Heterogeneous uptake of NO2 on Arizona Test Dust under UV-A irradiation: An aerosol flow tube study

Dupart, Y.; Fine, L.; D’Anna, Barbara; George, Christian

doi:10.1016/j.aeolia.2013.10.001

Cited by 25 publications

(36 citation statements)

References 43 publications

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“…For example, as noted by Park and Jang (2016), the reactive uptake coefficient (γ SO 1 order of magnitude higher (1.16 × 10 −6 using an indoor chamber with a light mix of UV-A and UV-B light) than that from autoxidation (1.15 × 10 −7 ) without a light source. Using an aerosol flow tube, Dupart et al (2014) observed that the uptake rate of NO 2 by ATD dust particles was significantly enhanced (by 4 times) under UV-A irradiation compared to dark conditions. Field observations have also reported the promotion of SO 2 photooxidation in the presence of mineral dust.…”

Section: Introductionmentioning

confidence: 99%

“…Semiconducting metal oxides (e.g., α-Al 2 O 3 , α-Fe 2 O 3 , and TiO 2 ) act as a photocatalyst in mineral dust particles that can yield electron (e − cb )-hole (h + vb ) pairs, and that they are involved in the production of strong oxidizers, such as superoxide radical anions (O − 2 ) and OH radicals (Linsebigler et al, 1995;Hoffmann et al, 1995;Thompson and Yates, 2006;Cwiertny et al, 2008;Chen et al, 2012;Dupart et al, 2014;Colmenares and Luque, 2014). These oxidizers enable rapid oxidation of adsorbed SO 2 and NO x on the surface of mineral dust particles.…”

Section: Introductionmentioning

confidence: 99%

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Modeling atmospheric mineral aerosol chemistry to predict heterogeneous photooxidation of SO2

Jang

Park

2017

Atmos. Chem. Phys.

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Abstract. The photocatalytic ability of airborne mineral dust particles is known to heterogeneously promote SO 2 oxidation, but prediction of this phenomenon is not fully taken into account by current models. In this study, the Atmospheric Mineral Aerosol Reaction (AMAR) model was developed to capture the influence of air-suspended mineral dust particles on sulfate formation in various environments. In the model, SO 2 oxidation proceeds in three phases including the gas phase, the inorganic-salted aqueous phase (non-dust phase), and the dust phase. Dust chemistry is described as the absorption-desorption kinetics of SO 2 and NO x (partitioning between the gas phase and the multilayer coated dust). The reaction of absorbed SO 2 on dust particles occurs via two major paths: autoxidation of SO 2 in open air and photocatalytic mechanisms under UV light. The kinetic mechanism of autoxidation was first leveraged using controlled indoor chamber data in the presence of Arizona Test Dust (ATD) particles without UV light, and then extended to photochemistry. With UV light, SO 2 photooxidation was promoted by surface oxidants (OH radicals) that are generated via the photocatalysis of semiconducting metal oxides (electron-hole theory) of ATD particles. This photocatalytic rate constant was derived from the integration of the combinational product of the dust absorbance spectrum and wave-dependent actinic flux for the full range of wavelengths of the light source. The predicted concentrations of sulfate and nitrate using the AMAR model agreed well with outdoor chamber data that were produced under natural sunlight. For seven consecutive hours of photooxidation of SO 2 in an outdoor chamber, dust chemistry at the low NO x level was attributed to 55 % of total sulfate (56 ppb SO 2 , 290 µg m −3 ATD, and NO x less than 5 ppb). At high NO x (> 50 ppb of NO x with low hydrocarbons), sulfate formation was also greatly promoted by dust chemistry, but it was suppressed by the competition between NO 2 and SO 2 , which both consume the dust-surface oxidants (OH radicals or ozone).

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Modeling atmospheric mineral aerosol chemistry to predict heterogeneous photooxidation of SO2

Jang

Park

2017

Atmos. Chem. Phys.

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“…For example, as noted by Park and Jang (2016), the reactive uptake coefficient ( 4 2−) of SO2 in the presence of dry Arizona Test Dust (ATD) particles under UV light was one order of magnitude higher (1.16 × 10 -6 using an indoor chamber with a light mix of UV-A and UV-B light) than that from autoxidation (1.15 × 10 -7 ) without a light source. Using an aerosol flow tube, Dupart et al (2014) observed that the uptake rate of NO2 by ATD dust particles was significantly enhanced 20 (by four times) under UV-A irradiation compared to dark conditions. Field observations have also reported the promotion of SO2 photooxidation in the presence of mineral dust.…”

Section: Introductionmentioning

confidence: 98%

“…25 Semiconducting metal oxides (e.g. α-Al2O3, α-Fe2O3, and TiO2) act as a photocatalyst in mineral dust particles that can yield electron (ecb)-hole (h + vb) pairs, and that they are involved in the production of strong oxidizers, such as superoxide radical anions (O2 − ) and OH radicals (Linsebigler et al, 1995;Hoffmann et al, 1995;Thompson and Yates, 2006;Cwiertny et al, 2008;Chen et al, 2012;Dupart et al, 2014;Colmenares and Luque, 2014). These oxidizers enable rapid 30 oxidation of adsorbed SO2 and NOx on the surface of mineral dust particles.…”

