scholarly journals Chemical composition of free tropospheric aerosol for PM1 and coarse mode at the high alpine site Jungfraujoch

2008 ◽  
Vol 8 (2) ◽  
pp. 407-423 ◽  
Author(s):  
J. Cozic ◽  
B. Verheggen ◽  
E. Weingartner ◽  
J. Crosier ◽  
K. N. Bower ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Monitoring Program ◽  
Saharan Dust ◽  
Research Station ◽  
Aerosol Mass ◽  
Coarse Mode ◽  
Tropospheric Aerosol ◽  
Dust Events ◽  
Alpine Research ◽  
Mass Concentrations

Abstract. The chemical composition of submicron (fine mode) and supermicron (coarse mode) aerosol particles has been investigated at the Jungfraujoch high alpine research station (3580 m a.s.l., Switzerland) as part of the GAW aerosol monitoring program since 1999. A clear seasonality was observed for all major components throughout the period with low concentrations in winter (predominantly free tropospheric aerosol) and higher concentrations in summer (enhanced vertical transport of boundary layer pollutants). In addition, mass closure was attempted during intensive campaigns in March 2004, February–March 2005 and August 2005. Ionic, carbonaceous and non-refractory components of the aerosol were quantified as well as the PM1 and coarse mode total aerosol mass concentrations. A relatively low conversion factor of 1.8 for organic carbon (OC) to particulate organic matter (OM) was found in winter (February–March 2005). Organics, sulfate, ammonium, and nitrate were the major components of the fine aerosol fraction that were identified, while calcium and nitrate were the only two measured components contributing to the coarse mode. The aerosol mass concentrations for fine and coarse mode aerosol measured during the intensive campaigns were not typical of the long-term seasonality due largely to dynamical differences. Average fine and coarse mode concentrations during the intensive field campaigns were 1.7 μg m−3 and 2.4 μg m−3 in winter and 2.5 μg m−3 and 2.0 μg m−3 in summer, respectively. The mass balance of aerosols showed higher contributions of calcium and nitrate in the coarse mode during Saharan dust events (SDE) than without SDE.

scholarly journals Chemical composition of free tropospheric aerosol for PM1 and coarse mode at the high alpine site Jungfraujoch

2007 ◽  
Vol 7 (4) ◽  
pp. 12145-12184 ◽  
Author(s):  
J. Cozic ◽  
B. Verheggen ◽  
E. Weingartner ◽  
J. Crosier ◽  
K. Bower ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Monitoring Program ◽  
Saharan Dust ◽  
Research Station ◽  
Aerosol Mass ◽  
Coarse Mode ◽  
Tropospheric Aerosol ◽  
Dust Events ◽  
Alpine Research ◽  
Mass Concentrations

Abstract. The chemical composition of submicron (fine mode) and supermicron (coarse mode) aerosol particles has been investigated since 1999 within the GAW aerosol monitoring program at the high alpine research station Jungfraujoch (3580 m a.s.l., Switzerland). Clear seasonality was observed for all major components in the last 9 years with low concentrations in winter (predominantly free tropospheric aerosol) and higher concentrations in summer (enhanced vertical transport of boundary layer pollutants). In addition, mass closure was attempted during intensive experiments in March 2004, February–March 2005 and August 2005. Ionic, carbonaceous and refractory components of the aerosol were quantified as well as the PM1 and coarse mode total aerosol mass concentrations. A relatively low conversion factor of 1.8 for organic carbon (OC) to particulate organic matter (OM) in winter (February–March 2005) was found. Organics, sulfate, ammonium, and nitrate were the major identified components of the fine aerosol fraction, while calcium and nitrate were the two major measured components in the coarse mode. The aerosol mass concentrations for fine and coarse mode aerosol during the intensive campaigns were not typical of the long term seasonality due largely to dynamical differences. Average fine and coarse mode concentrations during the intensive field campaigns were 1.7 μg m−3 and 2.4 μg m−3 in winter and 2.5 μg m−3 and 2.0 μg m−3 in summer, respectively. The mass balance of aerosols showed higher contributions of calcium and nitrate in the coarse mode during Saharan dust events (SDE) than without SDE.

