scholarly journals Rapid growth of organic aerosol nanoparticles over a wide tropospheric temperature range

2018 ◽  
Vol 115 (37) ◽  
pp. 9122-9127 ◽  
Author(s):  
Dominik Stolzenburg ◽  
Lukas Fischer ◽  
Alexander L. Vogel ◽  
Martin Heinritzi ◽  
Meredith Schervish ◽  
...  
Keyword(s):  
Growth Rates ◽  
Rapid Growth ◽  
Aerosol Particles ◽  
Particle Growth ◽  
Molecular Cluster ◽  
Tropospheric Temperature ◽  
Initial Growth ◽  
European Organization ◽  
Cold Temperatures ◽  
Wide Range

Nucleation and growth of aerosol particles from atmospheric vapors constitutes a major source of global cloud condensation nuclei (CCN). The fraction of newly formed particles that reaches CCN sizes is highly sensitive to particle growth rates, especially for particle sizes <10 nm, where coagulation losses to larger aerosol particles are greatest. Recent results show that some oxidation products from biogenic volatile organic compounds are major contributors to particle formation and initial growth. However, whether oxidized organics contribute to particle growth over the broad span of tropospheric temperatures remains an open question, and quantitative mass balance for organic growth has yet to be demonstrated at any temperature. Here, in experiments performed under atmospheric conditions in the Cosmics Leaving Outdoor Droplets (CLOUD) chamber at the European Organization for Nuclear Research (CERN), we show that rapid growth of organic particles occurs over the range from −25 °C to 25 °C. The lower extent of autoxidation at reduced temperatures is compensated by the decreased volatility of all oxidized molecules. This is confirmed by particle-phase composition measurements, showing enhanced uptake of relatively less oxygenated products at cold temperatures. We can reproduce the measured growth rates using an aerosol growth model based entirely on the experimentally measured gas-phase spectra of oxidized organic molecules obtained from two complementary mass spectrometers. We show that the growth rates are sensitive to particle curvature, explaining widespread atmospheric observations that particle growth rates increase in the single-digit-nanometer size range. Our results demonstrate that organic vapors can contribute to particle growth over a wide range of tropospheric temperatures from molecular cluster sizes onward.

scholarly journals The contribution of sulphuric acid to atmospheric particle formation and growth: a comparison between boundary layers in Northern and Central Europe

2005 ◽  
Vol 5 (7) ◽  
pp. 1773-1785 ◽  
Author(s):  
V. Fiedler ◽  
M. Dal Maso ◽  
M. Boy ◽  
H. Aufmhoff ◽  
J. Hoffmann ◽  
...  
Keyword(s):  
Sulphuric Acid ◽  
Central Europe ◽  
Growth Rates ◽  
Particle Number ◽  
Particle Growth ◽  
Particle Formation ◽  
Initial Growth ◽  
Size Distributions ◽  
Vapor Source ◽  
Particle Formation And Growth

Abstract. Atmospheric gaseous sulphuric acid was measured and its influence on particle formation and growth was investigated building on aerosol data. The measurements were part of the EU-project QUEST and took place at two different measurement sites in Northern and Central Europe (Hyytiälä, Finland, March-April 2003 and Heidelberg, Germany, March-April 2004). From a comprehensive data set including sulphuric acid, particle number size distributions and meteorological data, particle growth rates, particle formation rates and source rates of condensable vapors were inferred. Growth rates were determined in two different ways, from particle size distributions as well as from a so-called timeshift analysis. Moreover, correlations between sulphuric acid and particle number concentration between 3 and 6 nm were examined and the influence of air masses of different origin was investigated. Measured maximum concentrations of sulphuric acid were in the range from 1x106 to 16x106cm-3. The gaseous sulphuric acid lifetime with respect to condensation on aerosol particles ranged from 2 to 33min in Hyytiälä and from 0.5 to 8 min in Heidelberg. Most calculated values (growth rates, formation rates, vapor source rates) were considerably higher in Central Europe (Heidelberg), due to the more polluted air and higher preexistent aerosol concentrations. Close correlations between H2SO4 and nucleation mode particles (size range: 3-6 nm) were found on most days at both sites. The percentage contribution of sulphuric acid to particle growth was below 10% at both places and to initial growth below 20%. An air mass analysis indicated that at Heidelberg new particles were formed predominantly in air advected from southwesterly directions.

scholarly journals Enhanced growth rate of atmospheric particles from sulfuric acid