Section: Introductionmentioning

confidence: 99%

Modelling Atmospheric Mineral Aerosol Chemistry to Predict Heterogeneous Photooxidation of SO2

Yu¹,

Jang²,

Park³

2017

Preprint

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Abstract. The photocatalytic ability of airborne mineral dust particles is known to heterogeneously promote SO2 oxidation, but prediction of this phenomenon is not fully taken into account by current models. In this study, the Atmospheric Mineral Aerosol Reaction (AMAR) model was developed to capture the influence of air-suspended mineral dust particles on sulfate formation in various environments. In the model, SO2 oxidation proceeds in three phases including the gas phase, the inorganic-salted aqueous phase (non-dust phase), and the dust phase. Dust chemistry is described as the adsorption-desorption kinetics (gas-particle partitioning) of SO2 and NOx. The reaction of adsorbed SO2 on dust particles occurs via two major paths: autoxidation of SO2 in open air and photocatalytic mechanisms under UV light. The kinetic mechanism of autoxidation was first leveraged using controlled indoor chamber data in the presence of Arizona Test Dust (ATD) particles without UV light, and then extended to photochemistry. With UV light, SO2 photooxidation was promoted by surface oxidants (OH radicals) that are generated via the photocatalysis of semiconducting metal oxides (electron&#8211;hole theory) of ATD particles. This photocatalytic rate constant was derived from the integration of the combinational product of the dust absorbance spectrum and wave-dependent actinic flux for the full range of wavelengths of the light source. The predicted concentrations of sulfate and nitrate using the AMAR model agreed well with outdoor chamber data that were produced under natural sunlight. For seven consecutive hours of photooxidation of SO2 in an outdoor chamber, dust chemistry at the low NOx level was attributed to 70&#8201;% of total sulfate (60&#8201;ppb&#8201;SO2, 290&#8201;&#956;g&#8201;m&#8722;3 ATD, and NOx less than 5&#8201;ppb). At high NOx (>&#8201;50&#8201;ppb of NOx with low hydrocarbons), sulfate formation was also greatly promoted by dust chemistry, but it was significantly suppressed by the competition between NO2 and SO2 that both consume the dust-surface oxidants (OH radicals or ozone). The AMAR model, derived in this study with ATD particles, will provide a platform for predicting sulfate formation in the presence of authentic dust particles (e.g. Gobi and Saharan dust).

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“…The surface of mineral dust particles can act as an important sink for atmospheric trace gases, such as O 3 , NO x (e.g., NO and NO 2 ), and SO 2 , and can enhance the production of oxygenated compounds (e.g., nitrate and sulfate) (Underwood et al, 2001;Michel et al, 2002;Usher et al, 2003b; Published by Copernicus Publications on behalf of the European Geosciences Union. Crowley et al, 2010;George et al, 2015;Tang et al, 2017). For example, 50 % to 70 % of the annual average total sulfate concentration is estimated to be formed by the heterogeneous oxidation of SO 2 in the vicinity of dust sources (Dentener et al, 1996;Usher et al, 2003a).…”

Section: Introductionmentioning

confidence: 99%

Simulation of heterogeneous photooxidation of SO2 and NOx in the presence of Gobi Desert dust particles under ambient sunlight

Jang

2018

Atmos. Chem. Phys.

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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.

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Heterogeneous uptake of NO2 on Arizona Test Dust under UV-A irradiation: An aerosol flow tube study

Cited by 25 publications

References 43 publications

Modeling atmospheric mineral aerosol chemistry to predict heterogeneous photooxidation of SO<sub>2</sub>

Modeling atmospheric mineral aerosol chemistry to predict heterogeneous photooxidation of SO<sub>2</sub>

Modelling Atmospheric Mineral Aerosol Chemistry to Predict Heterogeneous Photooxidation of SO<sub>2</sub>

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

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Heterogeneous uptake of NO2 on Arizona Test Dust under UV-A irradiation: An aerosol flow tube study

Cited by 25 publications

References 43 publications

Modeling atmospheric mineral aerosol chemistry to predict heterogeneous photooxidation of SO&lt;sub&gt;2&lt;/sub&gt;

Modeling atmospheric mineral aerosol chemistry to predict heterogeneous photooxidation of SO&lt;sub&gt;2&lt;/sub&gt;

Modelling Atmospheric Mineral Aerosol Chemistry to Predict Heterogeneous Photooxidation of SO&lt;sub&gt;2&lt;/sub&gt;

Simulation of heterogeneous photooxidation of SO&lt;sub&gt;2&lt;/sub&gt; and NO&lt;sub&gt;&lt;i&gt;x&lt;/i&gt;&lt;/sub&gt; in the presence of Gobi Desert dust particles under ambient sunlight

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Modeling atmospheric mineral aerosol chemistry to predict heterogeneous photooxidation of SO<sub>2</sub>

Modeling atmospheric mineral aerosol chemistry to predict heterogeneous photooxidation of SO<sub>2</sub>

Modelling Atmospheric Mineral Aerosol Chemistry to Predict Heterogeneous Photooxidation of SO<sub>2</sub>

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