarajevo Canton Winter Field Campaign 2017-2018“). SAFICA projekt vodili su Federalni hidrometeorološki zavod BiH, Zavoda za javno zdravstvo Kantona Sarajeva, Univerzitet u Sarajevu i Sveučilište u Rijeci, a mjerenja su se odvijala na tri urbane lokacije unutar grada Sarajeva (Otoka, Pofalići i Bjelave) i jednoj pozadinskoj (planinski prijevoj Ivan Sedlo). U ovom predavanju, objasnit će se osnove antropogenog zagađenja zraka i njegovog globalnog utjecaja na kvalitetu zraka, i dati primjeri različitih kvaliteta zraka u modernim društvima kao i u onima koja se tek razvijaju. Posebna pažnja bit će posvećena atmosferskim lebdećim česticama i objasnit će se njihov nastanak i važnost parametara čestica poput atmosferske koncentracije, veličine i kemijskog sastava. Također, dat će se prikaz negativnog utjecaja čestica na ljudsko zdravlje i objasniti zašto su atmosferske koncentracije sitnih atmosferskih čestica linearno korelirane sa smrtnošću ljudi. Konačno, predstavit će se preliminarni rezultati mjerenja sastojaka atmosfere u kantonu Sarajevo tijekom SAFICA kampanje i usporedit sa rezultatima iz drugih svjetskih urbanih područja.
Najdeno v: osebi
Ključne besede: Atmosferske lebdeće čestice, Antropogeno zagađenje zraka, Sarajevo, Bosna i Hercegovina, SAFICA 2018
Objavljeno: 27.05.2021; Ogledov: 776; Prenosov: 0
.pdf Polno besedilo (9,29 MB)

25.
Utjecaj atmosferskih lebdećih čestica na ljudsko zdravlje
Katja Džepina, 2018, vabljeno predavanje na konferenci brez natisa

Najdeno v: osebi
Objavljeno: 29.05.2021; Ogledov: 662; Prenosov: 0
.pdf Polno besedilo (1,13 MB)

26.
Chemical characterization of atmospheric aerosols in the Sarajevo Canton
Katja Džepina, 2018, objavljeni povzetek znanstvenega prispevka na konferenci (vabljeno predavanje)

Opis: The World Health Organization (WHO) identified air pollution as the world’s largest single environmental health risk causing seven million deaths per year, one in eight deaths globally. Of particular concern are heavily polluted and understudied urban centres: while thousands of scientific papers have been published on air quality of the cities such as London, UK and Los Angeles, USA, only 41 papers exist on the top 10 globally most polluted cities. Sarajevo, the capital of Bosnia and Herzegovina (B&H), is one of urban centres which often experiences low air quality due to the extensive use of non-renewable energy sources and geographical location. For example, in Sarajevo during 2010, an annual average concentration of particulate matter (PM) with a diameter smaller than 10 µm (PM10) was 50 µg/m3, a value 2.5x higer than the recommended WHO guidelines value of 20 µg/m3. Sarajevo Canton Winter Field Campaign 2017-2018 (SAFICA) took place in the Sarajevo Canton during the cold winter season of 2017 – 2018 (Dec 4, 2017 – Mar 15, 2018), the period historically characterized with the lowest air quality according to the available data. SAFICA project was lead by Federal hydrometeorological Institute of B&H, Institute of Public Health of the Sarajevo Canton, University of Sarajevo and University of Rijeka, and field measurements took place at three urban locations within the city of Sarajevo (Otoka, Pofalići i Bjelave) i one remote location (Ivan Sedlo mountain ridge). In this presentation, the basics of anthropogenic air pollution and its global influece on the air quality will be explained. Particular attention will be given to the atmospheric PM or aerosols, and aerosols formation mechanisms and the importance of their characteristics such as atmospheric concentration, size and chemical composition will be explained. Also, the reasons for the adverse effects of aerosols on human health and the correlation of atmospheric fine PM (PM2.5) concentrations and human mortality will be explained. Finally, preliminary results of SAFICA measurements campaign will be presented and compared with those from other global urban centers.
Najdeno v: osebi
Ključne besede: atmospheric aerosol, Sarajevo, urban air pollution, SAFICA 2018
Objavljeno: 26.05.2021; Ogledov: 803; Prenosov: 0
.pdf Polno besedilo (6,65 MB)

