Heterogeneous chemistry of individual mineral dust particles with nitric acid: A combined CCSEM/EDX, ESEM, and ICP-MS study

2005 ◽  
Vol 110 (D10) ◽  
Author(s):  
A. Laskin
Keyword(s):  
Nitric Acid ◽  
Mineral Dust ◽  
Dust Particles ◽  
Heterogeneous Chemistry ◽  
Icp Ms

scholarly journals Simulation of heterogeneous photooxidation of SO<sub>2</sub> and NO<sub><i>x</i></sub> in the presence of Gobi Desert dust particles under ambient sunlight

2018 ◽  
Vol 18 (19) ◽  
pp. 14609-14622 ◽  
Author(s):  
Zechen Yu ◽  
Myoseon Jang
Keyword(s):  
Urban Areas ◽  
Mineral Dust ◽  
Buffering Capacity ◽  
Dust Particles ◽  
Gobi Desert ◽  
Heterogeneous Chemistry ◽  
Desert Dust ◽  
Malachite Green Dye ◽  
Photodegradation Rate ◽  
Nitrate Salts

Abstract. To improve the simulation of the heterogeneous oxidation of SO2 and NOx in the presence of authentic mineral dust particles under ambient environmental conditions, the explicit kinetic mechanisms were constructed in the Atmospheric Mineral Aerosol Reaction (AMAR) model. The formation of sulfate and nitrate was divided into three phases: the gas phase, the non-dust aqueous phase, and the dust phase. In particular, AMAR established the mechanistic role of dust chemical characteristics (e.g., photoactivation, hygroscopicity, and buffering capacity) in heterogeneous chemistry. The photoactivation kinetic process of different dust particles was built into the model by measuring the photodegradation rate constant of an impregnated surrogate (malachite green dye) on a dust filter sample (e.g., Arizona test dust – ATD – and Gobi Desert dust – GDD) using an online reflective UV–visible spectrometer. The photoactivation parameters were integrated with the heterogeneous chemistry to predict the formation of reactive oxygen species on dust surfaces. A mathematical equation for the hygroscopicity of dust particles was also included in the AMAR model to process the multiphase partitioning of trace gases and in-particle chemistry. The buffering capacity of dust, which is related to the neutralization of dust alkaline carbonates with inorganic acids, was included in the model to dynamically predict the hygroscopicity of aged dust. The AMAR model simulated the formation of sulfate and nitrate using experimental data obtained in the presence of authentic mineral dust under ambient sunlight using a large outdoor smog chamber (University of Florida Atmospheric Photochemical Outdoor Reactor, UF-APHOR). Overall, the influence of GDD on the heterogeneous chemistry was much greater than that of ATD. Based on the model analysis, GDD enhanced the sulfate formation mainly via its high photoactivation capability. In the case of NO2 oxidation, dust-phase nitrate formation is mainly regulated by the buffering capacity of dust. The measured buffering capacity of GDD was 2 times greater than that of ATD, and consequently, the maximum nitrate concentration with GDD was nearly 2 times higher than that with ATD. The model also highlights that in urban areas with high NOx concentrations, hygroscopic nitrate salts quickly form via titration of the carbonates in the dust particles, but in the presence of SO2, the nitrate salts are gradually depleted by the formation of sulfate.

Kinetics of the heterogeneous reaction of nitric acid with mineral dust particles: an aerosol flowtube study

2009 ◽  
Vol 11 (36) ◽  
pp. 7921 ◽  
Author(s):  
A. Vlasenko ◽  
T. Huthwelker ◽  
H. W. Gäggeler ◽  
M. Ammann
Keyword(s):  
Nitric Acid ◽  
Mineral Dust ◽  
Heterogeneous Reaction ◽  
Dust Particles ◽  
Kinetics Of

scholarly journals Simulation of Heterogeneous Photooxidation of SO<sub>2</sub> and NO<sub>x</sub> in the presence of Gobi Desert Dust Particles under Ambient Sunlight

2018 ◽  
Author(s):  
Zechen Yu ◽  
Myoseon Jang
Keyword(s):  
Urban Areas ◽  
Mineral Dust ◽  
Kinetic Mechanism ◽  
Buffering Capacity ◽  
Dust Particles ◽  
Gobi Desert ◽  
Heterogeneous Chemistry ◽  
Desert Dust ◽  
Photodegradation Rate ◽  
Nitrate Salts