scholarly journals Hygroscopicity of the submicrometer aerosol at the high-alpine site Jungfraujoch, 3580 m a.s.l., Switzerland

2008 ◽  
Vol 8 (18) ◽  
pp. 5715-5729 ◽  
Author(s):  
S. Sjogren ◽  
M. Gysel ◽  
E. Weingartner ◽  
M. R. Alfarra ◽  
J. Duplissy ◽  
...  
Keyword(s):  
Growth Factors ◽  
Particle Diameter ◽  
Phase Changes ◽  
Saharan Dust ◽  
Research Station ◽  
Hygroscopic Growth ◽  
Frequency Distributions ◽  
Dust Events ◽  
Alpine Research ◽  
Air Mass Types

Abstract. Data from measurements of hygroscopic growth of submicrometer aerosol with a hygroscopicity tandem differential mobility analyzer (HTDMA) during four campaigns at the high alpine research station Jungfraujoch, Switzerland, are presented. The campaigns took place during the years 2000, 2002, 2004 and 2005, each lasting approximately one month. Hygroscopic growth factors (GF, i.e. the relative change in particle diameter from dry diameter, D0, to diameter measured at higher relative humidity, RH) are presented for three distinct air mass types, namely for: 1) free tropospheric winter conditions, 2) planetary boundary layer influenced air masses (during a summer period) and 3) Saharan dust events (SDE). The GF values at 85% RH (D0=100 nm) were 1.40±0.11 and 1.29±0.08 for the first two situations while for SDE a bimodal GF distribution was often found. No phase changes were observed when the RH was varied between 10–90%, and the continuous water uptake could be well described with a single-parameter empirical model. The frequency distributions of the average hygroscopic growth factors and the width of the retrieved growth factor distributions (indicating whether the aerosol is internally or externally mixed) are presented, which can be used for modeling purposes. Measurements of size resolved chemical composition were performed with an aerosol mass spectrometer in parallel to the GF measurements. This made it possible to estimate the apparent ensemble mean GF of the organics (GForg) using inverse ZSR (Zdanovskii-Stokes-Robinson) modeling. GForg was found to be ~1.20 at aw=0.85, which is at the upper end of previous laboratory and field data though still in agreement with the highly aged and oxidized nature of the Jungfraujoch aerosol.

scholarly journals Ice nuclei properties within a Saharan dust event at the Jungfraujoch in the Swiss Alps

2011 ◽  
Vol 11 (10) ◽  
pp. 4725-4738 ◽  
Author(s):  
C. Chou ◽  
O. Stetzer ◽  
E. Weingartner ◽  
Z. Jurányi ◽  
Z. A. Kanji ◽  
...  
Keyword(s):  
Correlation Factor ◽  
Number Concentration ◽  
Swiss Alps ◽  
Saharan Dust ◽  
Research Station ◽  
Dust Event ◽  
Ice Nuclei ◽  
Carbon Mass ◽  
Dust Events ◽  
Alpine Research

