Author
Katrin Fuhrer
Other affiliations: Texas A&M University, University of Colorado Boulder, RWTH Aachen University
Bio: Katrin Fuhrer is an academic researcher from University of Bern. The author has contributed to research in topics: Mass spectrometry & Ice core. The author has an hindex of 27, co-authored 38 publications receiving 4405 citations. Previous affiliations of Katrin Fuhrer include Texas A&M University & University of Colorado Boulder.
Papers
More filters
••
TL;DR: The development of a new high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) is reported, which allows the direct separation of most ions from inorganic and organic species at the same nominal m/z, and the quantification of several types of organic fragments.
Abstract: The development of a new high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) is reported. The high-resolution capabilities of this instrument allow the direct separation of most ions from inorganic and organic species at the same nominal m/z, the quantification of several types of organic fragments (CxHy, CxHyOz, CxHyNp, CxHyOzNp), and the direct identification of organic nitrogen and organosulfur content. This real-time instrument is field-deployable, and its high time resolution (0.5 Hz has been demonstrated) makes it well-suited for studies in which time resolution is critical, such as aircraft studies. The instrument has two ion optical modes: a single-reflection configuration offers higher sensitivity and lower resolving power (up to ∼2100 at m/z 200), and a two-reflectron configuration yields higher resolving power (up to ∼4300 at m/z 200) with lower sensitivity. The instrument also allows the determination of the size distributions of all ions. One-minute detection limits for subm...
1,818 citations
••
TL;DR: In this article, the authors report the development and first field deployment of a new version of the AMS, which is capable of measuring non-refractory aerosol mass concentrations, chemically speciated mass distributions and single particle information.
Abstract: We report the development and first field deployment of a new version of the Aerosol Mass Spectrometer (AMS), which is capable of measuring non-refractory aerosol mass concentrations, chemically speciated mass distributions and single particle information. The instrument was constructed by interfacing the well-characterized Aerodyne AMS vacuum system, particle focusing, sizing, and evaporation/ionization components, with a compact TOFWERK orthogonal acceleration reflectron time-of-flight mass spectrometer. In this time-of-flight aerosol mass spectrometer (TOF-AMS) aerosol particles are focused by an aerodynamic lens assembly as a narrow beam into the vacuum chamber. Non-refractory particle components flash-vaporize after impaction onto the vaporizer and are ionized by electron impact. The ions are continuously guided into the source region of the time-of-flight mass spectrometer, where ions are extracted into the TOF section at a repetition rate of 83.3 kHz. Each extraction generates a complete mass spect...
663 citations
••
TL;DR: A Northern Hemisphere deuterium excess profile covering one climatic cycle is presented, constructed with the use of δ18O and δD Greenland Ice Core Project (GRIP) records, to demonstrate the imprint of obliquity in the site-to-source temperature gradient at orbital scale.
Abstract: The Northern Hemisphere hydrological cycle is a key factor coupling ice sheets, ocean circulation, and polar amplification of climate change. Here we present a Northern Hemisphere deuterium excess profile covering one climatic cycle, constructed with the use of δ 18 O and δD Greenland Ice Core Project (GRIP) records. Past changes in Greenland source and site temperatures are quantified with precipitation seasonality taken into account. The imprint of obliquity is evidenced in the site-to-source temperature gradient at orbital scale. At the millennial time scale, GRIP source temperature changes reflect southward shifts of the geographical locations of moisture sources during cold events, and these rapid shifts are associated with large-scale changes in atmospheric circulation.
304 citations
••
TL;DR: A new deep core drilling operation started in 1990 in central Greenland and in 1992 reached the bottom at a depth of 3028 m.b.p. surface, corresponding to the time interval between 8000 and 38,000 years B.P. as mentioned in this paper.
170 citations
••
TL;DR: The ability to separate peptide mixtures, e.g., tryptic digest of a protein, is illustrated and compared to results obtained on a high-vacuum time-of-flight instrument.