Abstract. To improve the simulation of the heterogeneous oxidation of SO2 and NOx in the presence of authentic mineral dust particles under ambient environmental conditions, the explicit kinetic mechanism was constructed in Atmospheric Mineral Aerosol Reaction (AMAR) model. The formation of sulfate and nitrate was divided into three phases: gas phase, non-dust aqueous phase and dust phase. Specially, AMAR established the mechanistic role of dust chemical characteristics (e.g., photoactivation, hygroscopicity, and buffering capacity) on heterogeneous chemistry. The photo-activation kinetic process of different dust particles was built into the model by measuring the photodegradation rate constant of an impregnated surrogate (malachite green dye) on a dust filter sample (e.g., Arizona Test dust (ATD) and Gobi Desert dust (GDD)) using an online reflective UV-visible spectrometer. The photoactivation parameters were integrated with the heterogeneous chemistry to predict OH radical formation on dust surfaces. A mathematical equation for the hygroscopicity of dust particles was also included in the AMAR model to process the multiphase partitioning of tracers and in-particle chemistry. The buffering capacity of dust, which is related to the neutralization of dust alkaline carbonates with inorganic acids, was included in the model to dynamically predict the hygroscopicity of aged dust. The AMAR model simulated the formation of sulfate and nitrate using experimental data obtained in the presence of authentic mineral dust under ambient sunlight using a large outdoor smog chamber (UF-APHOR). Overall, both GDD and ATD significantly enhanced the formation of sulfate and nitrate, compared to that in the system without dust particles. However, the influence of GDD on the heterogeneous chemistry was much greater than that of ATD. Based on the model analysis, GDD enhanced the sulfate formation mainly via its high photoactivation capability. In the case of NO2 oxidation, dust-phase nitrate formation is mainly regulated by the buffering capacity of dust. The measured buffering capacity of GDD was two times greater than that of ATD, and consequently, the maximum nitrate concentration with GDD was nearly two times higher than that with ATD. The model also highlights that in urban areas with high NOx concentrations, hygroscopic nitrate salts quickly form via titration of the carbonates in the dust phase, but in the presence of SO2, the nitrate salts are gradually depleted by sulfate.

Soluble/insoluble fractionation of elements in mineral dust from Antarctic samples

2020 ◽  
Author(s):  
Elena Di Stefano ◽  
Giovanni Baccolo ◽  
Paolo Gabrielli ◽  
Aja Ellis ◽  
Barbara Delmonte ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Mineral Dust ◽  
Ice Core ◽  
Ice Cores ◽  
Dust Particles ◽  
Aeolian Dust ◽  
The Past ◽  
Icp Ms

