Uptake of HO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; radicals on Arizona Test Dust

Bedjanian, Yuri; Romanías, Manolis N.; Zein, Atallah El

doi:10.5194/acp-13-6461-2013

Cited by 35 publications

(49 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although the true mechanism for reaction at the surface remains unclear, the large rate coefficient for this reaction suggests that copper could potentially be catalysing the destruction of HO 2 at the surface of the sucrose particles, which is consistent with the higher HO 2 uptake coefficients measured on solid aerosol particles containing transition metals compared to solid aerosol particles containing no transition metal ions (Matthews et al, 2014;Lakey et al, 2015a;Bedjanian et al, 2013;George et al, 2013). Note however that for a relevant surface reaction in kinetic flux models, it is necessary to use an effective desorption lifetime, τ d , in the millisecond to second time range Shiraiwa et al, 2010).…”

Section: Ho 2 Uptake By Copper-doped Sucrose Aerosol Particlessupporting

confidence: 73%

The effect of viscosity and diffusion on the HO<sub>2</sub> uptake by sucrose and secondary organic aerosol particles

et al. 2016

View full text Add to dashboard Cite

Abstract. We report the first measurements of HO 2 uptake coefficients, γ , for secondary organic aerosol (SOA) particles and for the well-studied model compound sucrose which we doped with copper(II). Above 65 % relative humidity (RH), γ for copper(II)-doped sucrose aerosol particles equalled the surface mass accommodation coefficient α = 0.22 ± 0.06, but it decreased to γ = 0.012 ± 0.007 upon decreasing the RH to 17 %. The trend of γ with RH can be explained by an increase in aerosol viscosity and the contribution of a surface reaction, as demonstrated using the kinetic multilayer model of aerosol surface and bulk chemistry (KM-SUB). At high RH the total uptake was driven by reaction in the near-surface bulk and limited by mass accommodation, whilst at low RH it was limited by surface reaction. SOA from two different precursors, α-pinene and 1,3,5-trimethylbenzene (TMB), was investigated, yielding low uptake coefficients of γ < 0.001 and γ = 0.004 ± 0.002, respectively. It is postulated that the larger values measured for TMB-derived SOA compared to α-pinene-derived SOA are either due to differing viscosity, a different liquid water content of the aerosol particles, or an HO 2 + RO 2 reaction occurring within the aerosol particles.

show abstract

Section: Ho 2 Uptake By Copper-doped Sucrose Aerosol Particlessupporting

confidence: 73%

The effect of viscosity and diffusion on the HO<sub>2</sub> uptake by sucrose and secondary organic aerosol particles

et al. 2016

View full text Add to dashboard Cite

show abstract

“…Figure 2 suggests that when the TiO 2 sample mass is < 0.15 mg cm −1 , the projected-area-based uptake coefficients depend linearly on the sample mass. If measurements are carried out within the LMD regime, surfaces of all the particles are available for heterogeneous uptake and the BET surface area should be used to calculate uptake coefficients Romanias et al, 2012a;Bedjanian et al, 2013a).…”

Section: Surface Area Available For Heterogeneous Uptakementioning

confidence: 99%

Heterogeneous reactions of mineral dust aerosol: implications for tropospheric oxidation capacity

et al. 2017

View full text Add to dashboard Cite

Abstract. Heterogeneous reactions of mineral dust aerosol with trace gases in the atmosphere could directly and indirectly affect tropospheric oxidation capacity, in addition to aerosol composition and physicochemical properties. In this article we provide a comprehensive and critical review of laboratory studies of heterogeneous uptake of OH, NO 3 , O 3 , and their directly related species as well (including HO 2 , H 2 O 2 , HCHO, HONO, and N 2 O 5 ) by mineral dust particles. The atmospheric importance of heterogeneous uptake as sinks for these species is assessed (i) by comparing their lifetimes with respect to heterogeneous reactions with mineral dust to lifetimes with respect to other major loss processes and (ii) by discussing relevant field and modeling studies. We have also outlined major open questions and challenges in laboratory studies of heterogeneous uptake by mineral dust and discussed research strategies to address them in order to better understand the effects of heterogeneous reactions with mineral dust on tropospheric oxidation capacity.

show abstract

“…In the conventional manner, a lower limit for j het was obtained by assuming that the whole sample surface is active at nucleating ice. For Hoggar Mountain dust and ATD, the available surface area per sample was calculated based on the mass present in the sample and the BET (Brunauer-Emmett-Teller) surface area, namely 46.3 m 2 g −1 for Hoggar Mountain dust (Pinti et al, 2012) and 85 m 2 g −1 for the ATD sample (Bedjanian et al, 2013).…”

