Atmosphärische gasförmige Vorläufer von Aerosol und Ozon: Messungen mit CIMS-Methoden auf einem Flugzeug und am Boden

Die vorliegende Arbeit zielt auf Messungen von atmosphärischen Spurengasen, die einen Einfluss auf die Bildung von Ozon und Aerosol-Teilchen haben. Es wurden Flugzeug- und Bodenmessungen mit zwei unterschiedlichen Arten von Massenspektrometern in Höhen von 0-12km durchgeführt. Diese Messungen mit (Ultra-)CIMS (= Chemische-Ionisations-Massenspektrometrie) beinhalteten besonders die Spurengase SO2, H2SO4, (CH3)2CO (Aceton) und CH3OH (Methanol). Wandverluste und Wasserdampf-Querempfindlichkeiten in der Sammelleitung wurden mit Hilfe von Kalibrationen und Berechnungen berücksichtigt. Die Höhenverteilung von Schwefeldioxid, das ein Vorläufer von gasförmiger Schwefelsäure ist, wurde näher untersucht. Es wurden Hinweise gefunden, dass sowohl Aceton als auch Methanol im gesamten betrachteten Höhenbereich vorhanden sind. Insbesondere wurde ein interkontinentaler Transport von Aceton beobachtet. Aceton und Methanol sind wichtige Vorläufer von HOx(=OH,HO2) und Ozon in der oberen Troposphäre und untersten Stratosphäre. In der planetaren Grenzschicht wurde ein Tagesgang der Konzentrationen gasförmiger Schwefelsäure beobachtet, wobei mittags die höchsten Werte vorkommen, die gelegentlich eine Partikelneubildung durch bimolekulare homogene Nukleation ermöglichen

Detection of 133^{133}Xe from the Fukushima nuclear power plant in the upper troposphere above Germany

After the accident in the Japanese Fukushima Dai-ichi nuclear power plant in March 2011 large amounts of radioactivity were released and distributed in the atmosphere. Among them were also radioactive noble gas isotopes which can be used as tracers to test global atmospheric circulation models. This work presents unique measurements of the radionuclide $^{133}$Xe from Fukushima in the upper troposphere above Germany. The measurements involve air sampling in a research jet aircraft followed by chromatographic xenon extraction and ultra-low background gas counting with miniaturized proportional counters. With this technique a detection limit of the order of 100 $^{133}$Xe atoms in litre-scale air samples (corresponding to about 100 mBq/m$^3$) is achievable. Our results provide proof that the $^{133}$Xe-rich ground level air layer from Fukushima was lifted up to the tropopause and distributed hemispherically. Moreover, comparisons with ground level air measurements indicate that the arrival of the radioactive plume at high altitude over Germany occurred several days before the ground level plume.Comment: 8 pages, 5 figure

Emissions of sulphur dioxide (SO2) from coal-fired power plants in Serbia and Bosnia-Herzegovina: First attempts of a validation of TROPOMI satellite products with airborne in situ measurements

The Western Balkan region is known for emitting alarmingly high sulphur dioxide amounts from coal-fired power plants. Though a number of environmental regulations have been introduced in recent years (e.g. desulphurisation installations, construction of modern power plants), the pollution burden is still much higher than recommended by the authorities. A number of different montoring systems are required to observe the growing pollution situation in the Western Balkan region, partly caused by a high energy demand from outside (e.g. Western Europe)

Results from the CERN pilot CLOUD experiment

During a 4-week run in October–November 2006, a pilot experiment was performed at the CERN Proton Synchrotron in preparation for the Cosmics Leaving OUtdoor Droplets (CLOUD) experiment, whose aim is to study the possible influence of cosmic rays on clouds. The purpose of the pilot experiment was firstly to carry out exploratory measurements of the effect of ionising particle radiation on aerosol formation from trace H2SO4 vapour and secondly to provide technical input for the CLOUD design. A total of 44 nucleation bursts were produced and recorded, with formation rates of particles above the 3 nm detection threshold of between 0.1 and 100 cm -3 s -1, and growth rates between 2 and 37 nm h -1. The corresponding H2O concentrations were typically around 106 cm -3 or less. The experimentally-measured formation rates and htwosofour concentrations are comparable to those found in the atmosphere, supporting the idea that sulphuric acid is involved in the nucleation of atmospheric aerosols. However, sulphuric acid alone is not able to explain the observed rapid growth rates, which suggests the presence of additional trace vapours in the aerosol chamber, whose identity is unknown. By analysing the charged fraction, a few of the aerosol bursts appear to have a contribution from ion-induced nucleation and ion-ion recombination to form neutral clusters. Some indications were also found for the accelerator beam timing and intensity to influence the aerosol particle formation rate at the highest experimental SO2 concentrations of 6 ppb, although none was found at lower concentrations. Overall, the exploratory measurements provide suggestive evidence for ion-induced nucleation or ion-ion recombination as sources of aerosol particles. However in order to quantify the conditions under which ion processes become significant, improvements are needed in controlling the experimental variables and in the reproducibility of the experiments. Finally, concerning technical aspects, the most important lessons for the CLOUD design include the stringent requirement of internal cleanliness of the aerosol chamber, as well as maintenance of extremely stable temperatures (variations below 0.1 °C

