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Size-segregated particle samples were collected using a Berner 5-stage impactor (stages 1-5: 0.05-0.14-0.42-1.2-3.5-10 μm aerodynamic diameter). The means for all 169 days and for different categories of days were used for a characterization. The sorting criteria were (a) the distinction between winter (Wi, November to April) and summer (Su, May to October), (b) the distinction between air mass inflow from a sector West (W, 210 °-320 °) and from a sector East (E, 35 °-140 °). For the assignment of the air mass origin 96-h backward trajectories were used and four categories (WiW, WiE, SuW and SuE) with 48, 18, 42 and 29 days were established. The lowest mean particle mass concentrations were found for SuW and the highest for WiE with relative mass concentration distributions of 5.9, 28.2, 36.5, 18.0, and 11.4 % and 3.5, 22.7, 52.6, 16.7, and 4.5 % for stages 1-5, respectively. The mass closure for water soluble ions, water, organic material (OM) and elemental carbon (EC) accounts for 81-99 % of the gravimetric mass in Wi and for 60-81 % for Su, depending on the stage. The fractions of nitrate were relatively high for WiW while sulphate fractions are high for WiE. The estimated concentrations of secondary organic carbon (SOA) on stage 3 for WiW, WiE, SuW and SuE were 0.32, 1.25, 0.27 and 0.58 μgm³, respectively. The highest amount of SOA is found for WiE, representing 59 % of organic carbon (OC). The highest difference in the percentages of SOA in OC was found between winter (WiW 55 %, WiE 59 %) and summer (SuW and SuE 74 %) indicating photochemical processes during long-range transport. The mean Carbon Preference Indices (CPI) are highest for SuE (stage 4: 7.57 and stage 5: 9.82) resulting mainly from plant wax abrasion in the surrounding forests. For WiE the mean PAH concentration on stage 3 (9.7 ngm) is about five times higher than for WiW, indicating long range transport following domestic heating and other combustion processes. [ABSTRACT FROM AUTHOR]

Atmospheric aerosol particle size distributions at a continental background site in Eastern Germany were examined for a one-year period. Particles were classified using a twin differential mobility particle sizer in a size range between 3 and 800 nm. As a novelty, every second measurement of this experiment involved the removal of volatile chemical compounds in a thermodenuder at 300°C. This concept allowed to quantify the number size distribution of nonvolatile particle cores - primarily associated with elemental carbon, and to compare this to the original non-conditioned size distribution. As a byproduct of the volatility analysis, new particles originating from nucleation inside the thermodenuder can be observed, however, overwhelmingly at diameters below 6 nm. Within the measurement uncertainty, every particle down to particle sizes of 15 nm is concluded to contain a non-volatile core. The volume fraction of non-volatile particulate matter (non-conditioned diameter <800 nm) varied between 10 and 30% and was largely consistent with the experimentally determined mass fraction of elemental carbon. The average size of the non-volatile particle cores was estimated as a function of original non-conditioned size using a summation method, which showed that larger particles (>200 nm) contained more non-volatile compounds than smaller particles (<50 nm), thus indicating a significantly different chemical composition. Two alternative air mass classification schemes based on either, synoptic chart analysis (Berliner Wetterkarte) or back trajectories showed that the volume and number fraction of non-volatile cores depended less on air mass than the total particle number concentration. In all air masses, the non-volatile size distributions showed a more and a less volatile ("soot") mode, the latter being located at about 50 nm. During unstable conditions and in maritime air masses, smaller values were observed compared to stable or continental conditions. This reflects the significant emission of non-volatile material over the continent and, depending on atmospheric stratification, increased concentrations at ground level. [ABSTRACT FROM AUTHOR]

Abstract: PM10 measurements were started in November 1992 at Melpitz site. The mean PM10 concentration in 1993 was 38 μg m−3 in the summer season (May until October) and about 44 μg m−3 in the winter season (November until April). The mean PM10 level decreased until 1999 and varies now in ranges from 20–34 μg m−3 to 17–24 μg m−3 (minimum and maximum mean values for 1999–2008) in winter and summer seasons, respectively. High volume filter samples of particles PM10, PM2.5 and PM1 were characterized for mass, water-soluble ions, organic and elemental carbon from 2004 until 2008. The percentage of PM2.5 in PM10 varies between summer (71.6%) and winter seasons (81.9%). Mean concentrations of PM10, PM2.5 and PM1 in Melpitz were 20, 15, and 13 μg m−3 in 2004, 22, 18, and 13 μg m−3 in 2005, 24, 19, and 12 μg m−3 in 2006 and 22, 17, and 12 μg m−3 in 2007, respectively. In the four winters the rural background concentration PM10 at Melpitz exceeded the daily 50 μg m−3 limit for Europe on 8, 8, 7 and 6 days, respectively. Findings for a simple two-sector-classification of the samples (May 2004 until April 2008) using 96-h backward trajectories for the identification of source regions are: Air masses were transported most of time (60%) from the western sector and secondly (17%) from the eastern sector. The lowest daily mean mass concentration PM10 were found during western inflow in summer (17 μg m−3) containing low amounts of sulphate (2.4 μg m−3), nitrate (1.7 μg m−3), ammonium (1.1 μg m−3) and TC (3.7 μg m−3). In opposite the highest mean mass concentration PM10 was found during eastern inflow in winter (35 μg m−3) with high amounts of sulphate (6.1 μg m−3), nitrate (5.4 μg m−3), ammonium (3.8 μg m−3) and TC (9.4 μg m−3). An estimation of secondary formed OC (SOA) shows 0.8–0.9 μg m−3 for air masses from West and 2.1–2.2 μg m−3 from East. The seasonal difference can be neglected. The half-hourly measurements of the particle mass concentration PM10 evaluated as mean daily courses using a TEOM® show low values (14–21 μg m−3) in summer and winter for air masses transported from West and the highest concentrations (31–38 μg m−3) in winter for air masses from East. The results demonstrate the influence of meteorological parameters on long-range transport, secondary particle mass formation and re-emission which modify mass concentration and composition of PM10, PM2.5 and PM1. Melpitz site is located in the East of Germany faraway from strong local anthropogenic emissions (rural background). Therefore, this site is suitable for investigation of the influence of long-range transport of air pollution in continental air masses from the East with source regions inside and outside of the European Union. [Copyright &y& Elsevier]