Research Station Melpitz Research Articles

Residential Wood Combustion in Germany: A Twin-Site Study of Local Village Contributions to Particulate Pollutants and Their Potential Health Effects.

Residential wood combustion contributing to airborne particulate matter (PM10) was studied for 1 year at two sites in the village of Melpitz. Significant excess pollution was observed at the Melpitz center compared to that at the TROPOS research station Melpitz reference site, situated only 700 m away. Local concentration increments at the village site for the combustion PM constituents organic carbon, elemental carbon, levoglucosan, and benzo[a]pyrene were determined under appropriate wind directions, and their winter mean values were 0.7 μg m-3, 0.3 μg m-3, 0.1 μg m-3, and 0.4 ng m-3, representing relative increases over the regional background concentration of 24, 70, 61, and 107%, respectively. Yearly, weekly, and diurnal profiles of village increments suggest residential heating as the dominant source of this excess pollution, mainly originating from wood combustion. Receptor modeling using positive matrix factorization quantified 4.5 μg m-3 wood combustion PM at the village site, representing an increment of 1.9 μg m-3 and an increase of ∼75% over the 2.6 μg m-3 regional background wood combustion PM. This increment varied with season, temperature, and boundary layer height and reached daily mean values of 4-6 μg m-3 during unfavorable meteorological conditions. Potential health effects were estimated and resulted in an all-cause mortality from short-term exposure to wood combustion PM of 2.1 cases per 100,000 inhabitants and year for areas with similar wood smoke levels as observed in Melpitz. The excess cancer risk from the concentrations of polycyclic aromatic hydrocarbons was 6.4 per 100,000. For both health metrics, the very local contributions from the village itself were about 40-50%, indicating a strong potential for mitigation through local-scale policies. A compilation of literature data demonstrates wood combustion to represent a major source of PM pollution in Germany, with average winter-time contributions of 10-20%. The present study quantifies the negative impacts of heating with wood in rural residential areas, where the continuous monitoring of air quality is typically lacking. Further regulation of this PM source is warranted in order to protect human health.

A 1-year aerosol chemical speciation monitor (ACSM) source analysis of organic aerosol particle contributions from anthropogenic sources after long-range transport at the TROPOS research station Melpitz

Abstract. Atmospheric aerosol particles are a complex combination of primary emitted sources (biogenic and anthropogenic) and secondary aerosol resulting from aging processes such as condensation, coagulation, and cloud processing. To better understand their sources, investigations have been focused on urban areas in the past, whereas rural-background stations are normally less impacted by surrounding anthropogenic sources. Therefore, they are predisposed for studying the impact of long-range transport of anthropogenic aerosols. Here, the chemical composition and organic aerosol (OA) sources of submicron aerosol particles measured by an aerosol chemical speciation monitor (ACSM) and a multi-angle absorption photometer (MAAP) were investigated at Melpitz from September 2016 to August 2017. The location of the station at the frontier between western and eastern Europe makes it the ideal place to investigate the impact of long-range transport over Europe. Indeed, the station is under the influence of less polluted air masses from westerly directions and more polluted continental air masses from eastern Europe. The OA dominated the submicron particle mass concentration and showed strong seasonal variability ranging from 39 % (in winter) to 58 % (in summer). It was followed by sulfate (15 % and 20 %) and nitrate (24 % and 11 %). The OA source identification was performed using the rolling positive matrix factorization (PMF) approach to account for the potential temporal changes in the source profile. It was possible to split OA into five factors with a distinct temporal variability and mass spectral signature. Three were associated with anthropogenic primary OA (POA) sources: hydrocarbon-like OA (HOA; 5.2 % of OA mass in winter and 6.8 % in summer), biomass burning OA (BBOA; 10.6 % and 6.1 %) and coal combustion OA (CCOA; 23 % and 8.7 %). Another two are secondary and processed oxygenated OA (OOA) sources: less oxidized OOA (LO-OOA; 28.4 % and 36.7 %) and more oxidized OOA (MO-OOA; 32.8 % and 41.8 %). Since equivalent black carbon (eBC) was clearly associated with the identified POA factors (sum of HOA, BBOA, and CCOA; R2= 0. 87), eBC's contribution to each of the POA factors was achieved using a multilinear regression model. Consequently, CCOA represented the main anthropogenic sources of carbonaceous aerosol (sum of OA and eBC) not only during winter (56 % of POA in winter) but also in summer (13 % of POA in summer), followed by BBOA (29 % and 69 % of POA in winter and summer, respectively) and HOA (15 % and 18 % of POA in winter and summer, respectively). A seasonal air mass cluster analysis was used to understand the geographical origins of the different aerosol types and showed that during both winter and summer time, PM1 (PM with an aerodynamic diameter smaller than 1 µm) air masses with eastern influence were always associated with the highest mass concentration and the highest coal combustion fraction. Since during wintertime CCOA is a combination of domestic heating and power plant emissions, the summer contribution of CCOA emphasizes the critical importance of coal power plant emissions to rural-background aerosols and its impact on air quality, through long-range transportation.