2020 ◽  
Vol 20 (12) ◽  
pp. 7359-7372 ◽  
Author(s):  
Dominik Stolzenburg ◽  
Mario Simon ◽  
Ananth Ranjithkumar ◽  
Andreas Kürten ◽  
Katrianne Lehtipalo ◽  
...  
Keyword(s):  
Growth Rate ◽  
Sulfuric Acid ◽  
Growth Rates ◽  
Particle Number ◽  
Nuclear Research ◽  
Initial Growth ◽  
Atmospheric Conditions ◽  
European Organization ◽  
Dipole Interactions ◽  
The Impact

Abstract. In the present-day atmosphere, sulfuric acid is the most important vapour for aerosol particle formation and initial growth. However, the growth rates of nanoparticles (<10 nm) from sulfuric acid remain poorly measured. Therefore, the effect of stabilizing bases, the contribution of ions and the impact of attractive forces on molecular collisions are under debate. Here, we present precise growth rate measurements of uncharged sulfuric acid particles from 1.8 to 10 nm, performed under atmospheric conditions in the CERN (European Organization for Nuclear Research) CLOUD chamber. Our results show that the evaporation of sulfuric acid particles above 2 nm is negligible, and growth proceeds kinetically even at low ammonia concentrations. The experimental growth rates exceed the hard-sphere kinetic limit for the condensation of sulfuric acid. We demonstrate that this results from van der Waals forces between the vapour molecules and particles and disentangle it from charge–dipole interactions. The magnitude of the enhancement depends on the assumed particle hydration and collision kinetics but is increasingly important at smaller sizes, resulting in a steep rise in the observed growth rates with decreasing size. Including the experimental results in a global model, we find that the enhanced growth rate of sulfuric acid particles increases the predicted particle number concentrations in the upper free troposphere by more than 50 %.

scholarly journals The contribution of sulphuric acid to atmospheric particle formation and growth: a comparison between boundary layers in Northern and Central Europe

2005 ◽  
Vol 5 (1) ◽  
pp. 573-605 ◽  
Author(s):  
V. Fiedler ◽  
M. Dal Maso ◽  
M. Boy ◽  
H. Aufmhoff ◽  
J. Hoffmann ◽  
...  
Keyword(s):  
Sulphuric Acid ◽  
Central Europe ◽  
Growth Rates ◽  
Particle Number ◽  
Particle Growth ◽  
Particle Formation ◽  
Initial Growth ◽  
Size Distributions ◽  
Vapor Source ◽  
Particle Formation And Growth

Abstract. Atmospheric gaseous sulphuric acid was measured and its influence on particle formation and growth was investigated building on aerosol data. The measurements were part of the EU-project QUEST and took place at two different measurement sites in Northern and Central Europe (Hyytiälä, Finland, March–April 2003 and Heidelberg, Germany, March–April 2004). From a comprehensive data set including particle number size distributions, sulphuric acid, and meteorological data, particle growth rates, particle formation rates and source rates of condensable vapors were calculated. Growth rates were determined in two different ways, from particle size distributions as well as from a so-called timeshift analysis. Moreover, correlations between sulphuric acid and particle number concentration between 3 and 6 nm were examined and the influence of different air masses was analyzed. Measured concentrations of sulphuric acid were in the range from 2·106 to 16·106 cm-3. The gaseous sulphuric acid lifetime with respect to condensation on aerosol particles ranged from 2 to 33 min in Hyytiälä and from 28 s to 8 min in Heidelberg. Most calculated values (growth rates, formation rates, vapor source rates) were considerably higher in Central Europe (Heidelberg), due to the more polluted air and higher preexistent aerosol concentrations. Close correlations between H2SO4 and nucleation mode particles (size range: 3–6 nm) were found on many days at both sites but several observation days also lacked such correlations. The percentage contribution of sulphuric acid to particle growth was below 10% at both places, to initial growth below 20%. An air mass analysis indicated that at Heidelberg new particles were formed predominantly in air advected from southwesterly directions.

Selecting a PRO-CTCAE based subset for patient reported symptom monitoring during lung cancer treatment (Preprint)

2020 ◽  
Author(s):  
Evalien Veldhuijzen ◽  
Iris Walraven ◽  
Jose Belderbos
Keyword(s):  
Lung Cancer ◽  
Clinical Practice ◽  
Cancer Patients ◽  
Treatment Modalities ◽  
European Organization ◽  
Specific Patient ◽  
Symptom Monitoring ◽  
Lung Cancer Patients ◽  
Wide Range ◽  
Patient Reported

