A comparative analysis of the causes of air pollution in three cities of the Danube region: implications for the implementation of the air quality directives

The causes of air pollution in three cities of the Danube region (Budapest, Sofia and Zagreb) were studied using datasets of measurements and modelling tools. The contributions from different activity sectors, including natural sources and their geographical origin were quantified. It was observed that most of the pollutants are emitted locally. However, the medium to long range transport may be also considerable. On the basis of the output of the source identification, a series of measures were proposed to deal wtih the pollution problem at local, national and international levels.JRC.H.2-Air and Climat

Sulfur and Nitrogen Depositions in BULGARIA—Model Results and Observations

Atmospheric deposition processes are of primary importance for human health, forests, agricultural lands, aquatic bodies, and ecosystems. South-East Europe is still characterized by numerous hot spots of elevated sulfur deposition, despite the reduction in European emission sources. The purpose of this study is to discuss the results from two chemical transport models and observations for wet and dry depositions of sulfur (S), reduced nitrogen (RDN) and oxidized nitrogen (OXN) in Bulgaria in 2016–2017. The spatial distribution and the domain main deposition values by EMEP MSC-W (model of the MSC-W Centre of the Co-operative Programme for Monitoring and Evaluation of the Long-range Transmissions of Air Pollutants in Europe) and BgCWFS (Bulgarian Chemical Weather Forecast System) demonstrated S wet depositions to be higher than N depositions, and identified a rural area in south-east Bulgaria as a possible hot-spot. The chemical analysis of deposition samples at three sites showed a prevalence of sulfate in the western part of the country, and prevalence of Cl and Na at a coastal site. The comparison between modeled and observed depositions demonstrated that both models captured the prevalence of S wet depositions at all sites. Better performance of BgCWFS with an average absolute value of the normalized mean bias of 16% was found

Sulfur and Nitrogen Depositions in BULGARIA—Model Results and Observations

Atmospheric deposition processes are of primary importance for human health, forests, agricultural lands, aquatic bodies, and ecosystems. South-East Europe is still characterized by numerous hot spots of elevated sulfur deposition, despite the reduction in European emission sources. The purpose of this study is to discuss the results from two chemical transport models and observations for wet and dry depositions of sulfur (S), reduced nitrogen (RDN) and oxidized nitrogen (OXN) in Bulgaria in 2016–2017. The spatial distribution and the domain main deposition values by EMEP MSC-W (model of the MSC-W Centre of the Co-operative Programme for Monitoring and Evaluation of the Long-range Transmissions of Air Pollutants in Europe) and BgCWFS (Bulgarian Chemical Weather Forecast System) demonstrated S wet depositions to be higher than N depositions, and identified a rural area in south-east Bulgaria as a possible hot-spot. The chemical analysis of deposition samples at three sites showed a prevalence of sulfate in the western part of the country, and prevalence of Cl and Na at a coastal site. The comparison between modeled and observed depositions demonstrated that both models captured the prevalence of S wet depositions at all sites. Better performance of BgCWFS with an average absolute value of the normalized mean bias of 16% was found

Black Carbon in Bulgaria—Observed and Modelled Concentrations in Two Cities for Two Months

Black carbon (BC) is one of the particulate matter (PM) components that both affects human health and contributes to climate change. In this study, we present the preliminary results of the investigation of BC concentrations in PM2.5 for two Bulgarian cites—Sofia and Burgas. The parallel PM2.5 samplings were organized in October 2020 and January 2021. The Multi-Wavelength Absorption Black carbon Instrument (MABI) was used for the evaluation of light-absorbing carbon. In addition, we compared the observed BC and PM2.5 values to modelled ones and analyzed the spatial distribution over the country, using data from advanced operational chemical transport models (CTM)—the European (regional) air quality system established at the Copernicus Atmosphere Monitoring Service (CAMS). Generally, the observed BC and PM2.5 values were higher in January than in October for both cities. In October, the model underestimated the observed BC concentrations (Sofia—2.44 μg.m−3, Burgas—1.63 μg.m−3) by 17% and 51%. In January 2021, the observed monthly BC concentrations were higher (Sofia—3.62 μg.m−3, Burgas—1.75 μg.m−3), and the bias of the model was less than that in October, with an overestimation of 22% for Sofia. The relative bias for PM2.5 in October (17% for Sofia and −6% for Burgas) was less than the relative bias in January when the model underestimated PM2.5 monthly mean concentrations by 20% (Sofia) and 42% (Burgas). In addition, we also elaborate on two episodes with high observed BC concentrations in view of the meteorological conditions

Sources and geographic origin of particulate matter in urban areas of the Danube macro-region: the cases of Zagreb (Croatia), Budapest (Hungary) and Sofia (Bulgaria)

The contribution of main PM pollution sources and their geographic origin in three urban sites of the Danube macro-region (Zagreb, Budapest and Sofia) were determined by combining receptor and Lagrangian models. The source contribution estimates were obtained with the Positive Matrix Factorization (PMF) receptor model and the results were further examined using local wind data and backward trajectories obtained with FLEXPART. Potential Source Contribution Function (PSCF) analysis was applied to identify the geographical source areas for the PM sources subject to long-range transport. Gas-to-particle transformation processes and primary emissions from biomass burning are the most important contributors to PM in the studied sites followed by re-suspension of soil (crustal material) and traffic. These four sources can be considered typical of the Danube macro-region because they were identified in all the studied locations. Long-range transport was observed of: a) sulphate-enriched aged aerosols, deriving from SO2 emissions in combustion processes in the Balkans and Eastern Europe and b) dust from the Saharan and Karakum deserts. The study highlights that PM pollution in the studied urban areas of the Danube macro-region is the result of both local sources and long-range transport from both EU and no-EU areas.JRC.C.5-Air and Climat

Ambient particulate matter source apportionment using receptor modelling in European and Central Asia urban areas

This work presents the results of a PM2.5 source apportionment study conducted in urban background sites from 16 European and Asian countries. For some Eastern Europe and Central Asia cities this was the first time that quantitative information on pollution source contributions to ambient particulate matter (PM) has been performed. More than 2200 filters were sampled and analyzed by X-Ray Fluorescence (XRF), Particle-Induced X-Ray Emission (PIXE), and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) to measure the concentrations of chemical elements in fine particles. Samples were also analyzed for the contents of black carbon, elemental carbon, organic carbon, and water-soluble ions. The Positive Matrix Factorization receptor model (EPA PMF 5.0) was used to characterize similarities and heterogeneities in PM2.5 sources and respective contributions in the cities that the number of collected samples exceeded 75. At the end source apportionment was performed in 11 out of the 16 participating cities. Nine major sources were identified to have contributed to PM2.5: biomass burning, secondary sulfates, traffic, fuel oil combustion, industry, coal combustion, soil, salt and “other sources”. From the averages of sources contributions, considering 11 cities 16% of PM2.5 was attributed to biomass burning, 15% to secondary sulfates, 13% to traffic, 12% to soil, 8.0% to fuel oil combustion, 5.5% to coal combustion, 1.9% to salt, 0.8% to industry emissions, 5.1% to “other sources” and 23% to unaccounted mass. Characteristic seasonal patterns were identified for each PM2.5 source. Biomass burning in all cities, coal combustion in Krakow/POL, and oil combustion in Belgrade/SRB and Banja Luka/BIH increased in Winter due to the impact of domestic heating, whereas in most cities secondary sulfates reached higher levels in Summer as a consequence of the enhanced photochemical activity. During high pollution days the largest sources of fine particles were biomass burning, traffic and secondary sulfates.JRC.C.5-Air and Climat