Experimental and theoretical study on the capture/desorption of gaseous methyl iodide on sea salt aerosols

Iodine-131, when released into the environment during severe nuclear power plant accident can have a high radiological impact on the population at short term [1]. Interaction between gaseous Iodine compounds and aerosols was not considered by the current post-accident management. In this context, this work was focused on investigating the influence of sea salt aerosols on the transport of gaseous methyl iodide (CH3I). The identification of uptake processes as well as the formation of new products at the particle surfaces was the main objectives.We have studied the interaction between NaCl particles as surrogate of sea salt particles and CH3I in various humidity conditions to reproduce the atmospheric conditions.The nature of this interaction was investigated by Infrared Spectroscopy (DRIFTS, Diffuse Reflectance Infrared Fourier Spectroscopy). Solid NaCl was exposed to CH3I (1000 and 500 ppm) with a relative humidity (RH) ranging between 0 and 80%.DRIFTS results clearly evidenced adsorbed CH3I on NaCl particles surface under both dry and humid conditions. The adsorption process can be fitted with First-order Langmuir adsorption isotherm model and exhibited very low uptake coefficients in all the experimental conditions.Additionally, to the CH3I absorption bands, the DRIFT spectrum evidenced typical absorption bands that could be assigned either to the CH2 deformation of CH2I2 or to CH3 degenerate rocking of CH3Cl. The formation of new bands appears only when CH3I is in presence of halogenated salts. However, at RH = 80%, the water layer at the particle surface inhibits the interaction between gaseous CH3I and NaCl surface due to the low solubility of CH3I in water.Theoretical calculations are carried out to complement the experimental results. Isolated hydrated clusters of CH3I are characterized by means of electronic structure calculations and ab initio molecular dynamics is used to mimic the CH3I / salt system at various humidities.Although the uptake and accommodation coefficients of CH3I are quite low, a coverage of particle surface with CH3I-derived compounds may affect the reactivity of the particles and in term the cycling life of Iodine in the atmosphere.Reference[1] Lebel, L. S.; Dickson, R. S.; Glowa, G. A. J. Environ. Radioact. 2016, 151, 82&#8211;93.We acknowledge support by the French government through the Program &#8220;Investissement d'avenir&#8221; through the Labex CaPPA (contract ANR-11-LABX-0005-01) and I-SITE ULNE project OVERSEE (contract ANR-16-IDEX-0004), CPER CLIMIBIO (European Regional Development Fund, Hauts de France council, French Ministry of Higher Education and Research) and French national supercomputing facilities (grants DARI x2016081859 and A0050801859).

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Aerosol distribution around Svalbard during intense easterly winds

Atmospheric Chemistry and Physics ◽

10.5194/acp-10-1473-2010 ◽

2010 ◽

Vol 10 (4) ◽

pp. 1473-1490 ◽

Cited By ~ 22

Author(s):

A. Dörnbrack ◽

I. S. Stachlewska ◽

C. Ritter ◽

R. Neuber

Keyword(s):

Sea Salt ◽

Airborne Lidar ◽

The Arctic ◽

Aerosol Layer ◽

Atmospheric Conditions ◽

Sea Salt Aerosols ◽

Aerosol Distribution ◽

Weather Situation ◽

Low Level Jet ◽

Aerosol Plume

Abstract. This paper reports on backscatter and depolarization measurements by an airborne lidar in the Arctic during the ASTAR 2004 campaign. A unique weather situation facilitated the observation of the aerosol concentration under strongly forced atmospheric conditions. The vigorous easterly winds distorted the flow past Svalbard in such a way that mesoscale features were visible in the remote-sensing observations: The formation of a well-mixed aerosol layer inside the Adventdalen and the subsequent thinning of the aerosol plume were observed over the Isfjorden. Additionally, mobilization of sea salt aerosols due to a coastal low-level jet at the northern tip of Svalbard resulted in a sloped boundary layer toward north. Mesoscale numerical modelling was applied to identify the sources of the aerosol particles and to explain the observed patterns.