BACKGROUND The Patient Reported Outcomes Version of the Common Terminology Criteria of Adverse Events (PRO-CTCAE) item library covers a wide range of symptoms relevant for oncology care. To enable implementation of PRO-CTCAE-based symptom monitoring in clinical practice, there is a need to select a subset of items relevant for specific patient populations. OBJECTIVE The aim of this study was to develop a PRO-CTCAE subset relevant for patients with lung cancer. METHODS The PRO-CTCAE-based subset for lung cancer patients was generated using a mixed methods approach based on the European Organization for Research and Treatment of Cancer (EORTC) guidelines for developing questionnaires, consisting of a literature review and semi-structured interviews with both lung cancer patients and health care practitioners (HCPs). Both patients and HCPs were queried on the relevance and impact of all PRO-CTCAE items. Results were summarized and, after a final round of expert review, a selection of clinically relevant items for lung cancer patients was made. RESULTS A heterogeneous group of lung cancer patients (n=25) from different treatment modalities and HCPs (n=22) participated in the study. A final list of eight relevant PRO-CTCAE items was created: decreased appetite, cough, shortness of breath, fatigue, constipation, nausea, sadness, and pain (general). CONCLUSIONS Based on literature and both professional and patient input, a subset of PRO-CTCAE items has been identified for use in lung cancer patients in clinical practice. Future work is needed to confirm the validity and effectiveness of this PRO-CTCAE lung cancer subset internationally, and in the real-world clinical practice setting.

scholarly journals Airborne measurements of trace gas and aerosol particle emissions from biomass burning in Amazonia

2005 ◽  
Vol 5 (11) ◽  
pp. 2989-3002 ◽  
Author(s):  
P. Guyon ◽  
G. P. Frank ◽  
M. Welling ◽  
D. Chand ◽  
P. Artaxo ◽  
...  
Keyword(s):  
Large Scale ◽  
Particle Number ◽  
Aerosol Particles ◽  
Secondary Growth ◽  
Combustion Efficiency ◽  
Vertical Transport ◽  
Airborne Measurements ◽  
Sampling Campaign ◽  
Wide Range ◽  
Emission Ratios

Abstract. As part of the LBA-SMOCC (Large-Scale Biosphere-Atmosphere Experiment in Amazonia - Smoke, Aerosols, Clouds, Rainfall, and Climate) 2002 campaign, we studied the emission of carbon monoxide (CO), carbon dioxide (CO2), and aerosol particles from Amazonian deforestation fires using an instrumented aircraft. Emission ratios for aerosol number (CN) relative to CO (ERCN/CO) fell in the range 14-32 cm-3 ppb-1 in most of the investigated smoke plumes. Particle number emission ratios have to our knowledge not been previously measured in tropical deforestation fires, but our results are in agreement with values usually found from tropical savanna fires. The number of particles emitted per amount biomass burned was found to be dependent on the fire conditions (combustion efficiency). Variability in ERCN/CO between fires was similar to the variability caused by variations in combustion behavior within each individual fire. This was confirmed by observations of CO-to-CO2 emission ratios (ERCO/CO2), which stretched across the same wide range of values for individual fires as for all the fires observed during the sampling campaign, reflecting the fact that flaming and smoldering phases are present simultaneously in deforestation fires. Emission factors (EF) for CO and aerosol particles were computed and a correction was applied for the residual smoldering combustion (RSC) fraction of emissions that are not sampled by the aircraft, which increased the EF by a factor of 1.5-2.1. Vertical transport of smoke from the boundary layer (BL) to the cloud detrainment layer (CDL) and the free troposphere (FT) was found to be a very common phenomenon. We observed a 20% loss in particle number as a result of this vertical transport and subsequent cloud processing, attributable to in-cloud coagulation. This small loss fraction suggests that this mode of transport is very efficient in terms of particle numbers and occurs mostly via non-precipitating clouds. The detrained aerosol particles released in the CDL and FT were larger than in the unprocessed smoke, mostly due to coagulation and secondary growth, and therefore more efficient at scattering radiation and nucleating cloud droplets. This process may have significant atmospheric implications on a regional and larger scale.