Multi-year ACSM measurements at the central European research station Melpitz (Germany) – Part 1: Instrument robustness, quality assurance, and impact of upper size cutoff diameter

Abstract. The aerosol chemical speciation monitor (ACSM) is nowadays widely used to identify and quantify the main components of fine particles in ambient air. As such, its deployment at observatory platforms is fully incorporated within the European Aerosol, Clouds and Trace Gases Research Infrastructure (ACTRIS). Regular intercomparisons are organized at the Aerosol Chemical Monitoring Calibration Center (ACMCC; part of the European Center for Aerosol Calibration, Paris, France) to ensure the consistency of the dataset, as well as instrumental performance and variability. However, in situ quality assurance remains a fundamental aspect of the instrument's stability. Here, we present and discuss the main outputs of long-term quality assurance efforts achieved for ACSM measurements at the research station Melpitz (Germany) since 2012 onwards. In order to validate the ACSM measurements over the years and to characterize seasonal variations, nitrate, sulfate, ammonium, organic, and particle mass concentrations were systematically compared against the collocated measurements of daily offline high-volume PM1 and PM2.5 filter samples and particle number size distribution (PNSD) measurements. Mass closure analysis was made by comparing the total particle mass (PM) concentration obtained by adding the mass concentration of equivalent black carbon (eBC) from the multi-angle absorption photometer (MAAP) to the ACSM chemical composition, to that of PM1 and PM2.5 during filter weighing, as well as to the derived mass concentration of PNSD. A combination of PM1 and PM2.5 filter samples helped identifying the critical importance of the upper size cutoff of the ACSM during such exercises. The ACSM–MAAP-derived mass concentrations systematically deviated from the PM1 mass when the mass concentration of the latter represented less than 60 % of PM2.5, which was linked to the transmission efficiency of the aerodynamic lenses of the ACSM. The best correlations are obtained for sulfate (slope =0.96; R2=0.77) and total PM (slope =1.02; R2=0.90). Although, sulfate did not exhibit a seasonal dependency, total PM mass concentration revealed a small seasonal variability linked to the increase in non-water-soluble fractions. The nitrate suffers from a loss of ammonium nitrate during filter collection, and the contribution of organo-nitrate compounds to the ACSM nitrate signal make it difficult to directly compare the two methods. The contribution of m∕z 44 (f44) to the total organic mass concentration was used to convert the ACSM organic mass (OM) to organic carbon (OC) by using a similar approach as for the aerosol mass spectrometer (AMS). The resulting estimated OCACSM was compared with the measured OCPM1 (slope =0.74; R2=0.77), indicating that the f44 signal was relatively free of interferences during this period. The PM2.5 filter samples use for the ACSM data quality might suffer from a systematic bias due to a size truncation effect as well as to the presence of chemical species that cannot be detected by the ACSM in coarse mode (e.g., sodium nitrate and sodium sulfate). This may lead to a systematic underestimation of the ACSM particle mass concentration and/or a positive artifact that artificially decreases the discrepancies between the two methods. Consequently, ACSM data validation using PM2.5 filters has to be interpreted with extreme care. The particle mass closure with the PNSD was satisfying (slope =0.77; R2=0.90 over the entire period), with a slight overestimation of the mobility particle size spectrometer (MPSS)-derived mass concentration in winter. This seasonal variability was related to a change on the PNSD and a larger contribution of the supermicrometer particles in winter. This long-term analysis between the ACSM and other collocated instruments confirms the robustness of the ACSM and its suitability for long-term measurements. Particle mass closure with the PNSD is strongly recommended to ensure the stability of the ACSM. A near-real-time mass closure procedure within the entire ACTRIS–ACSM network certainly represents an optimal quality control and assurance of both warranting the quality assurance of the ACSM measurements as well as identifying cross-instrumental biases.

