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Abstract: High values of aerosol black carbon (BC) and chemical compounds were recorded at the background station in Preila (55°55′N, 21°00′E, 5m a.s.l., Lithuania) during the 31 Mach–3 April, 2008 and 2–8 April, 2009 periods. Temporal and spatial evolution and transport of biomass burning (BB) aerosols observed within this period were explained by the air mass backward trajectory analysis in conjunction with the fire detections data produced by the MODIS Rapid Response System. The surface measurements and analysis for chemical characterization of aerosol, stable carbon isotope ratio δ 13C as well as calculation of Ångström exponent of the absorption coefficient done separately for shorter and longer wavelengths (i.e., α =370–520nm and α =660–950nm) showed that high levels of aerosol BC and chemical compounds were related to the transport of air masses rich in BB products from Kaliningrad region, Ukraine and southwestern part of Russia caused by active grass burning during the period of our study. During this event the aerosol particle number concentration of 1-hour average reached 30000cm− 3, BC — 11000ngm− 3, while normally average concentration values are about 3100cm− 3 and 750ngm− 3, respectively. During the event in 2008 the highest mean values of Ångström exponent of the absorption coefficient α 370 – 520 and α 590 – 950nm were observed (2.4±0.1 and 1.5±0.1, respectively), as well as during the event in 2009 the peak values were determined (2.3±0.1 and 1.6±0.1, respectively). The negative carbon isotopic mean value (−30.9±0.2‰) during 31 March–2 April 2008 obviously indicates that a major part of carbon mass in aerosol particles transferred by the continental air masses is from wildfire location. [Copyright &y& Elsevier]

The chemical composition of submicron aerosol particles was characterized using an aerosol chemical speciation monitor (ACSM) at a mixed-mature forest site at the Aukštaitija Integrated Monitoring Station in the eastern part of Lithuania. Four organic aerosol (OA) factors were determined by positive matrix factorization (PMF) analysis applied for the ACSM data: semi-volatile oxygenated OA (SVOOA, the contribution to the total OA mass concentration was 33%), low-volatile oxygenated OA (LVOOA, 39%), cooking related OA (COA, 15%) and biomass burning OA (BBOA, 13%). In our study secondary organic aerosol (SOA) has been identified as one of the most important contributors to the submicron particle (PM 1) mass concentration. A comparison between SVOOA and submicron forest organic aerosol mass (SFOM) was performed, and a good correlation of 0.75 between them was found. In our study the SOA concentration dependence on temperature was explored in 3 means: firstly, by investigating aerosol mass spectra measured during hot and cold days. It has been found that during hot days events signal intensities of m/z 42, 43, 45, 53 and 59 were about 2.1–2.7 times higher compared to those during cold days. Secondly, by investigating the temperature dependence of SVOOA and estimated SFOM. It has been found that SFOM and SVOOA concentrations increase with temperature. Thirdly, by assessing the influence of temperature related stomatal conduction on SVOOA concentration: no direct influence on SVOOA concentration was observed. • When temperature rises, the daytime SFOM concentration increases non-linearly. • Signal intensities of m/z 42, 43, 45, 53 & 59 are twice higher during hot days. • There is no direct influence of stomatal conduction on SVOOA concentration. [ABSTRACT FROM AUTHOR]

This study presents results of research on urban aerosol particles with a focus on the aerosol particle number concentration (PNC) and the particle size distribution. The real time measurements of aerosol PNC (>4.5nm) and number size distributions (9–840nm) were performed. The seasonal variations essentially comprised the minimum monthly mean in October 2010 (3400±3000cm−3) and the maximum in April 2011 (19,000±15,000cm−3). The mean annual PNC was 10,000±8000cm−3 with an average mode size of 30–50nm. The presence of strong diurnal patterns in aerosol PNC was evident as a direct effect of three sources of aerosol particles (nucleation, traffic, and residential heating). Hybrid receptor modeling potential source contribution function (PSCF) and concentration weighted trajectory (CWT) were used by incorporating 72-h backward trajectories and measurements of PNC in Vilnius. The results of trajectory clustering and the PSCF method demonstrated that possible additional source areas contributing to the elevated particle number concentration in Vilnius could be industrial areas in central Europe. Principal component analysis (PCA) revealed highest loadings for PNC, PM10, NOx, NO, NO2 and SO2 concentrations, indicating combustion processes occurring in vehicle engines and use of sulfur-containing fossil fuels for residential heating. [ABSTRACT FROM AUTHOR]

European emissions data have been reported during the last 40 years under the Cooperative Programme for Monitoring and Evaluation of the Long-range Transmission of Air Pollutants in Europe (EMEP), launched by the UNECE Convention on Long-range Transboundary Air Pollution (CLRTAP). In this paper, long-term continuous data of gaseous and particulate air pollutants concentrations measured over a period of 36 years (1981–2017) from a coastal background EMEP air quality monitoring site in Preila, Lithuania, were analyzed. All the analyzed S- and N- species decreased during the 1981–2017 period except for nitrate concentration, which increased during the 1990s by 170%, and showed minor decreasing trend during the 2000–2017 period. The analysis has shown that despite the 95% and 79% decrease of sulfur dioxide and sulfate concentrations, respectively, sulfate comprised a considerable share of the ion balance. As the concentration of total sulfate decreased remarkably, the sea-related particles portion of the sulfate concentration increased up to 22%. The sulfur dioxide concentration at the Preila station has stabilized since 2015. Separation between the time series of sulfur dioxide and sulfate occurred in 2007–2008 with sulfate exceeding sulfur dioxide concentrations during the latest decade. This indicates the absence of local sulfur dioxide sources and relative increase in contributions by long-range transport of particulate forms of sulfur. • All sulfate and nitrogen species decreased in the SE Baltic region over the 1981–2017 period except for nitrogen in nitrate. • As the concentration of total sulfate decreased, the portion of sulfate in sea-related particles increased to 1/5. • The contribution of sulfate to the charge balance in air is comparable with nitrate and remains considerable. [ABSTRACT FROM AUTHOR]