Abstract: A new ion mobility/time-of-flight mass spectrometer employing a high-pressure MALDI source has been designed and tested. The prototype instrument operates at a source/drift cell pressure of 1−10 Torr helium, resulting in a mobility resolution of ∼25. A small time-of-flight mass spectrometer (20 cm) with a mass resolution of up to 200 has been attached to the drift cell to identify (in terms of mass-to-charge ratio) the separated ions. A simple tripeptide mixture has been separated in the drift tube and mass identified as singly protonated species. The ability to separate peptide mixtures, e.g., tryptic digest of a protein, is illustrated and compared to results obtained on a high-vacuum time-of-flight instrument.
159 citations
Cited by
More filters
••
TL;DR: The results suggest that, in addition to mitigating primary particulate emissions, reducing the emissions of secondary aerosol precursors from fossil fuel combustion and biomass burning is likely to be important for controlling China’s PM2.5 levels and for reducing the environmental, economic and health impacts resulting from particulate pollution.
Abstract: Rapid industrialization and urbanization in developing countries has led to an increase in air pollution, along a similar trajectory to that previously experienced by the developed nations. In China, particulate pollution is a serious environmental problem that is influencing air quality, regional and global climates, and human health. In response to the extremely severe and persistent haze pollution experienced by about 800 million people during the first quarter of 2013 (refs 4, 5), the Chinese State Council announced its aim to reduce concentrations of PM2.5 (particulate matter with an aerodynamic diameter less than 2.5 micrometres) by up to 25 per cent relative to 2012 levels by 2017 (ref. 6). Such efforts however require elucidation of the factors governing the abundance and composition of PM2.5, which remain poorly constrained in China. Here we combine a comprehensive set of novel and state-of-the-art offline analytical approaches and statistical techniques to investigate the chemical nature and sources of particulate matter at urban locations in Beijing, Shanghai, Guangzhou and Xi'an during January 2013. We find that the severe haze pollution event was driven to a large extent by secondary aerosol formation, which contributed 30-77 per cent and 44-71 per cent (average for all four cities) of PM2.5 and of organic aerosol, respectively. On average, the contribution of secondary organic aerosol (SOA) and secondary inorganic aerosol (SIA) are found to be of similar importance (SOA/SIA ratios range from 0.6 to 1.4). Our results suggest that, in addition to mitigating primary particulate emissions, reducing the emissions of secondary aerosol precursors from, for example, fossil fuel combustion and biomass burning is likely to be important for controlling China's PM2.5 levels and for reducing the environmental, economic and health impacts resulting from particulate pollution.
3,372 citations
••
University of Gothenburg1, University College Cork2, Paul Scherrer Institute3, Weizmann Institute of Science4, Chalmers University of Technology5, Norwegian Meteorological Institute6, University of Antwerp7, Carnegie Mellon University8, University of Lyon9, Centre national de la recherche scientifique10, University of California, Berkeley11, University of York12, Leibniz Institute for Neurobiology13, University of Mainz14, University of Florida15, University of Colorado Boulder16, Forschungszentrum Jülich17, Ghent University18, University of Manchester19, Aix-Marseille University20, California Institute of Technology21
TL;DR: In this article, an overview of the atmospheric degradation mechanisms for SOA precursors, gas-particle partitioning theory and analytical techniques used to determine the chemical composition of SOA is presented.
Abstract: Secondary organic aerosol (SOA) accounts for a significant fraction of ambient tropospheric aerosol and a detailed knowledge of the formation, properties and transformation of SOA is therefore required to evaluate its impact on atmospheric processes, climate and human health. The chemical and physical processes associated with SOA formation are complex and varied, and, despite considerable progress in recent years, a quantitative and predictive understanding of SOA formation does not exist and therefore represents a major research challenge in atmospheric science. This review begins with an update on the current state of knowledge on the global SOA budget and is followed by an overview of the atmospheric degradation mechanisms for SOA precursors, gas-particle partitioning theory and the analytical techniques used to determine the chemical composition of SOA. A survey of recent laboratory, field and modeling studies is also presented. The following topical and emerging issues are highlighted and discussed in detail: molecular characterization of biogenic SOA constituents, condensed phase reactions and oligomerization, the interaction of atmospheric organic components with sulfuric acid, the chemical and photochemical processing of organics in the atmospheric aqueous phase, aerosol formation from real plant emissions, interaction of atmospheric organic components with water, thermodynamics and mixtures in atmospheric models. Finally, the major challenges ahead in laboratory, field and modeling studies of SOA are discussed and recommendations for future research directions are proposed.