Atmospheric new particle formation at the research station Melpitz, Germany: connection with gaseous precursors and meteorological parameters

Abstract. This paper revisits the atmospheric new particle formation (NPF) process in the polluted Central European troposphere, focusing on the connection with gas-phase precursors and meteorological parameters. Observations were made at the research station Melpitz (former East Germany) between 2008 and 2011 involving a neutral cluster and air ion spectrometer (NAIS). Particle formation events were classified by a new automated method based on the convolution integral of particle number concentration in the diameter interval 2–20 nm. To study the relevance of gaseous sulfuric acid as a precursor for nucleation, a proxy was derived on the basis of direct measurements during a 1-month campaign in May 2008. As a major result, the number concentration of freshly produced particles correlated significantly with the concentration of sulfur dioxide as the main precursor of sulfuric acid. The condensation sink, a factor potentially inhibiting NPF events, played a subordinate role only. The same held for experimentally determined ammonia concentrations. The analysis of meteorological parameters confirmed the absolute need for solar radiation to induce NPF events and demonstrated the presence of significant turbulence during those events. Due to its tight correlation with solar radiation, however, an independent effect of turbulence for NPF could not be established. Based on the diurnal evolution of aerosol, gas-phase, and meteorological parameters near the ground, we further conclude that the particle formation process is likely to start in elevated parts of the boundary layer rather than near ground level.

Measurements of PM10 ions and trace gases with the online system MARGA at the research station Melpitz in Germany \u2013 A five-year study

An hourly quantification of inorganic water-soluble PM10 ions and corresponding trace gases was performed using the Monitor for AeRosols and Gases in ambient Air (MARGA) at the TROPOS research site in Melpitz, Germany. The data availability amounts to over 80% for the five-year measurement period from 2010 to 2014. Comparisons were performed for the evaluation of the MARGA, resulting in coefficients of determinations (slopes) of 0.91 (0.90) for the measurements against the SO2 gas monitor, 0.84 (0.88), 0.79 (1.39), 0.85 (1.20) for the ACSM NO3−, SO42− and NH4+ measurements, respectively, and 0.85 (0.65), 0.88 (0.68), 0.91 (0.83), 0.86 (0.82) for the filter measurements of Cl−, NO3−, SO42− and NH4+, respectively. A HONO comparison with a batch denuder shows large scatter (R2 = 0.41). The MARGA HNO3 is underestimated compared to a batch and coated denuder with shorter inlets (slopes of 0.16 and 0.08, respectively). Less NH3 was observed in coated denuders for high ambient concentrations. Long-time measurements show clear daily and seasonal variabilities. Potential Source Contribution Function (PSCF) analysis indicates the emission area of particulate ions Cl−, NO3−, SO42−, NH4+, K+ and gaseous SO2 to lie in eastern European countries, predominantly in wintertime. Coarse mode sea salt particles are transported from the North Sea to Melpitz. The particles at Melpitz are nearly neutralised with a mean molar ratio of 0.90 for the five-year study. A slight increase of the neutralization ratio over the last three years indicates a stronger decrease of the anthropogenically emitted NO3− and SO42− compared to NH4+.