An aircraft-borne chemical ionization – ion trap mass spectrometer (CI-ITMS) for fast PAN and PPN measurements

An airborne chemical ionization ion trap mass spectrometer instrument (CI-ITMS) has been developed for tropospheric and stratospheric fast in-situ measurements of PAN (peroxyacetyl nitrate) and PPN (peroxypropionyl nitrate). The first scientific deployment of the FASTPEX instrument (FASTPEX = Fast Measurement of Peroxyacyl nitrates) took place in the Arctic during 18 missions aboard the DLR research aircraft Falcon, within the framework of the POLARCAT-GRACE campaign in the summer of 2008. The FASTPEX instrument is described and characteristic properties of the employed ion trap mass spectrometer are discussed. Atmospheric data obtained at altitudes of up to ~12 km are presented, from the boundary layer to the lowermost stratosphere. Data were sampled with a time resolution of 2 s and a 2σ detection limit of 25 pmol mol−1. An isotopically labelled standard was used for a permanent online calibration. For this reason the accuracy of the PAN measurements is better than ±10% for mixing ratios greater than 200 pmol mol−1. PAN mixing ratios in the summer Arctic troposphere were in the order of a few hundred pmol mol−1 and generally correlated well with CO. In the Arctic boundary layer and lowermost stratosphere smaller PAN mixing ratios were observed due to a combination of missing local sources of PAN precursor gases and efficient removal processes (thermolysis/photolysis). PPN, the second most abundant PAN homologue, was measured simultanously. Observed PPN/PAN ratios range between ~0.03 and 0.

Tropospheric SO₂ Distributions during SCOUT-O3 Tropical – Main Features and Comparison to other Campaigns

During SCOUT-O3 Tropical in November 2005 detailed vertical distributions of the SO2 mixing ratio in the troposphere were measured with the DLR research aircraft Falcon. 9 flights from Darwin, Australia and 14 transfer flights between Germany and Australia have been performed. The measurement technique employed was chemical ionization with ion trap massspectrometric detection. Observed vertical SO2 profiles will be presented and compared to SO2 observations in tropical South America during TROCCINOX 2005 and to observations in Europe during INTEX-B 2006. The origin of the air masses sampled will be discussed using back-trajectory analysis for selected cases

An ion trap CIMS instrument for combined measurements of atmospheric OH and H2SO4: First test measurements above and inside the planetary boundary layer

Gaseous sulfuric acid (GSA) plays an important role in atmospheric secondary aerosol formation. To quantify its contribution to these processes long-term measurements of GSA using a very sensitive detection method are required. OH is the most important oxidant in the atmosphere and oxidizes, e.g., SO2. A powerful detection method is chemical ionization mass spectrometry (CIMS). We have built a novel CIMS instrument composed of an ion trap mass spectrometer (ITMS) and a selective ion source suitable to measure gaseous H2SO4 and OH and to do fragmentation studies. The probe air inlet and sampling line were optimized to minimize wall losses of H2SO4 and OH. An ion source was developed to minimize artificial signals and to create reagent ions ((HNO3)h(H2O)n) which react highly selectively with GSA. An H2SO4/OH calibration source based on water vapor photolysis was developed to overcome uncertainties in remaining wall losses, ion residence time, reaction rate coefficient and mass discrimination. Field measurements of GSA in the planetary boundary layer (several weeks at northern and middle latitudes) and high-altitude mountain-site measurements of GSA and OH were carried out. The ITMS instrument offers a detection limit as low as 1 × 10^5 molecules per cm^3 and a time resolution of about 2 min

Flugzeugmessungen von atmosphärischem SO2 während SCOUT.

Während der SCOUT-Kampagne wurden die bisher umfangreichsten modernen Messungen des atmosphärischen Spurengases SO2 mit einem neuen flugzeuggetragenen Ionen-Molekül-Reaktions-Massenspektrometer durchgeführt. Während der Transferflüge (Deutschland-Australien- Deutschland) wurde permanent SO2 gemessen. In Nordaustralien wurden mehrere lokale Messflüge durchgeführt. Alle Messungen wurden von einer permanenten SO2-Eichung mit isotopisch markiertem SO2 begleitet

A novel rocket-borne ion mass spectrometer with large mass range: instrument description and first-flight results

In this paper we describe the instrument ROMARA and show data from the first flight on a research rocket. On the way through the atmosphere, the instrument detects positive and negative, natural occurring ions before returning back to ground. ROMARA was successfully launched together with other instruments into a special radar echo. We detected typical, light ions of positive and negative charge and heavy negative ions, but no heavy positive ions