1. Emission of volatile organic compounds from residential biomass burning and their rapid chemical transformationsMaximillien Desservettaz, Michael Pikridas, Iasonas Stavroulas, Aikaterini Bougiatioti, Eleni Liakakou, Nikolaos Hatzianastassiou, Jean Sciare, Nikolaos Mihalopoulos, Efstratios Bourtsoukidis, 2023, izvirni znanstveni članek Opis: Biomass combustion releases a complex array of Volatile Organic Compounds (VOCs) that pose significant challenges to air quality and human health. Although biomass burning has been extensively studied at ecosystem levels, understanding the atmospheric transformation and impact on air quality of emissions in urban environments remains challenging due to complex sources and burning materials. In this study, we investigate the VOC emission rates and atmospheric chemical processing of predominantly wood burning emissions in a small urban centre in Greece. Ioannina is situated in a valley within the Dinaric Alps and experiences intense atmospheric pollution accumulation during winter due to its topography and high wood burning activity. During pollution event days, the ambient mixing ratios of key VOC species were found to be similar to those reported for major urban centres worldwide. Positive matrix factorisation (PMF) analysis revealed that biomass burning was the dominant emission source (>50 %), representing two thirds of OH reactivity, which indicates a highly reactive atmospheric mixture. Calculated OH reactivity ranges from 5 s−1 to an unprecedented 278 s−1, and averages at 93 ± 66 s−1 at 9 PM, indicating the presence of exceptionally reactive VOCs. The highly pronounced photochemical formation of organic acids coincided with the formation of ozone, highlighting the significance of secondary formation of pollutants in poorly ventilated urban areas. Our findings underscore the pressing need to transition from wood burning to environmentally friendly sources of energy in poorly ventilated urban areas, in order to improve air quality and safeguard public health.
Ključne besede: biomass burning, urban air quality, VOCs, emission factors, source apportionment
Objavljeno v RUNG: 13.05.2024; Ogledov: 112; Prenosov: 1
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2. Yearlong variability of oxidative potential of particulate matter in an urban Mediterranean environmentD. Paraskevopoulou, Aikaterini Bougiatioti, Iasonas Stavroulas, T. Fang, Maria Lianou, Eleni Liakakou, Evangelos Gerasopoulos, R. Weber, Athanasios Nenes, Nikolaos Mihalopoulos, 2019, izvirni znanstveni članek Opis: The oxidative potential (OP) of fine and coarse fractions of ambient aerosols was studied in the urban environment of Athens, Greece. OP was quantified using a dithiothreitol (DTT) assay, applied to the water soluble fraction of aerosol that was extracted from 361 fine and 84 coarse mode of 24-h and 12-h filter samples over a one-year period. During the cold period, samples were collected on a 12-h basis, to assess the impact of night-time biomass burning emissions from domestic heating on OP. The chemical characteristics of aerosols were measured in parallel using an Aerosol Chemical Speciation Monitoring (ACSM) and a 7-wavelength Aethalometer. A source apportionment analysis on the ACSM data resulted in the identification of organic aerosol (OA) factors on a seasonal basis. A good correlation of OP with NO3−, NH4+, BC (Black Carbon), Organics and LV-OOA (low volatility oxygenated OA) was found during winter, revealing the importance of combustion and aging processes for OP. During the summertime, a good correlation between OP and SO4−2 and NH4+indicates its association with regional aerosol – thus the importance of oxidative aging that reduces its association with any characteristic source. Multiple regression analysis during winter revealed that highly oxygenated secondary aerosol (LV-OOA) and, to a lesser extent, fresh biomass burning (BBOA) and fossil fuel (HOA) organic aerosol, are the prime contributors to the OP of fine aerosol, with extrinsic toxicities of 54 ± 22 pmol min−1 μg−1, 28 ± 7 and 17 ± 4 pmol min−1μg−1, respectively. In summer, OP cannot be attributed to any of the identified components and corresponds to a background aerosol value. In winter however, the regression model can reproduce satisfactorily the water soluble DTT activity of fine aerosol, providing a unique equation for the estimation of aerosol OP in an urban Mediterranean environment.