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Relative Intensities in ED Patterns From Thin Gold Films

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100096436 ◽

1972 ◽

Vol 30 ◽

pp. 636-637

Author(s):

R. H. Morriss ◽

J. D. C. Peng ◽

C. D. Melvin

Keyword(s):

Theoretical Calculations ◽

Diffraction Theory ◽

Gold Films ◽

Reasonable Accuracy ◽

Experimental Conditions ◽

Crystal Perfection ◽

Heavy Atoms ◽

Fine Focus ◽

Convergent Beam ◽

Beam Diffraction

Although dynamical diffraction theory was modified for electrons by Bethe in 1928, relatively few calculations have been carried out because of computational difficulties. Even fewer attempts have been made to correlate experimental data with theoretical calculations. The experimental conditions are indeed stringent - not only is a knowledge of crystal perfection, morphology, and orientation necessary, but other factors such as specimen contamination are important and must be carefully controlled. The experimental method of fine-focus convergent-beam electron diffraction has been successfully applied by Goodman and Lehmpfuhl to single crystals of MgO containing light atoms and more recently by Lynch to single crystalline (111) gold films which contain heavy atoms. In both experiments intensity distributions were calculated using the multislice method of n-beam diffraction theory. In order to obtain reasonable accuracy Lynch found it necessary to include 139 beams in the calculations for gold with all but 43 corresponding to beams out of the [111] zone.

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Impact of the particle mixing state on the hygroscopicity of internally mixed sodium chloride-ammonium sulfate single droplets: A theoretical and experimental study

Physical Chemistry Chemical Physics ◽

10.1039/d1cp01574e ◽

2021 ◽

Author(s):

Yeny A. Tobon ◽

Danielle El Hajj ◽

Samantha Seng ◽

Ferdaous Bengrad ◽

Myriam Moreau ◽

...

Keyword(s):

Experimental Study ◽

Sodium Chloride ◽

Ammonium Sulfate ◽

Atmospheric Transport ◽

Sea Salt ◽

Main Constituent ◽

Sea Salt Aerosols ◽

Particle Mixing ◽

Secondary Aerosols ◽

Single Droplets

Sodium chloride (NaCl) is the main constituent of sea-salt aerosols. During atmospheric transport, sea-salt aerosols can interact with gases and other particles including secondary aerosols containing ammonium sulfate ((NH4)2SO4). This...

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Trace elements and sea salt aerosols over the sea areas around the Indian sub-continent

Deep Sea Research Part B Oceanographic Literature Review ◽

10.1016/0198-0254(85)92747-5 ◽

1985 ◽

Vol 32 (9) ◽

pp. 739

Keyword(s):

Trace Elements ◽

Sea Salt ◽

Sea Salt Aerosols

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The Inhomogeneity Effect of Sea Salt Aerosols on the TOA Polarized Radiance at the Scattering Angles Ranging From 170° to 175°

IEEE Transactions on Geoscience and Remote Sensing ◽

10.1109/tgrs.2021.3099026 ◽

2021 ◽

pp. 1-12

Author(s):

Meng Li ◽

Lei Bi ◽

Wushao Lin ◽

Fuzhong Weng ◽

Shuangyan He ◽

...

Keyword(s):

Sea Salt ◽

Sea Salt Aerosols

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Temperature uniformity in the CERN CLOUD chamber

Atmospheric Measurement Techniques ◽

10.5194/amt-10-5075-2017 ◽

2017 ◽

Vol 10 (12) ◽

pp. 5075-5088 ◽

Cited By ~ 5

Author(s):

António Dias ◽

Sebastian Ehrhart ◽

Alexander Vogel ◽

Christina Williamson ◽

João Almeida ◽

...

Keyword(s):

Steady State ◽

Air Temperature ◽

Elevated Temperatures ◽

Trace Gases ◽

Vertical Direction ◽

Cloud Chamber ◽

Temperature Uniformity ◽

Atmospheric Conditions ◽

Cloud Droplets ◽

Experimental Conditions

Abstract. The CLOUD (Cosmics Leaving OUtdoor Droplets) experiment at CERN (European Council for Nuclear Research) investigates the nucleation and growth of aerosol particles under atmospheric conditions and their activation into cloud droplets. A key feature of the CLOUD experiment is precise control of the experimental parameters. Temperature uniformity and stability in the chamber are important since many of the processes under study are sensitive to temperature and also to contaminants that can be released from the stainless steel walls by upward temperature fluctuations. The air enclosed within the 26 m3 CLOUD chamber is equipped with several arrays (strings) of high precision, fast-response thermometers to measure its temperature. Here we present a study of the air temperature uniformity inside the CLOUD chamber under various experimental conditions. Measurements were performed under calibration conditions and run conditions, which are distinguished by the flow rate of fresh air and trace gases entering the chamber at 20 and up to 210 L min−1, respectively. During steady-state calibration runs between −70 and +20 °C, the air temperature uniformity is better than ±0.06 °C in the radial direction and ±0.1 °C in the vertical direction. Larger non-uniformities are present during experimental runs, depending on the temperature control of the make-up air and trace gases (since some trace gases require elevated temperatures until injection into the chamber). The temperature stability is ±0.04 °C over periods of several hours during either calibration or steady-state run conditions. During rapid adiabatic expansions to activate cloud droplets and ice particles, the chamber walls are up to 10 °C warmer than the enclosed air. This results in temperature differences of ±1.5 °C in the vertical direction and ±1 °C in the horizontal direction, while the air returns to its equilibrium temperature with a time constant of about 200 s.