Abstract. The new portable ice nucleation chamber (PINC) developed by the Institute for Atmospheric and Climate Sciences of ETH Zurich was operated during two measurement campaigns at the high alpine research station Jungfraujoch situated at 3580 m a.s.l, in March and June 2009. During this time of the year, a high probability of Saharan dust events (SDE) at the Jungfraujoch has been observed. We used an impactor with a cutoff size of 1 μm aerodynamic diameter and operated the system at −31 °C and relative humidities of 127 % and 91 % with respect to ice and water, respectively. Investigation of the ambient number concentration of ice nuclei (IN) in the deposition nucleation mode and during a SDE in the free troposphere is reported. The results discussed in this paper are the first continuous IN measurements over a period of several days at the Jungfraujoch. The average IN concentration found during the campaign in March was 8 particles per liter whereas during the campaign in June, the average number concentration was higher up to 14 particles per liter. Two SDEs were detected on 15 and 16 June 2009. Our measurements show that the SDEs had IN number concentration up to several hundreds per liter. We found the best correlation between the number concentration of the larger particle fraction measured by an optical particle counter and the IN number concentration during a Saharan dust event. This correlation factor is higher for particles larger than 0.5 μm meaning that a higher concentration of larger particles induced higher IN number concentration. No correlation could be found between the black carbon mass concentration and the variations in IN number concentration.

scholarly journals Hygroscopicity of the submicrometer aerosol at the high-alpine site Jungfraujoch, 3580 m a.s.l., Switzerland

2007 ◽  
Vol 7 (5) ◽  
pp. 13699-13732 ◽  
Author(s):  
S. Sjogren ◽  
M. Gysel ◽  
E. Weingartner ◽  
M. R. Alfarra ◽  
J. Duplissy ◽  
...  
Keyword(s):  
Growth Factors ◽  
Particle Diameter ◽  
Phase Changes ◽  
Saharan Dust ◽  
Research Station ◽  
Hygroscopic Growth ◽  
Frequency Distributions ◽  
Dust Events ◽  
Alpine Research ◽  
Air Mass Types

Abstract. Data from measurements of hygroscopic growth of submicrometer aerosol with a hygroscopicity tandem differential mobility analyzer (HTDMA) during four campaigns at the high alpine research station Jungfraujoch, Switzerland, are presented. The campaigns took place during the years 2000, 2002, 2004 and 2005, each lasting approximately one month. In parallel, size resolved chemical composition measurements with an aerosol mass spectrometer were performed. A hygroscopic closure was done with the composition data using the Zdanovskii-Stokes-Robinson relation. In general, a good agreement between measured and modeled data was found, with some discrepancies caused by instrumental noise at low aerosol loadings. Hygroscopic growth factors (GF, i.e. the relative change in particle diameter from dry diameter, D0, to diameter measured at higher relative humidity, RH) are presented for three distinct air mass types, namely for: 1) free tropospheric winter conditions, 2) planetary boundary layer influenced air masses (during a summer period) and 3) Saharan dust events (SDE). The GF values at 85% RH (D0=100 nm) were 1.40±0.11 and 1.29±0.08 for the first two situations while for SDE a bimodal GF distribution was often found. No phase changes were observed when the RH was varied between 10–90%, and the continuous water uptake could be well described with a single-parameter empirical model. The frequency distributions of the average hygroscopic growth factors and the width of the retrieved growth factor distributions (indicating whether the aerosol is internally or externally mixed) are presented, which can be used for modeling purposes.

scholarly journals Ice nuclei properties within a Saharan Dust Event at the Jungfraujoch

2010 ◽  
Vol 10 (10) ◽  
pp. 23705-23738
Author(s):  
C. Chou ◽  
O. Stetzer ◽  
E. Weingartner ◽  
Z. Jurányi ◽  
Z. A. Kanji ◽  
...  
Keyword(s):  
Correlation Factor ◽  
Number Concentration ◽  
Saharan Dust ◽  
Research Station ◽  
Dust Event ◽  
Ice Nuclei ◽  
Carbon Mass ◽  
Dust Events ◽  
Alpine Research ◽  
Mixed Phase Clouds