&lt;p&gt;Deposition of dust on the Antarctic continent is controlled by many factors, such as the primary supply of dust particles from the continents [1], the long range transport, the hydrological cycle and the snow accumulation rate [2, 3]. Thus, the study of mineral dust in ice cores gives the possibility to reconstruct past climatic and environmental conditions.&lt;/p&gt;&lt;p&gt;Generally, when an ice core sample is melted, soluble elements dissolve in water, while insoluble elements remain in the solid phase. Other elements, such as iron, calcium, potassium and sulfur, typically partition between the soluble and the insoluble fractions. However recent studies have shown how the dust record may be chemically and physically altered in deep ice cores [4, 5], posing a challenge in the interpretation of the climatic signal that may lie within such samples. In particular, relative abundance of specific elements was shown to be different when comparing shallow and deep dust samples, suggesting that post depositional processes are taking place.&lt;/p&gt;&lt;p&gt;In this study we present a comparison between samples belonging to the Talos Dome ice core analyzed through two different techniques: instrumental neutron activation analysis (INAA) and inductively coupled plasma mass spectrometry (ICP-MS). While the former is used to investigate only the insoluble fraction of dust, as it can only be applied to solid samples, the latter is used to assess the elemental composition of both the total and the soluble fraction of dust. We determined 45 elements through ICP-MS and 39 through INAA, with a good overlapping of the elements between the two techniques. Besides the determination of major elements, the high sensibility of both techniques also permitted the determination of trace elements. Among these, rare earth elements (REE) are of particular importance as they have been widely used as a geochemical tracer of aeolian dust sources [6]. We here present depth profiles for each analysed element, covering discrete portions of the entire ice core.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;Bibliography&lt;/p&gt;&lt;p&gt;[1] Petit, Jean-Robert, et al. &quot;Climate and atmospheric history of the past 420,000 years from the Vostok ice core, Antarctica.&quot; Nature 399.6735 (1999): 429-436.&lt;/p&gt;&lt;p&gt;[2] Lambert, Fabrice, et al. &quot;Dust-climate couplings over the past 800,000 years from the EPICA Dome C ice core.&quot; Nature 452.7187 (2008): 616.&lt;/p&gt;&lt;p&gt;[3] Wegner, Anna, et al. &quot;The role of seasonality of mineral dust concentration and size on glacial/interglacial dust changes in the EPICA Dronning Maud Land ice core.&quot; Journal of Geophysical Research: Atmospheres 120.19 (2015): 9916-9931.&lt;/p&gt;&lt;p&gt;[4] Baccolo, Giovanni, et al. &amp;#8220;The contribution of synchrotron light for the characterization of atmospheric mineral dust in deep ice cores: Preliminary results from the Talos Dome ice core (East Antarctica).&amp;#8221; Condensed Matter 3, no. 3 (2018): 25.&lt;/p&gt;&lt;p&gt;[5] De Angelis, Martine, et al. &amp;#8220;Micro-investigation of EPICA Dome C bottom ice: Evidence of long term in situ processes involving acid-salt interactions, mineral dust, and organic matter.&amp;#8221; Quaternary Science Reviews 78 (2013): 248-265.&lt;/p&gt;&lt;p&gt;[6] Gabrielli, Paolo, et al. &amp;#8220;A major glacial-interglacial change in aeolian dust composition inferred from Rare Earth Elements in Antarctic ice.&amp;#8221; Quaternary Science Reviews 29, no. 1-2 (2010): 265-273.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;&amp;#160;&lt;/strong&gt;&lt;/p&gt;

scholarly journals Effect of humidity on nitric acid uptake to mineral dust aerosol particles

2005 ◽  
Vol 5 (6) ◽  
pp. 11821-11860 ◽  
Author(s):  
A. Vlasenko ◽  
S. Sjogren ◽  
E. Weingartner ◽  
K. Stemmler ◽  
H. W. Gäggeler ◽  
...  
Keyword(s):  
Nitric Acid ◽  
Reaction Time ◽  
Surface Area ◽  
Flow Reactor ◽  
Mineral Dust ◽  
Water Soluble ◽  
Dust Particles ◽  
Acid Uptake ◽  
Laboratory Observation ◽  
Powder Samples

Abstract. This study presents the first laboratory observation of HNO3 uptake by airborne mineral dust particles. The model aerosols were generated by dry dispersion of Arizona Test Dust (ATD), SiO2, and by nebulizing a saturated solution of calcium carbonate. The uptake of 13N-labelled gaseous nitric acid was observed in a flow reactor on the 0.2–2 s reaction time scale at room temperature and atmospheric pressure. The amount of reacted nitric acid was found to be a linear function of aerosol surface area. SiO2 particles did not show any significant uptake, while the CaCO3 aerosol was found to be more reactive than the ATD. Due to the smaller uncertainty associated with the reactive surface area in the case of suspended particles as compared to bulk powder samples, we believe that we provide an improved estimate of the uptake kinetics of HNO3 to mineral dust. The uptake coefficient averaged over the first 2 s of reaction time at a concentration of 1012 molecules cm−3 was found to increase with increasing relative humidity, from 0.022±0.007 at 12% RH to 0.113±0.017 at 73% RH , scaling along a water adsorption isotherm. The processing of the dust at 85% RH leads to a water soluble coating on the particles and enhances their hygroscopicity.

scholarly journals Effect of humidity on nitric acid uptake to mineral dust aerosol particles