Some insights into the condensing vapors driving new particle growth to CCN sizes on the basis of hygroscopicity measurements

Abstract. New particle formation (NPF) and growth is an important source of cloud condensation nuclei (CCN). In this study, we investigated the chemical species driving new particle growth to the CCN sizes on the basis of particle hygroscopicity measurements carried out at the research station Melpitz, Germany. Three consecutive NPF events occurred during summertime were chosen as examples to perform the study. Hygroscopicity measurements showed that the (NH4)2SO4-equivalent water-soluble fraction accounts for 20 and 16 % of 50 and 75 nm particles, respectively, during the NPF events. Numerical analysis showed that the ratios of H2SO4 condensational growth to the observed particle growth were 20 and 13 % for 50 and 75 nm newly formed particles, respectively. Aerosol mass spectrometer measurements showed that an enhanced mass fraction of sulfate and ammonium in the newly formed particles was observed when new particles grew to the sizes larger than 30 nm shortly after the particle formation period. At a later time, the secondary organic species played a key role in the particle growth. Both hygroscopicity and aerosol mass spectrometer (AMS) measurements and numerical analysis confirmed that organic compounds were major contributors driving particle growth to CCN sizes. The critical diameters at different supersaturations estimated using AMS data and κ-Köhler theory increased significantly during the later course of NPF events. This indicated that the enhanced organic mass fraction caused a reduction in CCN efficiency of newly formed particles. Our results implied that the CCN production associated with atmospheric nucleation may be overestimated if assuming that newly formed particles can serve as CCN once they grow to a fixed particle size, an assumption made in some previous studies, especially for organic-rich environments. In our study, the enhancement in CCN number concentration associated with individual NPF events were 63, 66, and 69 % for 0.1, 0.4, and 0.6 % supersaturation, respectively.

Highly Oxidized Multifunctional Organic Compounds Observed in Tropospheric Particles: A Field and Laboratory Study.

Very recent studies have reported the existence of highly oxidized multifunctional organic compounds (HOMs) with O/C ratios greater than 0.7. Because of their low vapor pressure, these compounds are often referred as extremely low-volatile organic compounds (ELVOCs), and thus, they are able to contribute significantly to organic mass in tropospheric particles. While HOMs have been successfully detected in the gas phase, their fate after uptake into particles remains unclear to date. Hence, the present study was designed to detect HOMs and related oxidation products in the particle phase and, thus, to shed light on their fate after phase transfer. To this end, aerosol chamber investigations of α-pinene ozonolysis were conducted under near environmental precursor concentrations (2.4 ppb) in a continuous flow reactor. The chemical characterization shows three classes of particle constituents: (1) intact HOMs that contain a carbonyl group, (2) particle-phase decomposition products, and (3) highly oxidized organosulfates (suggested to be addressed as HOOS). Besides chamber studies, HOM formation was also investigated during a measurement campaign conducted in summer 2013 at the TROPOS research station Melpitz. During this field campaign, gas-phase HOM formation was found to be correlated with an increase in the oxidation state of the organic aerosol.

Chemical mass balance of 300 °C non-volatile particles at the tropospheric research site Melpitz, Germany

