scholarly journals Multicomponent diffusion in atmospheric aerosol particles

2021 ◽  
Author(s):  
Brandon J. Wallace ◽  
Chelsea L. Price ◽  
James F. Davies ◽  
Thomas C. Preston
Keyword(s):  
Mass Transport ◽  
Condensed Phase ◽  
Atmospheric Aerosol ◽  
Aerosol Particles ◽  
Multicomponent Diffusion ◽  
Electrodynamic Balance ◽  
Atmospheric Aerosol Particles

Condensed phase mass transport in single aerosol particles is investigated using a linear quadrupole electrodynamic balance (LQ-EDB) and the Maxwell–Stefan (MS) framework.

scholarly journals Halogen activation and radical cycling initiated by imidazole-2-carboxaldehyde photochemistry

2019 ◽  
Vol 19 (16) ◽  
pp. 10817-10828 ◽  
Author(s):  
Pablo Corral Arroyo ◽  
Raffael Aellig ◽  
Peter A. Alpert ◽  
Rainer Volkamer ◽  
Markus Ammann
Keyword(s):  
Excited States ◽  
Condensed Phase ◽  
Atmospheric Aerosol ◽  
Uv Light ◽  
Aerosol Particles ◽  
Radical Reaction ◽  
Sea Spray ◽  
Atmospheric Aerosol Particles ◽  
Halogen Activation ◽  
Triplet Excited States

Abstract. Atmospheric aerosol particles can contain light-absorbing organic compounds, also referred to as brown carbon (BrC). The ocean surface and sea spray aerosol particles can also contain light-absorbing organic species referred to as chromophoric dissolved organic matter (CDOM). Many BrC and CDOM species can contain carbonyls, dicarbonyls or aromatic carbonyls such as imidazole-2-carboxaldehyde (IC), which may act as photosensitizers because they form triplet excited states upon UV–VIS light absorption. These triplet excited states are strong oxidants and may initiate catalytic radical reaction cycles within and at the surface of atmospheric aerosol particles, thereby increasing the production of condensed-phase reactive oxygen species (ROS). Triplet states or ROS can also react with halides, generating halogen radicals and molecular halogen compounds. In particular, molecular halogens can be released into the gas phase, which is one halogen activation pathway. In this work, we studied the influence of bromide and iodide on the photosensitized production and release of hydroperoxy radicals (HO2) upon UV irradiation of films in a coated wall flow tube (CWFT) containing IC in a matrix of citric acid (CA) irradiated with UV light. In addition, we measured the iodine release upon irradiation of IC ∕ CA films in the CWFT. We developed a kinetic model coupling photosensitized CA oxidation with condensed-phase halogen chemistry to support data analysis and assessment of atmospheric implications in terms of HO2 production and halogen release in sea spray particles. As indicated by the experimental results and confirmed by the model, significant recycling of halogen species occurred via scavenging reactions with HO2. These prevented the full and immediate release of the molecular halogen (bromine and iodine) produced. Recycling was stronger at low relative humidity, attributed to diffusion limitations. Our findings also show that the HO2 production from BrC or CDOM photosensitized reactions can increase due to the presence of halides, leading to high HO2 turnover, in spite of low release due to the scavenging reactions. We estimated the iodine production within sea salt aerosol particles due to iodide oxidation by ozone (O3) at 5.0×10-6 M s−1 assuming O3 was in Henry's law equilibrium with the particle. However, using an O3 diffusion coefficient of 1×10-12 cm2 s−1, iodine activation in an aged, organic-rich sea spray is estimated to be 5.5×10-8 M s−1. The estimated iodine production from BrC photochemistry based on the results reported here amounts to 4.1×10-7 M s−1 and indicates that BrC photochemistry can exceed O3 reactive uptake in controlling the rates of iodine activation from sea spray particles under dry or cold conditions where diffusion is slow within particles.

scholarly journals Calibration of LACIS as a CCN detector and its use in measuring activation and hygroscopic growth of atmospheric aerosol particles

2006 ◽  
Vol 6 (12) ◽  
pp. 4519-4527 ◽  
Author(s):  
H. Wex ◽  
A. Kiselev ◽  
M. Ziese ◽  
F. Stratmann
Keyword(s):  
Sodium Chloride ◽  
Wall Temperature ◽  
Atmospheric Aerosol ◽  
Volume Fraction ◽  
Cloud Condensation Nuclei ◽  
Aerosol Particles ◽  
Urban Aerosol ◽  
Hygroscopic Growth ◽  
Atmospheric Aerosol Particles ◽  
Droplet Activation

Abstract. A calibration for LACIS (Leipzig Aerosol Cloud Interaction Simulator) for its use as a CCN (cloud condensation nuclei) detector has been developed. For this purpose, sodium chloride and ammonium sulfate particles of known sizes were generated and their grown sizes were detected at the LACIS outlet. From these signals, the effective critical super-saturation was derived as a function of the LACIS wall temperature. With this, LACIS is calibrated for its use as a CCN detector. The applicability of LACIS for measurements of the droplet activation, and also of the hygroscopic growth of atmospheric aerosol particles was tested. The activation of the urban aerosol particles used in the measurements was found to occur at a critical super-saturation of 0.46% for particles with a dry diameter of 75 nm, and at 0.42% for 85 nm, respectively. Hygroscopic growth was measured for atmospheric aerosol particles with dry diameters of 150, 300 and 350 nm at relative humidities of 98 and 99%, and it was found that the larger dry particles contained a larger soluble volume fraction of about 0.85, compared to about 0.6 for the 150 nm particles.

A condensation-growth and impaction method for rapid off-line chemical-characterization of organic submicrometer atmospheric aerosol particles

2003 ◽  
Vol 34 (2) ◽  
pp. 225-242 ◽  
Author(s):  
Berko Sierau ◽  
Frank Stratmann ◽  
Matthias Pelzing ◽  
Christian Neusüß ◽  
Diana Hofmann ◽  
...  
Keyword(s):  
Atmospheric Aerosol ◽  
Aerosol Particles ◽  
Chemical Characterization ◽  
Atmospheric Aerosol Particles ◽  
Condensation Growth

Measurement of the nucleation of atmospheric aerosol particles

2012 ◽  
Vol 7 (9) ◽  
pp. 1651-1667 ◽  
Author(s):  
Markku Kulmala ◽  
Tuukka Petäjä ◽  
Tuomo Nieminen ◽  
Mikko Sipilä ◽  
Hanna E Manninen ◽  
...  
Keyword(s):  
Atmospheric Aerosol ◽  
Aerosol Particles ◽  
Atmospheric Aerosol Particles
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