Abstract. The new portable ice nucleation chamber (PINC) developed by the Institute for Atmospheric and Climate Sciences of ETH Zurich was operated during two campaigns PINC II and III at the high alpine research station Jungfraujoch situated at 3580 m a.s.l., in March and June 2009, respectively. During this time of the year, a high probability of Saharan Dust Events (SDE) at the Jungfraujoch has been observed. We used an impactor with a cutoff size of 1 μm aerodynamic diameter and operated the system at −31 °C and relative humidities of 127% and 91% with respect to ice and water, respectively in order to investigate the contribution of deposition freezing to mixed-phase clouds and also to look at the number concentration of ice nuclei (IN) during a SDE. The average IN concentration during PINC II was 8 particles per liter whereas during PINC III, the average number concentration was higher up to 14 particles per liter. Two SDEs were detected on 15 and 16 June 2009. Our measurements show that the SDEs had IN number concentration up to several hundreds per liter. We found the best correlation between the number concentration of the larger particle fraction measured by an optical particle counter and the IN number concentration during a Saharan Dust Event. This correlation factor is higher for particles larger than 0.5 μm meaning that a higher concentration of larger particles induced higher IN number concentration. No correlation could be found between the black carbon mass concentration and the variations in IN number concentration.

scholarly journals Size-segregated aerosol mass closure and chemical composition in Monte Cimone (I) during MINATROC

2004 ◽  
Vol 4 (4) ◽  
pp. 889-902 ◽  
Author(s):  
J.-P. Putaud ◽  
R. Van Dingenen ◽  
A. Dell'Acqua ◽  
F. Raes ◽  
E. Matta ◽  
...  
Keyword(s):  
Particle Size ◽  
Chemical Composition ◽  
Mass Concentration ◽  
Saharan Dust ◽  
Dust Particles ◽  
Chemical Analyses ◽  
Aerosol Mass ◽  
Aerosol Mass Concentration ◽  
Random Uncertainties ◽  
Mass Concentrations

Abstract. Physical and chemical characterizations of the atmospheric aerosol were carried out at Mt. Cimone (Italy) during the 4 June-4 July 2000 period. Particle size distributions in the size range 6nm-10µm were measured with a differential mobility analyzer (DMA) and an optical particle counter (OPC). Size-segregated aerosol was sampled using a 6-stage low pressure impactor. Aerosol samples were submitted to gravimetric and chemical analyses. Ionic, carbonaceous and refractory components of the aerosol were quantified. We compared the sub- and superµm aerosol mass concentrations determined by gravimetric measurements (mGM), chemical analyses (mmCA), and by converting particle size distribution to aerosol mass concentrations (mmSD). Mean random uncertainties associated with the determination of mmGM, mmCA, and mmSD were assessed. The three estimates of the sub-µm aerosol mass concentration agreed, which shows that within experimental uncertainty, the sub-µm aerosol was composed of the quantified components. The three estimates of the super-µm aerosol mass concentration did not agree, which indicates that random uncertainties and/or possible systematic errors in aerosol sampling, sizing or analyses were not adequately accounted for. Aerosol chemical composition in air masses from different origins showed differences, which were significant in regard to experimental uncertainties. During the Saharan dust advection period, coarse dust and fine anthropogenic particles were externally mixed. No anthropogenic sulfate could be found in the super-µm dust particles. In contrast, nitrate was shifted towards the aerosol super-µm fraction in presence of desert dust.

scholarly journals Size-segregated aerosol mass closure and chemical composition in Monte Cimone (I) during MINATROC

2003 ◽  
Vol 3 (4) ◽  
pp. 4097-4127 ◽  
Author(s):  
J.-P. Putaud ◽  
R. Van Dingenen ◽  
A. Dell’Acqua ◽  
F. Raes ◽  
E. Matta ◽  
...  
Keyword(s):  
Particle Size ◽  
Chemical Composition ◽  
Mass Concentration ◽  
Saharan Dust ◽  
Dust Particles ◽  
Chemical Analyses ◽  
Aerosol Mass ◽  
Aerosol Mass Concentration ◽  
Random Uncertainties ◽  
Mass Concentrations