Abstract. In the fine-particle mode (aerodynamic diameter < 1 μm) non-volatile material has been associated with black carbon (BC) and low-volatile organics and, to a lesser extent, with sea salt and mineral dust. This work analyzes non-volatile particles at the tropospheric research station Melpitz (Germany), combining experimental methods such as a mobility particle-size spectrometer (3–800 nm), a thermodenuder operating at 300 °C, a multi-angle absorption photometer (MAAP), and an aerosol mass spectrometer (AMS). The data were collected during two atmospheric field experiments in May–June 2008 as well as February–March 2009. As a basic result, we detected average non-volatile particle–volume fractions of 11 ± 3% (2008) and 17 ± 8% (2009). In both periods, BC was in close linear correlation with the non-volatile fraction, but not sufficient to quantitatively explain the non-volatile particle mass concentration. Based on the assumption that BC is not altered by the heating process, the non-volatile particle mass fraction could be explained by the sum of black carbon (47% in summer, 59% in winter) and a non-volatile organic contribution estimated as part of the low-volatility oxygenated organic aerosol (LV-OOA) (53% in summer, 41% in winter); the latter was identified from AMS data by factor analysis. Our results suggest that LV-OOA was more volatile in summer (May–June 2008) than in winter (February–March 2009) which was linked to a difference in oxidation levels (lower in summer). Although carbonaceous compounds dominated the sub-μm non-volatile particle mass fraction most of the time, a cross-sensitivity to partially volatile aerosol particles of maritime origin could be seen. These marine particles could be distinguished, however from the carbonaceous particles by a characteristic particle volume–size distribution. The paper discusses the uncertainty of the volatility measurements and outlines the possible merits of volatility analysis as part of continuous atmospheric aerosol measurements.

Seasonal and diurnal variations of particulate nitrate and organic matter at the IfT research station Melpitz

Abstract. Ammonium nitrate and several organic compounds such as dicarboxylic acids (e.g. succinic acid, glutaric acid), some Polycyclic Aromatic Hydrocarbon (PAHs) or some n-alkanes are semi-volatile. The transition of these compounds between the gas and particulate phase may significantly change the aerosol particles radiative properties, the heterogeneous chemical properties, and, naturally, the total particulate mass concentration. To better assess these time-dependent effects, three intensive field experiments were conducted in 2008–2009 at the Central European EMEP research station Melpitz (Germany) using an Aerodyne Aerosol Mass Spectrometer (AMS). Data from all seasons highlight organic matter as being the most important particulate fraction of PM1 in summer (59%) while in winter, the nitrate fraction was more prevalent (34.4%). The diurnal variation of nitrate always showed the lowest concentration during the day while its concentration increased during the night. This night increase of nitrate concentration was higher in winter (ΔNO3− = 3.6 μg m−3) than in summer (ΔNO3− = 0.7 μg m−3). The variation in particulate nitrate was inherently linked to the gas-to-particle-phase equilibrium of ammonium nitrate and the dynamics of the atmosphere during day. The results of this study suggest that during summer nights, the condensation of HNO3 and NH3 on pre-existing particles represents the most prevalent source of nitrate, whereas during winter, nighttime chemistry is the predominant source of nitrate. During the summer 2008's campaign, a clear diurnal evolution in the oxidation state of the organic matter became evident (Organic Mass to Organic Carbon ratio (OM/OC) ranging from 1.65 during night to 1.80 during day and carbon oxidation state (OSc) from −0.66 to −0.4), which could be correlated to hydroxyl radical (OH) and ozone concentrations, indicating a photochemical transformation process. In summer, the organic particulate matter seemed to be heavily influenced by regional secondary formation and transformation processes, facilitated by photochemical production processes as well as a diurnal cycling of the substances between the gas and particulate phase. In winter, these processes were obviously less pronounced (OM/OC ranging from 1.60 to 1.67 and OSc from −0.8 to −0.7), so that organic matter apparently originated mainly from aged particles and long range transport.

Changes in the production rate of secondary aerosol particles in Central Europe in view of decreasing SO<sub>2</sub> emissions between 1996 and 2006