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Laboratory study on new particle formation from the reaction OH + SO2: influence of experimental conditions, H2O vapour, NH3 and the amine tert-butylamine on the overall process

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-10-6447-2010 ◽

2010 ◽

Vol 10 (3) ◽

pp. 6447-6484 ◽

Cited By ~ 4

Author(s):

T. Berndt ◽

F. Stratmann ◽

M. Sipilä ◽

J. Vanhanen ◽

T. Petäjä ◽

...

Keyword(s):

Relative Humidity ◽

High Sensitivity ◽

Particle Growth ◽

Counting Efficiency ◽

Oh Radicals ◽

Atmospheric Conditions ◽

Promoting Effect ◽

Experimental Conditions ◽

H2so4 Concentration ◽

Tert Butylamine

Abstract. Nucleation experiments starting from the reaction of OH radicals with SO2 have been performed in the IfT-LFT flow tube under atmospheric conditions at 293±0.5 K for a relative humidity of 13–61%. The presence of different additives (H2, CO, 1,3,5-trimethylbenzene) for adjusting the OH radical concentration and resulting OH levels in the range (4–300)·105 molecule cm−3 did not influence the nucleation process itself. The number of detected particles as well as the threshold H2SO4 concentration needed for nucleation was found to be strongly dependent on the counting efficiency of the used counting devices. High-sensitivity particle counters allowed the measurement of freshly nucleated particles with diameters down to about 1.5 nm. A parameterization of the experimental data was developed using power law equations for H2SO4 and H2O vapour. The exponent for H2SO4 from different measurement series was in the range of 1.7–2.1 being in good agreement with those arising from analysis of nucleation events in the atmosphere. For increasing relative humidity, an increase of the particle number was observed. The exponent for H2O vapour was found to be 3.1 representing a first estimate. Addition of 1.2·1011 molecule cm−3 or 1.2·1012 molecule cm−3 of NH3 (range of atmospheric NH3 peak concentrations) revealed that NH3 has a measureable, promoting effect on the nucleation rate under these conditions. The promoting effect was found to be more pronounced for relatively dry conditions. NH3 showed a contribution to particle growth. Adding the amine tert-butylamine instead of NH3, the enhancing impact for nucleation and particle growth appears to be stronger.

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Laser filament-induced aerosol formation

Atmospheric Chemistry and Physics ◽

10.5194/acp-13-4593-2013 ◽

2013 ◽

Vol 13 (9) ◽

pp. 4593-4604 ◽

Cited By ~ 20

Author(s):

H. Saathoff ◽

S. Henin ◽

K. Stelmaszczyk ◽

M. Petrarca ◽

R. Delagrange ◽

...

Keyword(s):

Particle Production ◽

Ambient Air ◽

Particle Formation ◽

Oxygen Mixture ◽

Atmospheric Conditions ◽

Aerosol Formation ◽

Experimental Conditions ◽

Particle Yield ◽

The Given ◽

Terawatt Laser

Abstract. Using the aerosol and cloud simulation chamber AIDA, we investigated the laser filament induced particle formation in ambient air, humid synthetic air, humid nitrogen, argon–oxygen mixture, and pure argon in order to simulate the particle formation under realistic atmospheric conditions as well as to investigate the influence of typical gas-phase atmospheric constituents on the particle formation. Terawatt laser plasma filaments generated new particles in the size range 3 to 130 nm with particle production rates ranging from 1 × 107 to 5 × 109 cm−3 plasma s−1 for the given experimental conditions. In all cases the particle formation rates increased exponentially with the water content of the gas mixture. Furthermore, the presence of a few ppb of trace gases like SO2 and α-pinene clearly enhanced the particle yield by number, the latter also by mass. Our findings suggest that new particle formation is efficiently supported by oxidized species like acids generated by the photoionization of both major and minor components of the air, including N2, NH3, SO2 and organics.

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