The role of annual circulation and precipitation on national scale deposition of atmospheric sulphur and nitrogen compounds.

Atmospheric circulation and rainfall are important factors controlling the deposition of atmospheric pollutants. This paper aims to quantify the role of these factors in the deposition of sulphur and nitrogen compounds, using case studies in the United Kingdom and Poland. The FRAME model has been applied to calculate deposition for the base year (2005), dry and wet years (2003 and 2000 for the UK and 2003 and 1974 for Poland, respectively), and for years with contrasting annual wind patterns (1986 and 1996 for the UK, and 1998 and 1996 for Poland). Variation in annual wind and rainfall resulted in statistically significant changes in spatial patterns of deposition and the national deposition budget of sulphur and nitrogen compounds in both countries. The deposition budgets of S and N are 5% lower than for the reference year if the dry year is considered in both countries. For the wet year, there is an increase in country total deposition by up to 17%. Years with an increased frequency of eastern winds are associated with an increase in deposition of up to 14% in Poland and 8% in the UK. The national deposition budget is below the average for the years with high frequencies of W winds, especially for the UK (up to 13%). Wet deposition varies due to meteorological factors to a larger extent than dry deposition. In Poland, the changes in national deposition budget due to meteorological factors exceed the changes resulting from emission abatements in years 2000-2009 for nitrogen compounds. In the UK, emission abatements influence the national deposition budget to a larger extent than meteorological changes (except for NH(x)). The findings are important in relation to future climate changes, especially considering the potential increase in annual precipitation. This may lead to an increase in deposition over mountainous areas with sensitive ecosystems, where annual rainfall brings significant load of S and N. Changes in annual wind speed and frequency can modify the spatial pattern of deposition. An increased frequency of W winds will benefit both countries through reduced S and N deposition. NW areas of Poland and the UK will suffer from above-average deposition during years with enhanced easterly flow, and this may result in critical loads for acid and nitrogen deposition being exceeded over the areas that are at present sufficiently protected from acidification and eutrophication, despite the ongoing emission abatements.

Modelling deposition and air concentration of reduced nitrogen in Poland and sensitivity to variability in annual meteorology.

The relative contribution of reduced nitrogen to acid and eutrophic deposition in Europe has increased recently as a result of European policies which have been successful in reducing SO(2) and NO(x) emissions but have had smaller impacts on ammonia (NH(3)) emissions. In this paper the Fine Resolution Atmospheric Multi-pollutant Exchange (FRAME) model was used to calculate the spatial patterns of annual average ammonia and ammonium (NH(4)(+)) air concentrations and reduced nitrogen (NH(x)) dry and wet deposition with a 5 km × 5 km grid for years 2002-2005. The modelled air concentrations of NH(3) and dry deposition of NH(x) show similar spatial patterns for all years considered. The largest year to year changes were found for wet deposition, which vary considerably with precipitation amount. The FRAME modelled air concentrations and wet deposition are in reasonable agreement with available measurements (Pearson's correlation coefficients above 0.6 for years 2002-2005), and with spatial patterns of concentrations and deposition of NH(x) reported with the EMEP results, but show larger spatial gradients. The error statistics show that the FRAME model results are in better agreement with measurements if compared with EMEP estimates. The differences in deposition budgets calculated with FRAME and EMEP do not exceed 17% for wet and 6% for dry deposition, with FRAME estimates higher than for EMEP wet deposition for modelled period and lower or equal for dry deposition. The FRAME estimates of wet deposition budget are lower than the measurement-based values reported by the Chief Inspectorate of Environmental Protection of Poland, with the differences by approximately 3%. Up to 93% of dry and 53% of wet deposition of NH(x) in Poland originates from national sources. Over the western part of Poland and mountainous areas in the south, transboundary transport can contribute over 80% of total (dry + wet) NH(x) deposition. The spatial pattern of the relative contribution of national sources to total deposition of NH(x) may change significantly due to the general circulation of air.

The effect of emission from coal combustion in nonindustrial sources on deposition of sulfur and oxidized nitrogen in Poland.