Abstract. In anthropogenically influenced atmospheres, sulphur dioxide (SO2) is the main precursor of gaseous sulphuric acid (H2SO4), which in turn is a main precursor for atmospheric particle nucleation. As a result of socio-economic changes, East Germany has seen a dramatic decrease in anthropogenic SO2 emissions between 1989 and present, as documented by routine air quality measurements in many locations. We have attempted to evaluate the influence of changing SO2 concentrations on the frequency and intensity of new particle formation (NPF) using two different data sets (1996–1997; 2003–2006) of experimental particle number size distributions (diameter range 3–750 nm) from the atmospheric research station Melpitz near Leipzig, Germany. Between the two periods SO2 concentrations decreased by 65% on average, while the frequency of NPF events dropped by 45%. Meanwhile, the average formation rate of 3 nm particles decreased by 68% on average. The trends were statistically significant and therefore suggest a connection between the availability of anthropogenic SO2 and freshly formed new particles. In contrast to the decrease in new particle formation, we found an increase in the mean growth rate of freshly nucleated particles (+22%), suggesting that particle nucleation and subsequent growth into larger sizes are delineated with respect to their precursor species. Using three basic parameters, the condensation sink for H2SO4, the SO2 concentration, and the global radiation intensity, we were able to define the characteristic range of atmospheric conditions under which particle formation events take place at the Melpitz site. While the decrease in the concentrations and formation rates of the new particles was rather evident, no similar decrease was found with respect to the generation of cloud condensation nuclei (CCN; particle diameter >100 nm) as a result of atmospheric nucleation events. On the contrary, the production of CCN following nucleation events appears to have increased by tens of percents. Our aerosol dynamics model simulations suggest that such an increase can be caused by the increased particle growth rate.

Long-term size-segregated characterization of PM10, PM2.5, and PM1 at the IfT research station Melpitz downwind of Leipzig (Germany) using high and low-volume filter samplers

Abstract For a period of 10 years (1993–2002) daily PM10 samples were collected on quartz filters by a PM10 high-volume sampler (Sierra-Andersen). In addition, since 1995 weekly filter samples of PM10, PM2.5 and since 1999 PM1 filter samples were collected by a low-volume sampler (‘Partisol 2000’, Rupprecht and Patashnik) on Teflon filters at the IfT research station Melpitz (12°56′E, 51°32′N) located in the downwind plume of the Leipzig conurbation in central Europe. The resulting time series were compared based on weekly means (particle mass r=0.90, NO3− mass r=0.94, SO42− mass r=0.92 and NH4+ mass r=0.90) and integrated in a historical mass trend (since 1983) for Saxony. In the data (1983–1990) the total particle mass concentration (TSP) shows big scatter with a mean of about 75 μg m−3. Since the re-unification of Germany in 1990 a decrease in PM10-concentration to a mean of 20–30 μg m−3 is observed. The mass concentration of PM10 shows a decreasing trend from a yearly maximum value in 1996 (39 μg m−3) to a mean value for 1999–2002 of about 23 μg m−3. The highest values were observed just before the winter of 1997/1998. No pronounced concentration peaks were found in the following winters. Reasons are the rapid modernization of power plants and the decreasing number of coal heating systems in the Leipzig conurbation and its surroundings as well as a lack of strong inversion situations. The NO3−/SO42−-ratio shows a typical increasing trend caused by the decreasing SO42−-mass concentration in PM10 which originates in the dramatic decrease of SO2 concentrations. From the weekly low-volume samples the mass contributions of PM1, PM2.5–PM1 and PM10–PM2.5 to PM10 (100%) for 1999–2002 were about 61%, 20% and 19% for winter and 42%, 13% and 45% for summer, respectively. Most of the PM2.5 mass is PM1. During summers the weekly ratio of coarse particles (PM10–PM2.5) to fine particles (PM2.5) was higher (about 1.4) than the winter value (about 0.3). An additional impactor for PM1 at the low-volume sampler contains a quartz filter for the weekly determination of organic carbon (OC) and elemental carbon (EC) using a thermographic method. About 30% of the PM1 mass is total carbon (TC=OC+EC). The percentage of EC to TC seems to be increasing in the summer from 1999 to 2002.

Size-Resolved Aerosol Characterization for a Polluted Episode at the IfT Research Station Melpitz in Autumn 1997

Inorganic ions, organic carbon (OC), elemental carbon (EC) and a variety of organic single species in airborne particles have been determined at the research station of the Leibniz – Institut fur Tropospharenforschung (IfT) in Melpitz (Germany) in autumn 1997.

