Kostadin Ganev

On the origin of SO2 above northern Greece

This paper describes the sources contributing to two seasonal peaks in columnar SO2 amounts measured with a Brewer spectrophotometer at Thessaloniki, Northern Greece since 1982. The SO2 Brewer measurements combined with those at ground level, meteorological analysis and numerical simulations provide estimates on the contribution of local and remote sources to the SO2 column. It is shown that more than 50% of the observed SO2 column can be attributed to lignite-burning sources in Bulgaria, Romania and former Yugoslavia, this percentage rising to 70% at periods with NE flow at 850 hPa. Winds from the NW-N-NE contribute around 60% to the observed mean SO2 column during winter and 75% during the summer. When including all wind directions at 850 hPa, the Greek sources, including the lignite-burning power plant complexes to the WSW of the city, contribute around 40% to the SO2 column. These results are in qualitative agreement with independent observations from inversion of GOME measurements.

Accounting for the mesoscale effects on the air pollution in some cases of large sulfur pollution in Bulgaria or Northern Greece

The objective of the present work is to demonstrate the influence of the meso-scale dynamic phenomena on the larger scale air pollution characteristics. A limited set of episodes with very large sulphur pollution in Bulgaria or Northern Greece is chosen for the study. A 3D quasi-hydrostatic model of the meso-scale dynamics, based on the Businesque approximation (the formulation of Guthman) is used for the purpose. Some numerical experiments for the Balkan Peninsula are carried out under different background (synoptic) conditions. The simulated flow systems outline the main topography effects, typical for the region, such as slope winds, channelling of the air flows or blocking effects. Numerical simulations of the air pollution transport are also carried out, with and without accounting for the meso-scale deformations of the wind field. The comparison of the air pollution characteristics, obtained in both the cases demonstrates that the underlying surface heterogeneity in some of the synoptic situations may have influence not only on the detailed air pollution field in the region, but also on some larger scale pollution characteristics – the total pollution quantity in the air above the countries, the mean surface concentration, the pollution fluxes trough the country boundaries, dry and wet deposition.

Exchange of sulfur pollution between Bulgaria and Greece

The EMAP model (Eulerian Model for Air Pollution) is applied for calculating the sulfur concentration and deposition fields for 1995 as based upon Bulgarian and Greek sources. The country-to-country budgets show that about 4% of the sulfur oxides emitted by Bulgaria are deposited over Greek territory, estimated at 28 kt S. Only 2% of sulfur compounds emitted by Greece are deposited over Bulgaria, estimated at 6.2 kt S for 1995. This data is in agreement with EMEP/MSC-W estimates and provides more details concerning time and space. The results can be used in decision-making, negotiating and the development of contamination strategies.

Grid computing for atmospheric composition studies in Bulgaria

Three Grid applications from the SEE-GRID-SCI Environmental VO are developed by the Bulgarian project team: Climate Change Impact on Air Quality (CCIAQ); Multi-scale atmospheric composition modeling (MSACM); Modeling System for Emergency Response to the Release of Harmful Substances in the Atmosphere (MSERRHSA). The three applications concern problems of significant socio-economic significance. They are all dedicated to air pollution studies, but address different goals and so face different problems and requirements. The applications are briefly presented in the paper. Examples of the different applications validations are given. Some application results are shown and commented.

Contribution of biogenic emissions to the atmospheric composition of the Balkan Region and Bulgaria

The present work aims at studying the local to regional atmospheric pollution transport and transformation processes over the Balkan Peninsula and Bulgaria. The US EPA models-3 system is chosen as a modelling tool. As the NCEP global analysis data with one degree resolution is used as meteorological background, the models nesting capabilities are applied for downscaling the simulations to a 9 km resolution over Balkans and 3 km over Bulgaria. The TNO emission inventory is used as emission input. Special pre-processing procedures are created for introducing temporal profiles and speciation of the emissions. The study is based on a large number of numerical simulations carried out for two emission scenarios – with all the emissions and with biogenic emissions excluded. Some results from both emission scenarios which make it possible to evaluate the contribution of biogenic emissions are demonstrated in the paper.

Accounting for effects of wind rotation in the PBL on the plume characteristics

The present work aims at demonstrating the influence of a number of dynamic effects in the PBL on the pollution concentration from a point source. The diffusion plume model applied in the study is based on the moment method. Limited number of numerical simulations, based on a more general model of a non-stationary, stratified, baroclinic PBL over a sloping terrain are carried out. The results are demonstrated mostly in the terms of mean cross-wind displacement and dispersion and are discussed versus the classic Gaussian plume characteristics behaviour. The differences demonstrate the joint influence of the wind rotation and vertical turbulent exchange on the admixture field pattern.

Study of the pollution exchange between Bulgaria and northern Greece

The present work aims at a detailed study and explanation of the pollution transport in the air basin over south-western Bulgaria and northern Greece and assessment of the air pollution exchange between Bulgaria and Greece. Some well-known specific climatic air pollution effects were studied and explained. Calculations were made of the SO2 pollution of the Balkan Peninsula from both Greek and Bulgarian sources for 1995, and the country-to-country pollution budget diagrams were built. Days with extreme mean concentration for Bulgaria and northern Greece were picked out, and some further specification of the contribution of the different sources in both the countries to these cases of extreme pollution was made. Some preliminary studies of possible mesoscale effects on the pollution exchange between Bulgaria and northern Greece were carried out. A three-layer pollution transport model with a more complex chemistry block was introduced, and some preliminary simulations of the transport of sulfur and nitrogen...

Climate change impact assessment of air pollution levels in bulgaria

The presented work is aiming at climate change impacts and vulnerability assessment in Bulgaria Climate change may affect exposures to air pollutants by affecting weather and thereby local and regional pollution concentrations Local weather patterns influence atmospheric chemical reactions and can also affect atmospheric transport and deposition processes. US EPA Models-3 System for a region with resolution of 10 km covering Bulgaria is exploited here The meteorological background is produced by the climatic version of ALADIN weather forecast system TNO emission inventory for 2000 is used The chemical boundary conditions are extracted from 50-km resolution runs over Europe made in Aristotle University of Thessaloniki, Greece Calculations for the period 1991-2000 are performed, results presented in a study For year 2000, some scenarios are run, results compared with measured data.

Analysis of the Processes Which Form the Air Pollution Pattern over Bulgaria

The air pollution transport is subject to different scale phenomena, each characterized by specific atmospheric dynamics mechanisms, chemical transformations, typical time scales etc. The air pollution pattern is formed as a result of interaction of different processes. The present study attempts to make some evaluations of the contribution of different processes to the local to regional pollution over Bulgaria. The US EPA Model-3 system is chosen as a modelling tool. As the NCEP Global Analysis Data with one degree resolution is used as meteorological background, the MM5 and CMAQ nesting capabilities are applied for downscaling the simulations to a 3 km resolution over Bulgaria.

A comparative analysis of different conventional and non-local stable/neutral PBL regimes and their parameterisation in air pollution problems

The basic dynamic and diffusion characteristics in several types stable/neutral PBL turbulent regimes are determined on the basis of applied oriented complex method, which accounts for the influence of free-flow stability effects is demonstrated. In particular the results can be used for parameterisation of dynamic and diffusion processes in PBL under such conditions.