Abstract
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.
Highlights
The atmospheric deposition has been intensively studied worldwide over the last decades, mainly due to concerns over acid rains, eutrophication, trace metal deposition, damages to forests and vegetation, ecosystem health, and global climate change [1,2,3,4]
We focus on sulfur (S), reduced nitrogen (RDN) and oxidized nitrogen (OXN) wet, dry and total depositions in Bulgaria, a country of South-East Europe
A significant difference between the models was noted for the domain-wide maximum annual precipitation, as follows: BgCWFS results were with NMB of about −4%, while EMEP-Chemical transport models (CTM) results were with NMB of about −29%
Summary
The atmospheric deposition has been intensively studied worldwide over the last decades, mainly due to concerns over acid rains, eutrophication, trace metal deposition, damages to forests and vegetation, ecosystem health, and global climate change [1,2,3,4]. The spatial interpolation of relatively sparse observational data to other sites poses difficulties and is still a challenging task [8,9] Another approach to fill in gaps in observational data and to better represent the spatial and temporal distribution of depositions is to apply modeling methods that link emission sources with chemical transport processes, pollutants concentrations and depositions. Chemical Weather Forecasting system (BgCWFS) [25,29,31] Another modeling system that performs simulations for air pollutants, acidification, and eutrophication compounds over Europe on a routine basis was developed at the EMEP Meteorological Synthesizing Centre—West, the EMEP-MSC-W model [32], further denoted as EMEP-CTM. The main objective of this study is to discuss and compare modeling results for wet and dry depositions of sulfur and nitrogen (reduced and oxidized) by BgCWFS and EMEPCTM for Bulgaria. The periods were characterized by elevated values of sulfate and nitrate concentrations in the samples collected at the mountain site
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