3,324 citations
••
TL;DR: The connections between time series analysis and nonlinear dynamics, discuss signal-to-noise enhancement, and present some of the novel methods for spectral analysis are described.
Abstract: [1] The analysis of univariate or multivariate time series provides crucial information to describe, understand, and predict climatic variability. The discovery and implementation of a number of novel methods for extracting useful information from time series has recently revitalized this classical field of study. Considerable progress has also been made in interpreting the information so obtained in terms of dynamical systems theory. In this review we describe the connections between time series analysis and nonlinear dynamics, discuss signal-to-noise enhancement, and present some of the novel methods for spectral analysis. The various steps, as well as the advantages and disadvantages of these methods, are illustrated by their application to an important climatic time series, the Southern Oscillation Index. This index captures major features of interannual climate variability and is used extensively in its prediction. Regional and global sea surface temperature data sets are used to illustrate multivariate spectral methods. Open questions and further prospects conclude the review.
2,116 citations
••
TL;DR: The development of a new high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) is reported, which allows the direct separation of most ions from inorganic and organic species at the same nominal m/z, and the quantification of several types of organic fragments.
Abstract: The development of a new high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) is reported. The high-resolution capabilities of this instrument allow the direct separation of most ions from inorganic and organic species at the same nominal m/z, the quantification of several types of organic fragments (CxHy, CxHyOz, CxHyNp, CxHyOzNp), and the direct identification of organic nitrogen and organosulfur content. This real-time instrument is field-deployable, and its high time resolution (0.5 Hz has been demonstrated) makes it well-suited for studies in which time resolution is critical, such as aircraft studies. The instrument has two ion optical modes: a single-reflection configuration offers higher sensitivity and lower resolving power (up to ∼2100 at m/z 200), and a two-reflectron configuration yields higher resolving power (up to ∼4300 at m/z 200) with lower sensitivity. The instrument also allows the determination of the size distributions of all ions. One-minute detection limits for subm...
1,818 citations
••
TL;DR: In this paper, a new common stratigraphic timescale for the North Greenland Ice Core Project (NGRIP) and GRIP ice cores is presented, which covers the period 7.9-14.8 kyr before present and includes the Bolling, Allerod, Younger Dryas, and early Holocene periods.
Abstract: [1] We present a new common stratigraphic timescale for the North Greenland Ice Core Project (NGRIP) and GRIP ice cores. The timescale covers the period 7.9–14.8 kyr before present and includes the Bolling, Allerod, Younger Dryas, and early Holocene periods. We use a combination of new and previously published data, the most prominent being new high-resolution Continuous Flow Analysis (CFA) impurity records from the NGRIP ice core. Several investigators have identified and counted annual layers using a multiparameter approach, and the maximum counting error is estimated to be up to 2% in the Holocene part and about 3% for the older parts. These counting error estimates reflect the number of annual layers that were hard to interpret, but not a possible bias in the set of rules used for annual layer identification. As the GRIP and NGRIP ice cores are not optimal for annual layer counting in the middle and late Holocene, the timescale is tied to a prominent volcanic event inside the 8.2 kyr cold event, recently dated in the DYE-3 ice core to 8236 years before A. D. 2000 (b2k) with a maximum counting error of 47 years. The new timescale dates the Younger Dryas-Preboreal transition to 11,703 b2k, which is 100–150 years older than according to the present GRIP and NGRIP timescales. The age of the transition matches the GISP2 timescale within a few years, but viewed over the entire 7.9–14.8 kyr section, there are significant differences between the new timescale and the GISP2 timescale. The transition from the glacial into the Bolling interstadial is dated to 14,692 b2k. The presented timescale is a part of a new Greenland ice core chronology common to the DYE-3, GRIP, and NGRIP ice cores, named the Greenland Ice Core Chronology 2005 (GICC05). The annual layer thicknesses are observed to be log-normally distributed with good approximation, and compared to the early Holocene, the mean accumulation rates in the Younger Dryas and Bolling periods are found to be 47 ± 2% and 88 ± 2%, respectively.
1,789 citations