27.
Analiza utjecaja zagađenja zraka na zdravlje ljudi u Bosni i Hercegovini
Katja Džepina, 2018, prispevek na konferenci brez natisa

Najdeno v: osebi
Ključne besede: PM2.5, Ozone, Sarajevo, Tuzla, Zenica, Bosnia and Herzegovina, US EPA BenMAP, Cost-Benefit Analysis, Adverse health effects
Objavljeno: 29.05.2021; Ogledov: 810; Prenosov: 0
.pdf Polno besedilo (644,83 KB)
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28.
Molekularna karakterizacija lebdećih čestica slobodne troposfere sa Opservatorija Pico planine
Sumit Kumar, J. A. Perlinger, D. Helmig, J. Hueber, Swarup China, B. Zhang, R. Chris Owen, Katja Džepina, Claudio Mazzoleni, Paulo Fialho, 2017, objavljeni povzetek znanstvenega prispevka na konferenci

Opis: Long-range transported free tropospheric aerosol was sampled at the PMO (38°28’15’’N, 28°24’14’’W; 2225 m amsl) on Pico Island of the Azores in the North Atlantic. Filter-collected aerosol during summer 2012 was analysed for organic and elemental carbon, and inorganic ions. The average aerosol ambient concentration was 0.9 µg m-3. Organic aerosol contributed the majority of mass (57%), followed by sulphate (21%) and nitrate (17%). Filter-collected aerosol was positively correlated with on-line aerosol measurements of black carbon, light scattering and number concentration. Water-soluble organic compounds (WSOC) from 9/24 and 9/25 samples collected during a pollution event were analysed with ultrahigh-resolution FT-ICR MS. FLEXPART analysis showed the air masses were very aged (>12 days). ~4000 molecular formulas were assigned to each of the mass spectra between m/z 100-1000. The majority of the assigned molecular formulas have unsaturated structures with CHO and CHNO elemental compositions. WSOC have an average O/C of ~0.45, relatively low compared to O/C of other aged aerosol, which might be the result of evaporation and fragmentation during long-range transport. The increase in aerosol loading during 9/24 was linked to biomass burning emissions from North America by FLEXPART and MODIS fire counts. This was confirmed with WSOC biomass burning markers and with the morphology and mixing state of particles as determined by SEM. The presence of markers characteristic of aqueous-phase reactions of biomass burning phenolic species suggests that the aerosol collected at Pico had undergone cloud processing. The air masses on 9/25 were more aged (~15 days) and influenced by marine emissions, as indicated by organosulphates and species characteristic for marine aerosol (e.g. fatty acids). The change in air masses for the two samples was corroborated by the changes in ozone, ethane, propane, morphology of particles, as well as by FLEXPART. In this presentation we will presents the first detailed molecular characterization of free tropospheric aged aerosol intercepted at the PMO.
Najdeno v: osebi
Ključne besede: Atmospheric aerosol, Free troposphere, Mass spectrometry, Pico mountain observatory
Objavljeno: 26.05.2021; Ogledov: 741; Prenosov: 0
.pdf Polno besedilo (8,36 MB)

29.
Sarajevo Canton Winter Field Campaign 2018
Griša Močnik, Jasna Huremović, Sabina Žero, Roberto Casotto, Athanasia Vlachou, Anna Tobler, Francesco Canonaco, Deepika Bhattu, Katja Džepina, Vaios Moschos, 2020, objavljeni povzetek znanstvenega prispevka na konferenci