Abstract 180: The Growth Rate of Early DWI Lesions is Highly Variable and Associated with Penumbral Salvage and Clinical Outcomes Following Endovascular Reperfusion

Stroke ◽  
2013 ◽  
Vol 44 (suppl_1) ◽  
Author(s):  
Hayley M Wheeler ◽  
Michael Mlynash ◽  
Manabu Inoue ◽  
Aaryani Tipirneni ◽  
John Liggins ◽  
...  
Keyword(s):  
Growth Rate ◽  
Acute Stroke ◽  
Clinical Outcomes ◽  
Endovascular Therapy ◽  
Symptom Onset ◽  
Growth Rates ◽  
Initial Growth ◽  
Stroke Patients ◽  
Final Volume ◽  
Favorable Clinical Response

Background: The degree of variability in the rate of early DWI expansion has not been well characterized. We hypothesized that Target Mismatch patients with slowly expanding DWI lesions have more penumbral salvage and better clinical outcomes following endovascular reperfusion than Target Mismatch patients with rapidly expanding DWI lesions. Methods: This substudy of DEFUSE 2 included all patients with a clearly established time of symptom onset. The initial DWI growth rate was determined from the baseline scan by assuming a volume 0 ml just prior to symptom onset. Target Mismatch patients who achieved reperfusion (>50% reduction in PWI after endovascular therapy), were categorized into tertiles according to their initial DWI growth rates. For each tertile, penumbral salvage (comparison of final volume to the volume of PWI (Tmax > 6 sec)/ DWI mismatch prior to endovascular therapy), favorable clinical response, and good functional outcome (see figure for definitions) were calculated. We also compared the growth rate in patients with the Target mismatch vs. Malignant Profile. Results: 64 patients were eligible for this study. Target mismatch patients (n=44) had initial growth rates (range 0 to 43 ml/hr, median of 3 ml/hr) that were significantly less than the growth rates in Malignant profile (n=7) patients (12 to 92 ml/hr, median 39 ml/hr; p < 0.001). In Target mismatch patients who achieved reperfusion (n=30), slower early DWI growth rates were associated with better clinical outcomes (p<0.05) and a trend toward more penumbral salvage (n=27, p=0.137). Conclusions: The growth rate of early DWI lesions in acute stroke patients is highly variable; Malignant profile patients have higher growth rates than other MRI profiles. Among Target Mismatch patients, a slower rate of DWI growth is associated with a greater degree of penumbral salvage and improved clinical outcomes following endovascular reperfusion.

Evaporite Palynology: a case study on the Permian (Lopgingian) Zechstein Sea

2021 ◽  
pp. jgs2020-174
Author(s):  
Martha E. Gibson ◽  
David J. Bodman
Keyword(s):  
Thermal Conductivity ◽  
Heat Flux ◽  
Rapid Growth ◽  
Western Europe ◽  
Thermal Maturity ◽  
Near Surface ◽  
Wide Range ◽  
Terrestrial Environments ◽  
Insight Into

Evaporites characterize the Lopingian of Europe but present obstacles for biostratigraphic analysis. Here we present a case study for processing the Lopingian Zechstein Group evaporites of central-western Europe for the recovery of palynomorph assemblages. We demonstrate that full recovery is easily achieved with two main modes of palynomorph preservation observed; palynomorphs are either exceptionally well-preserved and orange-brown in colour, or poorly-preserved, brown-black, opaque and fragmented. The latter are reminiscent of palynomorphs of high thermal maturity. However, we propose that the intact nature of preservation is a result of the rapid growth of near-surface halite crystals, with their darkening a consequence of locally-enhanced heat flux due to the relatively high thermal conductivity of salt. This case study has enabled novel insight into an otherwise undescribed environment, and demonstrates the utility and possibility of extracting palynomorphs from a variety of rock salt types. This method should be applicable to a wide range of ancient evaporite and could also be applied to other Permian evaporite systems, which are used as analogues for extra-terrestrial environments.

Subharmonic resonance of short internal standing waves by progressive surface waves

1996 ◽  
Vol 321 ◽  
pp. 217-233 ◽  
Author(s):  
D. F. Hill ◽  
M. A. Foda
Keyword(s):  
Surface Wave ◽  
Internal Wave ◽  
Surface Waves ◽  
Internal Waves ◽  
Growth Rates ◽  
Evolution Equations ◽  
Standing Waves ◽  
Second Order ◽  
Inviscid Limit ◽  
Initial Growth

Experimental evidence and a theoretical formulation describing the interaction between a progressive surface wave and a nearly standing subharmonic internal wave in a two-layer system are presented. Laboratory investigations into the dynamics of an interface between water and a fluidized sediment bed reveal that progressive surface waves can excite short standing waves at this interface. The corresponding theoretical analysis is second order and specifically considers the case where the internal wave, composed of two oppositely travelling harmonics, is much shorter than the surface wave. Furthermore, the analysis is limited to the case where the internal waves are small, so that only the initial growth is described. Approximate solution to the nonlinear boundary value problem is facilitated through a perturbation expansion in surface wave steepness. When certain resonance conditions are imposed, quadratic interactions between any two of the harmonics are in phase with the third, yielding a resonant triad. At the second order, evolution equations are derived for the internal wave amplitudes. Solution of these equations in the inviscid limit reveals that, at this order, the growth rates for the internal waves are purely imaginary. The introduction of viscosity into the analysis has the effect of modifying the evolution equations so that the growth rates are complex. As a result, the amplitudes of the internal waves are found to grow exponentially in time. Physically, the viscosity has the effect of adjusting the phase of the pressure so that there is net work done on the internal waves. The growth rates are, in addition, shown to be functions of the density ratio of the two fluids, the fluid layer depths, and the surface wave conditions.