Poland has one of the largest sulfur and nitrogen emissions in Europe. This is mainly because coal is a main fuel in industrial and nonindustrial combustion. The aim of this paper is to assess the amount of sulfur and nitrogen deposited from SNAP sector 02 (nonindustrial sources) coal combustion. To assess this issue, the Fine Resolution Atmospheric Multipollutant Exchange (FRAME) model was used. The results suggest that industrial combustion has the largest impact on deposition of oxidized sulfur, whereas the oxidized nitrogen national deposition budget is dominated by transboundary transport. The total mass of pollutants deposited in Poland, originating from nonindustrial coal combustion, is 45 Gg of sulfur and 2.5 Gg of nitrogen, which is over 18% of oxidized sulfur and nearly 2% of oxidized nitrogen deposited. SNAP 02 is responsible for up to 80% of dry-deposited sulfur and 11% of nitrogen. The contribution to wet deposition is largest in central Poland in the case of sulfur and in some areas can exceed 11%. For oxidized nitrogen, nonindustrial emissions contribute less than 1% over the whole area of Poland. The switch from coal to gas fuel in this sector will result in benefits in sulfur and nitrogen deposition reduction.

Chemical Characterization of Dew Water Collected in Different Geographic Regions of Poland.

The results of a dew monitoring program performed in Poland with the aim to outline the chemical composition of dew water in meteorological context are presented. Dew samples were collected from eight measurement stations from August 2004 to November 2006. Taking into account the type of land use and characteristics of pollutant emission, sampling sites were divided into the following categories: rural, coastal urban and inland urban stations. Selected anions and cations as well as formaldehyde and sum of phenols were determined. The average TIC (Total Inorganic Ionic Content) values in dew samples ranged from 0.83 to 3.93 between individual stations with 10.9 meq/L as the highest daily value of TIC measured. The average TIC values observed in dew at all stations were at a similar level (2.46 meq/L) when compared with hoarfrost (2.86 meq/L). However, these values were much higher in comparison with other kinds of atmospheric water like precipitation (wet only; 0.37 meq/L) or fog/cloud (1.01 meq/L). The pH values of dew water ranged from 5.22 to 7.35 for urban coastal stations, from 5.67 to 8.02 for urban inland stations and from 4.16 to 8.76 for dew samples collected in the rural area. HCHO was found in 97 % of dew samples, with concentrations ranging from 0.010 to 5.40 meq/L. Excluding stations near the seashore, where the contribution of Na⁺ and Cl- increased, the most important ions were sulphates. A very low contribution of NO3- and noticeable increase of Ca2+ which were not observed in the case of precipitation and fog water, were typical in all stations. The contribution of ammonium ion was two times higher at rural stations as a result of agricultural ammonia emissions. The strongest correlations were noticed between the sum of acidifying anions SO42- + NO3- and Ca2+ ion for all urban and rural stations. A very strong correlation was also observed for Na+ and Cl⁻ ions in urban coastal stations, as a natural consequence of the location of these stations close to the sea. It was proved that thermal stratification, direction of circulation and local breeze circulation control the atmospheric chemistry at ground level, where dew is formed. The highest TIC values at urban stations were associated with anticyclonic weather, while at rural sites with cyclonic weather situations. The chemistry of dew water in urban coastal stations was closely related to local breeze circulation in the warm season, mainly in the form of diurnal breeze causing a significant increase of the concentration of Na⁺ and Cl⁻ions. Thus, dew can be a good indicator of the atmospheric pollution level at a given site. Taking into account both high TIC values and the annual water equivalent estimated at around 50 mm, dew is a considerable factor of wet deposition, responsible for an additional 60 % of pollutant input into the ground when compared with precipitation.

Progressing Pollutant Elution from Snowpack and Evolution of its Physicochemical Properties During Melting Period-a Case Study From the Sudetes, Poland.

Main aim of the work assumed recognition of physicochemical changes in snowpack occurring during the melting period. Properties of snow cover had been identified at two sites in Western Sudetes mountains (860 and 1228 m asl) in SW Poland since the end of January, and monitored until the disappearance of snow in late Spring. Snow pit measurements and sample collection at both sites were made followed by chemical analyses with the use of ionic chromatography. The results were compared for subsequent stages of snowpack evolution. Thermometers installed above the ground during summer in one site (860 m asl) helped to identify the thermal gradient existing inside snow during winter. During studies, special attention was paid to the pollutant elution with determination the different release rates of individual ions from the snow cover. Results of chemical analysis showed that during the thaw, the first portions of meltwater were responsible for drainage into the ground a substantial part of the impurities. During the first two weeks of thaw at higher elevated site, pollutants released from the snow cover load amounted to 123.5 mMol·m-2. In those days, there was a release to the ground of approximately 74, 74, and 57 %, respectively of H+, NO3-, and SO42- ions contained in the snow cover, while only 14 % of snow mass in the form of meltwater was released.