Opis: Nowadays, urban centres in countries of the Western Balkan region (including Bosnia and Herzegovina (B&H)) are experiencing some of the poorest European and global air quality due to the extensive use of solid fuels (e.g., wood, coal) and old vehicle fleet. Western Balkan countries lack state-of-the-art atmospheric sciences research despite high levels of ambient pollution, which makes the efforts to understand the mechanisms of their air pollution imperative. The city of Sarajevo, the capital of B&H, is situated in a basin surrounded by mountains. Particularly during the winter months, topography and meteorology cause significant pollution episodes. The Sarajevo Canton Winter Field Campaign 2018 (SAFICA) took place from Dec 04, 2017 to Mar 15, 2018 with on-line aerosol measurements and collection of daily, continuous filter PM10 samples for off-line laboratory analyses. SAFICA aimed to give the first detailed characterization of the Western Balkans aerosol composition including organic aerosol (OA) to elucidate aerosol emission sources and atmospheric processing and to estimate the adverse health effects. PM10 samples (ntotal=180) were collected at four sites in the Sarajevo Canton: a) Bjelave and b) Pofalići (urban background); c) Otoka (urban); d) Ivan Sedlo (remote). The urban sites were distributed along the city basin to study the pollutants’ urban evolution and the remote site was chosen to compare urban to background air masses. SAFICA PM10 samples underwent different off-line laboratory chemical analyses: 1) Bulk chemical composition of the total filter-collected water-soluble inorganic and OA by a high-resolution Aerodyne Aerosol Mass Spectrometer (AMS). The measured AMS OA spectra were further analysed by Positive Matrix Factorization (PMF) using the graphical user interface SoFi (Source Finder) to separate OA into subtypes characteristic for OA sources and atmospheric processes. 2) Organic and elemental carbon (OC/EC), water-soluble organic carbon, polycyclic aromatic hydrocarbons, levoglucosan, and 14C content of total carbon to evaluate OA chemical composition. 3) Major inorganic anions and cations to evaluate aerosol inorganic species. 4) Metal content in aerosol determined by two analytical techniques (AAS and ICP-MS). SAFICA on-line measurements of black carbon (Aethalometer) and the particle number concentration (Condensation Particle Counter and Optical Particle Sizer) enabled the insights into the daily evolution of primary pollutants and an assessment of aerosol size and number distribution. The combined SAFICA results for on- and off-line measurements will be presented. Our results show that the carbon-containing species make ~2/3 of PM10 mass and the majority are oxygenated, water-soluble OA species with an average OM/OC = 1.9 (Fig.1). Urban air pollution crises in the Western Balkan will be put in the context of local, regional and global air quality. Finally, we will present the scientific questions opened by SAFICA, including the advantages and limitations of SAFICA data set, and give the recommendations for future studies.
Najdeno v: osebi
Ključne besede: Sarajevo, urban air pollution, PM10, PM2.5
Objavljeno: 26.05.2021; Ogledov: 886; Prenosov: 2
.pdf Polno besedilo (2,01 MB)
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30.
[Rasprava]
Katja Džepina, 2017, objavljeni znanstveni prispevek na konferenci

Opis: Temeljna namjera održavanja okruglog stola i objave ove knjige bila je da se pri obradi pravne zaštite zraka mora polaziti od struke koja je mjerodavna za pitanje očuvanja kvalitete zraka. Pravni pristup tom važnom području mora se na to nastaviti. Pritom se moraju poštivati temeljna pravila odgovarajuće struke, zahtjevi koje ona postavlja i prijedlozi kako poboljšati trenutačno stanje. Rasprava je pokazala da je zadovoljavajući učinak moguć jedino ako primjenjujemo takav pristup. Zadatak je pravnika pravno uobličiti ono što zahtijeva struka koja se bavi kvalitetom zraka. Takav je zahtjev postavljen i u raspravi.
Najdeno v: osebi
Ključne besede: Pravna zaštita zraka, Okrugli stol, Hrvatska Akademija znanosti i umjetnosti, Zagreb, Republika Hrvatska
Objavljeno: 14.06.2021; Ogledov: 710; Prenosov: 0
.pdf Polno besedilo (791,65 KB)
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