Ključne besede: oxidative potential, reactive oxygen species, DTT assay, particulate matter, urban aerosol
Objavljeno v RUNG: 13.05.2024; Ogledov: 113; Prenosov: 0
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3. Optical properties of near-surface urban aerosols and their chemical tracing in a Mediterranean city (Athens)Dimitris Katsanos, Aikaterini Bougiatioti, Eleni Liakakou, Dimitris G. Kaskaoutis, Iasonas Stavroulas, D. Paraskevopoulou, Maria Lianou, Basil E. Psiloglou, Evangelos Gerasopoulos, Christodoulos Pilinis, 2019, izvirni znanstveni članek Opis: One-year measurements (October 2016–September 2017) of aerosol optical properties in the Athens urban environment were analyzed; for closure purposes, the results were supported by data of chemical composition of the non-refractory submicron aerosol fraction acquired with an Aerosol Chemical Speciation Monitor (ACSM). Both the spectral scattering (bsca) and absorption (babs) coefficients exhibit a pronounced annual variability with higher values (63.6 Mm–1 at 550 nm and 41.0 Mm–1 at 520 nm, respectively) in winter, due to domestic heating releasing increased carbonaceous emissions and the shallow mixing layer trapping aerosols near the surface. Much lower values (33.5 Mm–1 and 22.9 Mm–1 for bsca and babs, respectively) are found during summer, indicating rather aged aerosols from regional sources. The estimations of the dry spectral single scattering albedo (SSA), scattering (SAE) and absorption (AAE) Ångström exponents focus on the seasonality of the urban aerosols. The high SAE (~2.0) and low SSA (0.62 ± 0.11) values throughout the year indicate the dominance of fine-absorbing aerosols from fossil-fuel combustion, while the high AAE (~1.5) in winter suggests enhanced presence of biomass-burning aerosols. Pronounced morning and late evening/night peaks are found in both bsca and babs during winter, coinciding with the morning traffic rush hour and increased residential wood burning in the evening, while in the other seasons, the diurnal patterns flatten out. The wind speed strongly affects the aerosol loading and properties in winter, since for winds below 3 m s–1, a high increase in bsca and babs is observed, consistent with low dilution processes and hazy/smoggy conditions. Our closure experiments indicate a good agreement (R2 = 0.91, slope = 1.08) between the reconstructed and measured bsca values and reveal that organic matter contributes about half of the sub-micron mass in winter, followed by sulfate (~40%) and nitrate (10%, only in winter) aerosols.
Ključne besede: urban aerosols, light scattering, absorption, chemical species, wood burning, Athens
Objavljeno v RUNG: 10.05.2024; Ogledov: 122; Prenosov: 2
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4. Integrating in situ measurements and city scale modelling to assess the COVID–19 lockdown effects on emissions and air quality in Athens, GreeceGeorgios Grivas, Eleni Athanasopoulou, Anastasia Kakouri, Jennifer Bailey, Eleni Liakakou, Iasonas Stavroulas, Panayiotis Kalkavouras, Aikaterini Bougiatioti, Dimitris G. Kaskaoutis, Michel Ramonet, 2020, izvirni znanstveni članek Opis: The lockdown measures implemented worldwide to slow the spread of the COVID–19 pandemic have allowed for a unique real-world experiment, regarding the impacts of drastic emission cutbacks on urban air quality. In this study we assess the effects of a 7-week (23 March–10 May 2020) lockdown in the Greater Area of Athens, coupling in situ observations with estimations from a meteorology-atmospheric chemistry model. Measurements in central Athens during the lockdown were compared with levels during the pre- and post-lockdown 3-week periods and with respective levels in the four previous years. We examined regulatory pollutants as well as CO2, black carbon (BC) and source-specific BC components. Models were run for pre-lockdown and lockdown periods, under baseline and reduced-emissions scenarios. The in-situ results indicate mean concentration reductions of 30–35% for traffic-related pollutants in Athens (NO2, CO, BC from fossil fuel combustion), compared to the pre-lockdown period. A large reduction (53%) was observed also for the urban CO2 enhancement while the reduction for PM2.5 was subtler (18%). Significant reductions were also observed when comparing the 2020 lockdown period with past years. However, levels rebounded immediately following the lift of the general lockdown. The decrease in measured NO2 concentrations was reproduced by the implementation of the city scale model, under a realistic reduced-emissions scenario for the lockdown period, anchored at a 46% decline of road transport activity. The model permitted the assessment of air quality improvements on a spatial scale, indicating that NO2 mean concentration reductions in areas of the Athens basin reached up to 50%. The findings suggest a potential for local traffic management strategies to reduce ambient exposure and to minimize exceedances of air quality standards for primary pollutants.
Ključne besede: pandemic, urban air pollution, traffic, chemical transport model, TAPM, mapping
Objavljeno v RUNG: 10.05.2024; Ogledov: 122; Prenosov: 2
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5. Submicron aerosol pollution in Greater Cairo (Egypt) : a new type of urban haze?Aliki Christodoulou, Spiros Bezantakos, Efstratios Bourtsoukidis, Iasonas Stavroulas, Michael Pikridas, Konstantina Oikonomou, Minas Iakovides, Salwa K. Hassan, Mohamed Boraiy, Mostafa El-Nazer, 2024, izvirni znanstveni članek Ključne besede: megacity, submicron aerosols, urban haze, Greater Cairo, hygroscopic aerosols, ammonium chloride
Objavljeno v RUNG: 10.05.2024; Ogledov: 103; Prenosov: 2
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6. Sarajevo Canton Winter Field Campaign 2018 (SAFICA) : aerosol source apportionment and oxidative potential in a global hotspotKatja Džepina, Griša Močnik, 2021, objavljeni povzetek znanstvenega prispevka na konferenci Opis: Nowadays, urban centres in countries of the Western Balkan (e.g., Bosnia and Herzegovina, B&H) are experiencing some of the poorest air quality worldwide due to the extensive use of solid fuels and an old vehicle fleet. Western Balkan countries lack state-of-the-science atmospheric research despite high levels of ambient pollution, making the efforts to understand the mechanisms of their air pollution imperative. Sarajevo, the capital of B&H, is situated in a basin surrounded by mountains. 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 online aerosol measurements and collection of daily, continuous filter PM10 samples for offline 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 (both 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 the following offline 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, water-soluble organic carbon, polycyclic aromatic hydrocarbons (11), levoglucosan, organic acids (16) and 14C total carbon content to evaluate OA chemical composition. 3) Major inorganic anions and cations to evaluate aerosol inorganic species. 4) Aerosol metal content determined by three techniques (AAS, ICP-MS and EESI). 5) Aerosol oxidative potential (OP) by two methods (AA and DTT) to evaluate the ability of particles to generate adverse health effects causing reactive oxygen species. SAFICA online measurements of black carbon (Aethalometer) and the particle number conc. (CPC and OPS) enabled the insights into the daily evolution of primary pollutants and an assessment of aerosol size and number distribution.