Abstract. Physical and chemical characterizations of the atmospheric aerosol was carried out at Mt. Cimone (Italy) during the 4 June–4 July 2000 period. Particle size distributions in the size range 6 nm–10 μm were measured with a differential mobility analyzer (DMA) and a optical particle counter (OPC). Size-segregated aerosol was sampled using a 6-stage low pressure impactor. Aerosol samples were submitted to gravimetric and chemical analyses. Ionic, carbonaceous and refractory components of the aerosol were quantified. We compared the sub- and super-μm aerosol mass concentrations determined by gravimetric measurements (mGM), chemical analyses (mCA), and by converting particle size distribution to aerosol mass concentrations (mSC). Mean random uncertainties associated with the determination of mGM, mCA, and mSD were assessed. The three estimates of the sub-μm aerosol mass concentration agreed, which shows that within experimental uncertainty, the sub-μm aerosol was composed of the quantified components. The three estimates of the super-mm aerosol mass concentration did not agree, which indicates that random uncertainties and/or possible systematic errors in aerosol sampling, sizing or analyses were not adequately accounted for. Aerosol chemical composition in air masses from different origins showed differences, which were significant in regard to experimental uncertainties. During the Saharan dust advection period, coarse dust and fine anthropogenic particles were externally mixed. No anthropogenic sulfate could be found in the super-μm dust particles. In contrast, nitrate was shifted towards the aerosol super-μm fraction in presence of desert dust.

scholarly journals Chemical composition and mixing-state of ice residuals sampled within mixed phase clouds

2011 ◽  
Vol 11 (6) ◽  
pp. 2805-2816 ◽  
Author(s):  
M. Ebert ◽  
A. Worringen ◽  
N. Benker ◽  
S. Mertes ◽  
E. Weingartner ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Carbonaceous Material ◽  
Mixed Phase ◽  
Research Station ◽  
Mixing State ◽  
Anthropogenic Component ◽  
Significant Enrichment ◽  
Alpine Research ◽  
Main Component ◽  
Mixed Phase Clouds

Abstract. During an intensive campaign at the high alpine research station Jungfraujoch, Switzerland, in February/March 2006 ice particle residuals within mixed-phase clouds were sampled using the Ice-counterflow virtual impactor (Ice-CVI). Size, morphology, chemical composition, mineralogy and mixing state of the ice residual and the interstitial (i.e., non-activated) aerosol particles were analyzed by scanning and transmission electron microscopy. Ice nuclei (IN) were identified from the significant enrichment of particle groups in the ice residual (IR) samples relative to the interstitial aerosol. In terms of number lead-bearing particles are enriched by a factor of approximately 25, complex internal mixtures with silicates or metal oxides as major components by a factor of 11, and mixtures of secondary aerosol and carbonaceous material (C-O-S particles) by a factor of 2. Other particle groups (sulfates, sea salt, Ca-rich particles, external silicates) observed in the ice-residual samples cannot be assigned unambiguously as IN. Between 9 and 24% of all IR are Pb-bearing particles. Pb was found as major component in around 10% of these particles (PbO, PbCl2). In the other particles, Pb was found as some 100 nm sized agglomerates consisting of 3–8 nm sized primary particles (PbS, elemental Pb). C-O-S particles are present in the IR at an abundance of 17–27%. The soot component within these particles is strongly aged. Complex internal mixtures occur in the IR at an abundance of 9–15%. Most IN identified at the Jungfraujoch station are internal mixtures containing anthropogenic components (either as main or minor constituent), and it is concluded that admixture of the anthropogenic component is responsible for the increased IN efficiency within mixed phase clouds. The mixing state appears to be a key parameter for the ice nucleation behaviour that cannot be predicted from the sole knowledge of the main component of an individual particle.

scholarly journals Large Contribution of Coarse Mode to Aerosol Microphysical and Optical Properties: Evidence from Ground-Based Observations of a Transpacific Dust Outbreak at a High-Elevation North American Site