2006 ◽  
Vol 6 (8) ◽  
pp. 2147-2160 ◽  
Author(s):  
A. Vlasenko ◽  
S. Sjogren ◽  
E. Weingartner ◽  
K. Stemmler ◽  
H. W. Gäggeler ◽  
...  
Keyword(s):  
Nitric Acid ◽  
Reaction Time ◽  
Surface Area ◽  
Flow Reactor ◽  
Mineral Dust ◽  
Water Soluble ◽  
Dust Particles ◽  
Acid Uptake ◽  
Uptake Mechanism ◽  
Laboratory Observation

Abstract. This study presents the first laboratory observation of HNO3 uptake by airborne mineral dust particles. The model aerosols were generated by dry dispersion of Arizona Test Dust (ATD), SiO2, and by nebulizing a saturated solution of calcium carbonate. The uptake of 13N-labeled gaseous nitric acid was observed in a flow reactor on the 0.2–2 s reaction time scale at room temperature and atmospheric pressure. The amount of nitric acid appearing in the aerosol phase at the end of the flow tube was found to be a linear function of the aerosol surface area. SiO2 particles did not show any significant uptake, while the CaCO3 aerosol was found to be more reactive than ATD. Due to the smaller uncertainty associated with the reactive surface area in the case of suspended particles as compared to bulk powder samples, we believe that we provide an improved estimate of the rate of uptake of HNO3 to mineral dust. The fact that the rate of uptake was smaller at a concentration of 1012 than at 1011 was indicative of a complex uptake mechanism. The uptake coefficient averaged over the first 2 s of reaction time at a concentration of 1012 molecules cm-3 was found to increase with increasing relative humidity, from 0.022±0.007 at 12% RH to 0.113±0.017 at 73% RH , which was attributed to an increasing degree of solvation of the more basic minerals. The extended processing of the dust by higher concentrations of HNO3 at 85% RH led to a water soluble coating on the particles and enhanced their hygroscopicity.

A Knudsen Cell Study of the Heterogeneous Reactivity of Nitric Acid on Oxide and Mineral Dust Particles

2001 ◽  
Vol 105 (27) ◽  
pp. 6609-6620 ◽  
Author(s):  
G. M. Underwood ◽  
P. Li ◽  
H. Al-Abadleh ◽  
V. H. Grassian
Keyword(s):  
Nitric Acid ◽  
Mineral Dust ◽  
Knudsen Cell ◽  
Dust Particles ◽  
Heterogeneous Reactivity ◽  
Cell Study

scholarly journals Aerosol optical depth retrievals at the Izaña Atmospheric Observatory from 1941 to 2013 by using artificial neural networks

2016 ◽  
Vol 9 (1) ◽  
pp. 53-62 ◽  
Author(s):  
R. D. García ◽  
O. E. García ◽  
E. Cuevas ◽  
V. E. Cachorro ◽  
A. Barreto ◽  
...  
Keyword(s):  
Neural Networks ◽  
Time Series ◽  
Artificial Neural Networks ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Mineral Dust ◽  
Dust Particles ◽  
Filter Radiometer ◽  
Artificial Neural

Abstract. This paper presents the reconstruction of a 73-year time series of the aerosol optical depth (AOD) at 500 nm at the subtropical high-mountain Izaña Atmospheric Observatory (IZO) located in Tenerife (Canary Islands, Spain). For this purpose, we have combined AOD estimates from artificial neural networks (ANNs) from 1941 to 2001 and AOD measurements directly obtained with a Precision Filter Radiometer (PFR) between 2003 and 2013. The analysis is limited to summer months (July–August–September), when the largest aerosol load is observed at IZO (Saharan mineral dust particles). The ANN AOD time series has been comprehensively validated against coincident AOD measurements performed with a solar spectrometer Mark-I (1984–2009) and AERONET (AErosol RObotic NETwork) CIMEL photometers (2004–2009) at IZO, obtaining a rather good agreement on a daily basis: Pearson coefficient, R, of 0.97 between AERONET and ANN AOD, and 0.93 between Mark-I and ANN AOD estimates. In addition, we have analysed the long-term consistency between ANN AOD time series and long-term meteorological records identifying Saharan mineral dust events at IZO (synoptical observations and local wind records). Both analyses provide consistent results, with correlations  >  85 %. Therefore, we can conclude that the reconstructed AOD time series captures well the AOD variations and dust-laden Saharan air mass outbreaks on short-term and long-term timescales and, thus, it is suitable to be used in climate analysis.

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