2002 summer fires in Lithuania: impact on the Vilnius city air quality and the inhabitants health.

The episodes with highly elevated concentrations of particulate matter (PM10), NOx, and CO were detected in the city of Vilnius between August and September 2002 and possible reasons were analysed. This increase was attributed to emissions from fires in the vicinity of the city of Vilnius when data on fire location and start, wind direction and concentrations of pollutants were analysed. The correlation coefficient between PM10 and CO, NO, NO2, NOx increased during the fire period in comparison with the same correlation after the fire period. During the fire episodes, there was an increase in concentration of ozone precursors, and meteorological conditions were favourable for photochemical reactions. Therefore, the hourly values for ozone exceeded the values common for Vilnius. Generally, during the episodes, the maximum of NO2 concentrations was 2 times higher than the limit value for NO2 laid down in the Council Directives 1999/30/EC [Council Directive 1999/30/EC of 22 April 1999 relating to limit values for sulphur dioxide, nitrogen dioxide and oxides of nitrogen, particulate matter and lead in ambient air. Official Journal L 163, 29/06/1999: 0041-0060], and that of PM10 was even 5.5 times higher than the limit value for PM10. Human health effects study in Vilnius indicated that the incidents of documented respiratory diseases and exacerbation of the bronchial asthma during the fire period were up to 20 times higher in comparison to periods with no fires.

Country-specific correlations across Europe between modelled atmospheric cadmium and lead deposition and concentrations in mosses.

Previous analyses at the European scale have shown that cadmium and lead concentrations in mosses are primarily determined by the total deposition of these metals. Further analyses in the current study show that Spearman rank correlations between the concentration in mosses and the deposition modelled by the European Monitoring and Evaluation Programme (EMEP) are country and metal-specific. Significant positive correlations were found for about two thirds or more of the participating countries in 1990, 1995, 2000 and 2005 (except for Cd in 1990). Correlations were often not significant and sometimes negative in countries where mosses were only sampled in a relatively small number of EMEP grids. Correlations frequently improved when only data for EMEP grids with at least three moss sampling sites per grid were included. It was concluded that spatial patterns and temporal trends agree reasonably well between lead and cadmium concentrations in mosses and modelled atmospheric deposition.

Mosses as biomonitors of atmospheric heavy metal deposition: spatial patterns and temporal trends in Europe.

In recent decades, mosses have been used successfully as biomonitors of atmospheric deposition of heavy metals. Since 1990, the European moss survey has been repeated at five-yearly intervals. Although spatial patterns were metal-specific, in 2005 the lowest concentrations of metals in mosses were generally found in Scandinavia, the Baltic States and northern parts of the UK; the highest concentrations were generally found in Belgium and south-eastern Europe. The recent decline in emission and subsequent deposition of heavy metals across Europe has resulted in a decrease in the heavy metal concentration in mosses for the majority of metals. Since 1990, the concentration in mosses has declined the most for arsenic, cadmium, iron, lead and vanadium (52-72%), followed by copper, nickel and zinc (20-30%), with no significant reduction being observed for mercury (12% since 1995) and chromium (2%). However, temporal trends were country-specific with sometimes increases being found.

Changes in total concentrations and assessed background concentrations of heavy metals in moss in Lithuania and the Czech Republic between 1995 and 2005.

Data on concentrations of heavy metals (As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, V and Zn) in moss collected on the lightly industrialized territory of Lithuania and on the highly industrialized territory of the Czech Republic in 1995, 2000 and 2005 is used to separate the background and anthropogenic contributions to heavy metal concentrations in moss. The distribution of the concentration logarithms allowed us to determine a background mode, and to estimate the background concentration of heavy metals from this mode. The method was then applied for an estimation of the contribution of local sources to the total pollution level in both countries. The average concentrations and the background modes of heavy metals in Lithuania and in the Czech Republic were very similar, except in the case of vanadium, where the background concentration was higher in Lithuania than in the Czech Republic. For most elements, the background concentration in moss had a decreasing tendency in Lithuania and in the Czech Republic between 1995 and 2005, though the concentration of Cu and Hg increased in Lithuania. The variability of chromium concentration in moss differed from the remaining investigated elements in the Czech Republic, and it was expressed as a bimodal lognormal distribution. This variability may be due to simultaneous contamination of moss by chromium from soil and from industrial sources of pollution.

Evaluation of the impact of long-range transport and aerosol concentration temporal variations at the eastern coast of the Baltic Sea.

Ambient particles vary greatly in their ability to affect visibility, climate and human health. The fine fraction of aerosol is responsible for greater and wider effects on human health; thus, investigation of this fraction is very important. Continuous measurements of PM2.5 (particulate matter below 2.5 microm in size) concentrations at the Preila monitoring station started in 2003. During a period of 2 years, the episodes of high daily and semi-hourly concentrations of PM2.5 were measured. These episodes did not depend on the season or time of day. The substantial role of long-range transport of pollutants to these increases in concentration was shown using chemical and statistical analysis. It was found that most of the severe episodes occurred when air masses came from a specific site besides it was established that air masses of different origin were characterized by different mixing layer depth. Lower mixing depth was observed in air masses characterized by higher observed concentrations at the measuring site and vice versa. PM2.5 concentrations showed diurnal and seasonal variations whose pattern reflected the regional origin of the aerosol. The regional pollution level was evaluated by the statistical analysis of PM2.5 concentrations. The background annual average of PM2.5 mass concentration for the eastern coast of the Baltic Sea was 15.1 +/- 0.8 microg m(-3).

Gas-phase mercury in the atmosphere over the southern Baltic Sea coast

Results of atmospheric total gaseous mercury (TGM) measurements performed at two Baltic Sea coastal stations, Peninsula Hel (Poland) and Preila (Lithuania), from June 16 to August 11, 1997, are presented. High time-resolution data were obtained by using automated atomic absorption mercury vapor analyzers (Model Gardis-1A). Analysis of TGM concentration data (directional distribution, correlation with meteorological parameters, diurnal variability) detected the Baltic sea, in particular its southern part and Gulf of Gdansk, as the main gaseous mercury source for the region during the summer months. The source seemed to be activated by solar radiation, air temperature, and, probably, wind.

Estimation of metal uptake efficiencies from precipitation in mosses in Lithuania

The main sources contributing to heavy metal content in mosses in Lithuania were examined by a comparison of heavy metal concentrations in moss and corresponding deposition levels calculated from bulk deposition analysis. Bulk deposition was collected in open areas as well as under the canopy of trees. Uptake efficiencies in moss were calculated for Cd, Cr, Cu, Fe, Mn, Ni, V and Zn. All elements in moss except Pb and Cd appeared to be more or less influenced by sources other than air pollution. The general order of this influence on the heavy metal content in moss was observed as follows: Ni < V < Cr < Zn < Fe < Mn. The contents of Mn and Zn in moss were greatly influenced by leaching from the canopy while Pb was the only element which showed a net metal retention by the canopy. Concentrations of Fe and Cr in moss were dominating due to contribution from soil dust.