The combined SAFICA results for field and lab measurements will be presented. Our results show that carbonaceous aerosols make ~2/3 of PM10 mass and the majority are oxygenated, water-soluble OA species with an average OM/OC = 1.9 (Fig.1). Absolute OP levels are very high compared to other sites globally. However, more work is needed to estimate the contributions of different aerosol sources and species to total aerosol OP. 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 and give suggestions for future studies.
Ključne besede: Sarajevo, Bosnia and Herzegovina, urban air pollution, PM10, PM2.5
Objavljeno v RUNG: 03.09.2021; Ogledov: 2087; Prenosov: 47
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8. URBiNAT, Heritage and Circular EconomyAcri Marco, Dobričić Saša, prispevek na konferenci brez natisa Opis: The presentation is showing the origin of the concept of the cultural corridor in Rijeka in the CLIC project as originated from the URBiNAT project
Ključne besede: Cultural Corridor, Healthy Corridor, Circular Eocnomy, Adaptive Reuse, Cultural Heritage, Historic Urban Landscape, Built Environment, urban regeneraiton, heritage conservation, heritage valorisaiton, Common Goods, Sustainable Heritage
Objavljeno v RUNG: 22.06.2021; Ogledov: 2207; Prenosov: 0
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9. Regenerating the historic urban landscape through circular bottom-up actions: the urban seeding process in RijekaMarco Acri, Saša Dobričić, Maja Debevec, 2021, izvirni znanstveni članek Opis: The increasing pressure on urban resilience and the parallel interest in the preservation of the Historic Urban Landscape (HUL) have opened new frontiers of research that find, in the principles of the circular economy, good responses. Cities need to remake themselves from pure consumption to more resilient and circular centers, finding inspiration in their cultural and natural heritage and the history that generated it. The City of Rijeka, Croatia, one of the partners in the CLIC project (an EU-funded Horizon 2020 research project entitled “Circular models Leveraging Investments in Cultural heritage adaptive reuse”), represents an exceptional example of how to manage the change from an industrial port city to a more sustainable and citizen-oriented living space, looking at the potentials of the cultural and historical layers as opportunities for the population. The City of Rijeka, aware of such potentials, applied successfully as a European Capital of Culture 2020 (ECoC 2020), while unlikely facing the negative impacts of the COVID-19 pandemic. In Rijeka, thanks to the CLIC Heritage Innovative Partnership (HIP) program, the efforts to associate the circular economy and historic urban landscape benefit from an exceptional local awareness of the urban cultural and natural heritage, permitting the elaboration of the cultural corridor concept. By using the historical river of the city, the Rječina, as a connecting line of several heritage assets leading toward the Sea waterfront, the cultural corridor represents a space of culture creation based on continuity and proximity, where all citizens can securely reappropriate dismissed parts of the city, similar to the commons’ management practice. The cultural corridor has been imagined as a spatial implementation model that needs actions to be actuated. A set of actions was designed through the urban seeding process, tested in a workshop methodology, meant to address the HUL regeneration through an awareness-raising and cocreation approach by codesigning through situated learning, possible permanent or temporary actions, activities, assets to be replicated in the corridor and, per extension, in the entire city. This article will explain the way the cultural corridor concept and urban seeding were generated in the City of Rijeka, giving evidence of the motivations and the proposals made in parallel with the existing initiatives of the city and its cultural movements.
Ključne besede: urban regeneration, historic urban landscape, circular economy, adaptive reuse, cultural corridor, urban seeding
Objavljeno v RUNG: 08.06.2021; Ogledov: 2042; Prenosov: 136
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10. Chemical characterization of atmospheric aerosols in the Sarajevo Canton : results of 2017-2018 Sarajevo Canton Winter Field Campaign (SAFICA)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.
Ključne besede: atmospheric aerosol, Sarajevo, urban air pollution, SAFICA 2018
Objavljeno v RUNG: 26.05.2021; Ogledov: 2381; Prenosov: 0
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