Section: Hoggar Mountain Dust and Atdmentioning

confidence: 99%

Refreeze experiments with water droplets containing different types of ice nuclei interpreted by classical nucleation theory

et al. 2017

View full text Add to dashboard Cite

Abstract. Homogeneous nucleation of ice in supercooled water droplets is a stochastic process. In its classical description, the growth of the ice phase requires the emergence of a critical embryo from random fluctuations of water molecules between the water bulk and ice-like clusters, which is associated with overcoming an energy barrier. For heterogeneous ice nucleation on ice-nucleating surfaces both stochastic and deterministic descriptions are in use. Deterministic (singular) descriptions are often favored because the temperature dependence of ice nucleation on a substrate usually dominates the stochastic time dependence, and the ease of representation facilitates the incorporation in climate models. Conversely, classical nucleation theory (CNT) describes heterogeneous ice nucleation as a stochastic process with a reduced energy barrier for the formation of a critical embryo in the presence of an ice-nucleating surface. The energy reduction is conveniently parameterized in terms of a contact angle α between the ice phase immersed in liquid water and the heterogeneous surface. This study investigates various ice-nucleating agents in immersion mode by subjecting them to repeated freezing cycles to elucidate and discriminate the time and temperature dependences of heterogeneous ice nucleation. Freezing rates determined from such refreeze experiments are presented for Hoggar Mountain dust, birch pollen washing water, Arizona test dust (ATD), and also nonadecanol coatings. For the analysis of the experimental data with CNT, we assumed the same active site to be always responsible for freezing. Three different CNT-based parameterizations were used to describe rate coefficients for heterogeneous ice nucleation as a function of temperature, all leading to very similar results: for Hoggar Mountain dust, ATD, and larger nonadecanol-coated water droplets, the experimentally determined increase in freezing rate with decreasing temperature is too shallow to be described properly by CNT using the contact angle α as the only fit parameter. Conversely, birch pollen washing water and small nonadecanol-coated water droplets show temperature dependencies of freezing rates steeper than predicted by all three CNT parameterizations. Good agreement of observations and calculations can be obtained when a pre-factor β is introduced to the rate coefficient as a second fit parameter. Thus, the following microphysical picture emerges: heterogeneous freezing occurs at ice-nucleating sites that need a minimum (critical) surface area to host embryos of critical size to grow into a crystal. Fits based on CNT suggest that the critical active site area is in the range of 10-50 nm 2 , with the exact value depending on sample, temperature, and CNT-based parameterization. Two fitting parameters are needed to characterize individual active sites. The contact angle α lowers the energy barrier that has to be overcome to form the critical embryo at the site compared to the homogeneous case where the critical embryo develops in the volume of water....

show abstract

Uptake of HO<sub>2</sub> radicals on Arizona Test Dust

Cited by 35 publications

References 38 publications

The effect of viscosity and diffusion on the HO<sub>2</sub> uptake by sucrose and secondary organic aerosol particles

The effect of viscosity and diffusion on the HO<sub>2</sub> uptake by sucrose and secondary organic aerosol particles

Heterogeneous reactions of mineral dust aerosol: implications for tropospheric oxidation capacity

Refreeze experiments with water droplets containing different types of ice nuclei interpreted by classical nucleation theory

Contact Info

Product

Resources

About

Uptake of HO&lt;sub&gt;2&lt;/sub&gt; radicals on Arizona Test Dust

Cited by 35 publications

References 38 publications

The effect of viscosity and diffusion on the HO&lt;sub&gt;2&lt;/sub&gt; uptake by sucrose and secondary organic aerosol particles

The effect of viscosity and diffusion on the HO&lt;sub&gt;2&lt;/sub&gt; uptake by sucrose and secondary organic aerosol particles

Heterogeneous reactions of mineral dust aerosol: implications for tropospheric oxidation capacity

Refreeze experiments with water droplets containing different types of ice nuclei interpreted by classical nucleation theory

Contact Info

Product

Resources

About

Uptake of HO<sub>2</sub> radicals on Arizona Test Dust

The effect of viscosity and diffusion on the HO<sub>2</sub> uptake by sucrose and secondary organic aerosol particles

The effect of viscosity and diffusion on the HO<sub>2</sub> uptake by sucrose and secondary organic aerosol particles