Project Title: Study on transport processes and deposition of atmospheric pollutants in Bulgaria.
Project № ДН 04/4 - 15.12.2016
Duration: 36 months, start date 15.12.2016.; extended till 27.02.2022.
Funding: Competition for financial support of fundamental research – 2016, National Science Found, Ministry of Education and Science.
Priority area: Earth Sciences
Total Budget: BGN 119 996

Background

The atmospheric deposition is determined by a variety of factors – the strength and type of the emission sources, transport and diffusion processes, microphysical processes involving aerosols, gases and water droplets, chemical transformation of pollutants, as well as the interaction with different types of earth surface (vegetation, soil, water). One of the key processes, that continue to be of concern on global scale, is the long range transport of pollutants. In fact, the main acidifying substances (sulphates and nitrates) have a residence time in the atmosphere of about 4-7 days, so that they can be transported by atmospheric motions thousands of kilometers away from their sources and impact the environment in regions, far-away from pollution sources.

The focus of this project is on the effects of atmospheric transport processes on deposition of pollutants in Bulgaria. The contribution of long range transport of pollutants depends on the region of air mass and cloud formation. The chemical transformations are different for the various reactive gases and for the aerosols, which leads to fractioning and change in the mass of major ions and trace elements during the transport. The territory of Bulgaria is characterized by highly complex terrain, which determines the interaction of atmospheric processes in different horizontal scales. The precipitation pattern is, accordingly, highly non-homogeneous. The study of such processes from Bulgaria is a challenging task, requiring application of various methods and setting up of various methodologies in order to study atmospheric processes and related ecological problems on a long-term basis.

Project Objectives

The overall goal of the project is to gain new knowledge about the atmospheric deposition of pollutants (including sulphates, nitrates and heavy metals) in Bulgaria and built a scientific base for long-term systematic studies on deposition in a region of Europe, identified as poor in data.

The objectives of the proposed research are:

• Estimation of wet and dry deposition of acidifying compounds, trace elements and mercury in the country and in selected regions of it.
• Analysis of the influence of the type of surface (urban, rural, mountain) and the altitude on the chemical deposition of wet samples.
• Study of effects of atmospheric transport processes in different scales on deposition of pollutants in Bulgaria.
• Improvement and optimization of used by the team theoretical and experimental approaches for investigation of atmospheric deposition as a first necessary step towards elaboration of methodology for long-term scientific studies.

Expected Results

The expected scientific results are mainly directed to obtain new knowledge for the atmospheric deposition of pollutants over Bulgaria and the processes of atmospheric transport associated with it. In particular:

• methodologies for experimental observation of different types of deposition (wet, dry and cloud water) in Bulgaria with a focus on Sofia, Ahtopol and Cherni Vrah;
• new experimental data for physical characteristics and chemical composition of atmospheric depositions (acidity, conductivity, main anions - SO₄^2-, NO₃^-, Cl^-, ammonium ions (NH₄⁺), macro and micro elements (Na, K, Mg, Ca, Fe, Si, etc.), some of them heavy, toxic metals (Cd, Zn, Cu, Hg, etc.) in stations with different underlying surfaces (urban, mountainous, coastal);
• estimations of the correlation of various pollutants in the cloud layer and in the sub-cloud washout, as well as estimations of variations in the concentrations of admixtures in the depositions depending on the type and amount of precipitation;
• connections between atmospheric transport at different scales (transboundary long-range transport, regional and local circulations) and depositions of various pollutants will be revealed and synoptic situations associated with high levels of acidifying substances will be identified;
• typical values of the precipitation acidity will be obtained for different areas in Bulgaria (urban, mountainous, coastal);
• data base with all available information on atmospheric deposition over Bulgaria will be created.

List of participants