2017 ◽  
Vol 74 (5) ◽  
pp. 1431-1443 ◽  
Author(s):  
E. Kassianov ◽  
M. Pekour ◽  
C. Flynn ◽  
L. K. Berg ◽  
J. Beranek ◽  
...  
Keyword(s):  
North American ◽  
High Elevation ◽  
Saharan Dust ◽  
Large Contribution ◽  
Near Surface ◽  
Dust Transport ◽  
Aerosol Mass ◽  
Coarse Mode ◽  
Median Diameter ◽  
Transpacific Transport

Abstract This work is motivated by previous studies of transatlantic transport of Saharan dust and the observed quasi-static nature of coarse mode aerosol with a volume median diameter (VMD) of approximately 3.5 μm. The authors examine coarse mode contributions from transpacific transport of dust to North American aerosol properties using a dataset collected at the high-elevation Storm Peak Laboratory (SPL) and the nearby Atmospheric Radiation Measurement (ARM) Mobile Facility. Collected ground-based data are complemented by quasi-global model simulations and satellite and ground-based observations. The authors identify a major dust event associated mostly with a transpacific plume (about 65% of near-surface aerosol mass) in which the coarse mode with moderate (~3 μm) VMD is distinct and contributes substantially to total aerosol volume (up to 70%) and scattering (up to 40%). The results demonstrate that the identified plume at the SPL site has a considerable fraction of supermicron particles (VMD ~3 μm) and, thus, suggest that these particles have a fairly invariant behavior despite transpacific transport. If confirmed in additional studies, this invariant behavior may simplify considerably parameterizations for size-dependent processes associated with dust transport and removal.

scholarly journals Significant contrasts in aerosol acidity between China and the United States

2021 ◽  
Vol 21 (10) ◽  
pp. 8341-8356
Author(s):  
Bingqing Zhang ◽  
Huizhong Shen ◽  
Pengfei Liu ◽  
Hongyu Guo ◽  
Yongtao Hu ◽  
...  
Keyword(s):  
United States ◽  
Chemical Composition ◽  
The United States ◽  
Formation Mechanisms ◽  
Aerosol Composition ◽  
Ph Values ◽  
Aerosol Acidity ◽  
Aerosol Mass ◽  
The Usa ◽  
Mass Concentrations

Abstract. Aerosol acidity governs several key processes in aerosol physics and chemistry, thus affecting aerosol mass and composition and ultimately climate and human health. Previous studies have reported aerosol pH values separately in China and the United States (USA), implying different aerosol acidity between these two countries. However, there is debate about whether mass concentration or chemical composition is the more important driver of differences in aerosol acidity. A full picture of the pH difference and the underlying mechanisms responsible is hindered by the scarcity of simultaneous measurements of particle composition and gaseous species, especially in China. Here we conduct a comprehensive assessment of aerosol acidity in China and the USA using extended ground-level measurements and regional chemical transport model simulations. We show that aerosols in China are significantly less acidic than in the USA, with pH values 1–2 units higher. Based on a proposed multivariable Taylor series method and a series of sensitivity tests, we identify major factors leading to the pH difference. Compared to the USA, China has much higher aerosol mass concentrations (gas + particle, by a factor of 8.4 on average) and a higher fraction of total ammonia (gas + particle) in the aerosol composition. Our assessment shows that the differences in mass concentrations and chemical composition play equally important roles in driving the aerosol pH difference between China and the USA – increasing the aerosol mass concentrations (by a factor of 8.4) but keeping the relative component contributions the same in the USA as the level in China increases the aerosol pH by ∼ 1.0 units and further shifting the chemical composition from US conditions to China's that are richer in ammonia increases the aerosol pH by ∼ 0.9 units. Therefore, China being both more polluted than the USA and richer in ammonia explains the aerosol pH difference. The difference in aerosol acidity highlighted in the present study implies potential differences in formation mechanisms, physicochemical properties, and toxicity of aerosol particles in these two countries.

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