scholarly journals Aerosol chemistry and particle growth events at an urban downwind site in North China Plain

2018 ◽  
Vol 18 (19) ◽  
pp. 14637-14651 ◽  
Author(s):  
Yingjie Zhang ◽  
Wei Du ◽  
Yuying Wang ◽  
Qingqing Wang ◽  
Haofei Wang ◽  
...  
Keyword(s):  
Growth Rates ◽  
North China Plain ◽  
North China ◽  
Particle Growth ◽  
Early Morning ◽  
Scanning Mobility Particle Sizer ◽  
Average Mass ◽  
The North ◽  
Haze Pollution ◽  
Engine Version

Abstract. The North China Plain (NCP) has experienced frequent severe haze pollution events in recent years. While extensive measurements have been made in megacities, aerosol sources, processes, and particle growth at urban downwind sites remain less understood. Here, an aerosol chemical speciation monitor and a scanning mobility particle sizer, along with a suite of collocated instruments, were deployed at the downwind site of Xingtai, a highly polluted city in the NCP, for real-time measurements of submicron aerosol (PM1) species and particle number size distributions during May and June 2016. The average mass concentration of PM1 was 30.5 (±19.4) µg m−3, which is significantly lower than that during wintertime. Organic aerosols (OAs) constituted the major fraction of PM1 (38 %), followed by sulfate (25 %) and nitrate (14 %). Positive matrix factorization with the multilinear engine version 2 showed that oxygenated OA (OOA) was the dominant species in OA throughout the study, on average accounting for 78 % of OA, while traffic and cooking emissions both accounted for 11 % of OA. Our results highlight that aerosol particles at the urban downwind site were highly aged and mainly from secondary formation. However, the diurnal cycle also illustrated the substantial influence of urban emissions on downwind sites, which are characterized by similar pronounced early morning peaks for most aerosol species. New particle formation and growth events were also frequently observed (58 % of the time) on both clean and polluted days. Particle growth rates varied from 1.2 to 4.9 nm h−1 and our results showed that sulfate and OOA played important roles in particle growth during clean periods, while OOA was more important than sulfate during polluted events. Further analyses showed that particle growth rates have no clear dependence on air mass trajectories.

Single Crystal Wurtzitic Aluminum Nitride Growth on Silicon Using Supersonic Gas Jets

1995 ◽  
Vol 395 ◽  
Author(s):  
S. A. Ustin ◽  
L. Lauhon ◽  
K. A. Brown ◽  
D. Q. Hu ◽  
W. Ho
Keyword(s):  
Aluminum Nitride ◽  
Growth Rates ◽  
High Energy ◽  
X Ray Diffraction ◽  
Rutherford Back Scattering ◽  
X Ray ◽  
Supersonic Molecular Beam ◽  
Supersonic Beams ◽  
Wide Range

ABSTRACTHighly oriented aluminum nitride (0001) films have been grown on Si(001) and Si (111) substrates at temperatures between 550° C and 775° C with dual supersonic molecular beam sources. Triethylaluminum (TEA;[(C2H5)3Al]) and ammonia (NH3) were used as precursors. Hydrogen, helium, and nitrogen were used as seeding gases for the precursors, providing a wide range of possible kinetic energies for the supersonic beams due to the disparate masses of the seed gases. Growth rates of AIN were found to depend strongly on the substrate orientation and the kinetic energy of the incident precursor; a significant increase in growth rate is seen when seeding in hydrogen or helium as opposed to nitrogen. Growth rates were 2–3 times greater on Si(001) than on Si(111). Structural characterization of the films was done by reflection high energy electron diffraction (RHEED) and x-ray diffraction (XRD). X-ray rocking curve (XRC) full-width half-maxima (FWHM) were seen as small as 2.5°. Rutherford back scattering (RBS) was used to determine the thickness of the films and their chemical composition. Films were shown to be nitrogen rich, deviating from perfect stoichiometry by 10%–20%. Surface analysis was performed by Auger electron spectroscopy (AES).

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