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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: 62; Prenosov: 0
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Ključne besede: megacity, submicron aerosols, urban haze, Greater Cairo, hygroscopic aerosols, ammonium chloride
Objavljeno v RUNG: 10.05.2024; Ogledov: 53; Prenosov: 0
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Ključne besede: urban landscapes, UNESCO recommendations, preservation, urban life, traditional communities, creative planning
Objavljeno v RUNG: 02.07.2021; Ogledov: 2134; Prenosov: 0

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: 2029; Prenosov: 136
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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.
Ključne besede: Sarajevo, urban air pollution, PM10, PM2.5
Objavljeno v RUNG: 26.05.2021; Ogledov: 2603; Prenosov: 20
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