99/03222 Providing for transmission in times of scarcity: an ISO cannot do it all

For a period of 10 years (1993–2002) daily PM10 samples were collected on quartz filters by a PM10 high-volume sampler (Sierra-Andersen). In addition, since 1995 weekly filter samples of PM10, PM2.5 and since 1999 PM1 filter samples were collected by a low-volume sampler (‘Partisol 2000’, Rupprecht and Patashnik) on Teflon filters at the IfT research station Melpitz (12°56′E, 51°32′N) located in the downwind plume of the Leipzig conurbation in central Europe. The resulting time series were compared based on weekly means (particle mass r=0.90, NO3− mass r=0.94, SO42− mass r=0.92 and NH4+ mass r=0.90) and integrated in a historical mass trend (since 1983) for Saxony. In the data (1983–1990) the total particle mass concentration (TSP) shows big scatter with a mean of about 75 μg m−3. Since the re-unification of Germany in 1990 a decrease in PM10-concentration to a mean of 20–30 μg m−3 is observed. The mass concentration of PM10 shows a decreasing trend from a yearly maximum value in 1996 (39 μg m−3) to a mean value for 1999–2002 of about 23 μg m−3. The highest values were observed just before the winter of 1997/1998. No pronounced concentration peaks were found in the following winters. Reasons are the rapid modernization of power plants and the decreasing number of coal heating systems in the Leipzig conurbation and its surroundings as well as a lack of strong inversion situations. The NO3−/SO42−-ratio shows a typical increasing trend caused by the decreasing SO42−-mass concentration in PM10 which originates in the dramatic decrease of SO2 concentrations. From the weekly low-volume samples the mass contributions of PM1, PM2.5–PM1 and PM10–PM2.5 to PM10 (100%) for 1999–2002 were about 61%, 20% and 19% for winter and 42%, 13% and 45% for summer, respectively. Most of the PM2.5 mass is PM1. During summers the weekly ratio of coarse particles (PM10–PM2.5) to fine particles (PM2.5) was higher (about 1.4) than the winter value (about 0.3). An additional impactor for PM1 at the low-volume sampler contains a quartz filter for the weekly determination of organic carbon (OC) and elemental carbon (EC) using a thermographic method. About 30% of the PM1 mass is total carbon (TC=OC+EC). The percentage of EC to TC seems to be increasing in the summer from 1999 to 2002.

Main particulate matter components in Saxony (Germany)

Aerosol filter samples have been collected nearby the industrialised basin of Leipzig in Saxony (Germany) at the research station Melpitz of the Institut für Troposphärenforschung e.V. (IfT). Time series (1992-1998) and a three year comparison (1995-1997) of two different aerosol filter sampling systems, the Sierra-Andersen-PM 10 high volume sampler (daily sample, PM 10 inlet) and the Rupprecht and Patashnik Co. Inc. Model Partisol 2000 (weekly sample, PM 10 and PM 2.5 inlet) are presented and discussed. The comparison of the different sampling systems and strategies yields small differences between the daily and weekly samples for mass and different ions, which may be influenced by sampling duration and flow rates. A general trend of change in aerosol composition was observed: Soot and Sulphate concentrations decreased whereas Nitrate and Ammonium concentrations increased. During summers the mass of coarse particles is higher than in other seasons. One reason could be found in the occurrence of longer periods of dry ground surfaces enabling reemission of crustal and biological material. The time series have been integrated in a longer historical aerosol mass trend for Saxony and do show a good agreement. Since 1990 a significant downward trend in gravimetric mass concentration was found.

Determination of aldehydes and ketones in the atmosphere — A comparative long time study at an urban and a rural site in Eastern Germany

Subsequent to the political changes in Eastern Germany, environmental changes were the subject of the scientific research project SANA. Until 1990, the area of Leipzig was the most polluted region in Germany. Variabilities and commonalities of the longest measurement series concerning carbonyl compounds in Central Europe are presented. Yearly and diurnal variations of main carbonyl compounds from Leipzig and the rural research station Melpitz (both in Saxony, Germany) are discussed. Anthropogenic influences (traffic, industry and households) and winter inversion periods are estimated. The broad variability of carbonyl concentrations in the air is demonstrated.