Photoenhanced Uptake of NO2 on Mineral Dust

George, Christian; Ndour, Marième; Balkanski, Yves; Ka, Oumar

doi:10.1007/978-1-4020-6429-6_16

Cited by 8 publications

(5 citation statements)

References 12 publications

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“…Although the average γ(NO 2 ) of 7.01 × 10 –5 was obtained for a poorly lit condition, it was much higher than those used in model studies, such as γ(NO 2 ) set to be 1.0 × 10 –6 for night-time in Hong Kong . If the photoenhancing effect is considered, − daytime γ(NO 2 ) on walls and road surfaces would be much higher than 7.01 × 10 –5 under high RH, as in the Guangzhou city where this study was conducted . Therefore, the contribution of NO 2 conversion to HONO on surfaces may be underestimated in urban areas like Guangzhou if a γ(NO 2 ) value of 10 –6 –10 –5 is applied.…”

Section: Resultsmentioning

confidence: 78%

Contribution of Vehicle Emission and NO₂ Surface Conversion to Nitrous Acid (HONO) in Urban Environments: Implications from Tests in a Tunnel

Song

Zhan

et al. 2021

Environ. Sci. Technol.

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Nitrous acid (HONO) is an important photochemical precursor to hydroxyl radicals particularly in an urban atmosphere, yet its primary emission and secondary production are often poorly constrained. Here, we measured HONO and nitrogen oxides (NO x ) at both the inlet and the outlet in a busy urban tunnel (>30 000 vehicles per day) in south China. Multiple linear regression revealed that 73.9% of the inlet–outlet incremental HONO concentration was explained by NO2 surface conversion, while the rest was directly emitted from vehicles with an average HONO/NO x ratio of 1.31 ± 0.87%, which was higher than that from previous tunnel studies. The uptake coefficient of NO2, γ(NO2), on the tunnel surfaces was calculated to be (7.01 ± 0.02) × 10–5, much higher than that widely used in models. As tunnel surfaces are typical of urban surfaces in the wall and road materials, the dominance of HONO from surface reactions in the poorly lit urban tunnel demonstrated the importance of NO2 conversion on urban surfaces, instead of NO2 conversion on the aerosol surface, for both daytime and night-time HONO even in polluted ambient air. The higher γ(NO2) on urban surfaces and the elevated HONO/NO x ratio from this study can help explain the missing HONO sources in urban areas.

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Section: Resultsmentioning

confidence: 78%

Contribution of Vehicle Emission and NO₂ Surface Conversion to Nitrous Acid (HONO) in Urban Environments: Implications from Tests in a Tunnel

Song

Zhan

et al. 2021

Environ. Sci. Technol.

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“…In addition, displacement of deposited nitrite by strong acids generated during photooxidation events are another source of HONO during the daytime . However, these mechanisms depend on sunlight to generate the reductant or the strong acid. − Lee et al proposed that ferrous iron (Fe 2+ ) present in cloudwater could reduce NO 2 , although they concluded that the low Fe 2+ concentrations present in this medium would render this reaction negligible in the troposphere …”

Section: Introductionmentioning

confidence: 99%

The Role of Iron-Bearing Minerals in NO₂ to HONO Conversion on Soil Surfaces

Kebede¹,

Bish²,

Losovyj³

et al. 2016

Environ. Sci. Technol.

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Nitrous acid (HONO) accumulates in the nocturnal boundary layer where it is an important source of daytime hydroxyl radicals. Although there is clear evidence for the involvement of heterogeneous reactions of NO2 on surfaces as a source of HONO, mechanisms remain poorly understood. We used coated-wall flow tube measurements of NO2 reactivity on environmentally relevant surfaces (Fe (hydr)oxides, clay minerals, and soil from Arizona and the Saharan Desert) and detailed mineralogical characterization of substrates to show that reduction of NO2 by Fe-bearing minerals in soil can be a more important source of HONO than the putative NO2 hydrolysis mechanism. The magnitude of NO2-to-HONO conversion depends on the amount of Fe(2+) present in substrates and soil surface acidity. Studies examining the dependence of HONO flux on substrate pH revealed that HONO is formed at soil pH < 5 from the reaction between NO2 and Fe(2+)(aq) present in thin films of water coating the surface, whereas in the range of pH 5-8 HONO stems from reaction of NO2 with structural iron or surface complexed Fe(2+) followed by protonation of nitrite via surface Fe-OH2(+) groups. Reduction of NO2 on ubiquitous Fe-bearing minerals in soil may explain HONO accumulation in the nocturnal boundary layer and the enhanced [HONO]/[NO2] ratios observed during dust storms in urban areas.

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“…In recent years, a number of studies have found that the heterogeneous uptake of NO 2 by organic surfaces is enhanced in the presence of light. [18][19][20][21] In addition, the uptake of ozone onto solid benzophenone films 22 and chlorophyll at the aqueous surface 23 has been shown to be enhanced by the presence of light. These results, coupled with recent measurements of changes in the wettability of solid organic films as a result of photosensitized reaction with ozone, 24 imply that photosensitized processes on aerosol surfaces may influence the lifetime and abundance of a variety of trace gas species and simultaneously alter the physical and chemical properties of the aerosols themselves.…”

Section: Introductionmentioning

confidence: 99%

Photoenhanced ozone loss on solid pyrene films

Styler

Brigante

D’Anna

et al. 2009

Phys. Chem. Chem. Phys.

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This work presents the results of two complementary studies of the heterogeneous reaction of gas-phase ozone with solid pyrene films. In the first study, ozone uptake by the pyrene film was determined using a coated-wall flow tube system. In the second, pyrene loss within the film upon exposure to ozone was monitored using a laser-induced fluorescence technique. The dependence of the reactive loss rate on ozone concentration observed in both methods suggests that the reaction proceeds via a Langmuir-Hinshelwood-type surface mechanism. At a mixing ratio of 50 ppb, the steady-state reactive uptake coefficient of ozone by pyrene films increased from 5.0x10(-6) in the dark to 3.7x10(-5) upon exposure to near-UV radiation (300-420 nm). The uptake coefficient increased linearly as a function of UV-A spectral irradiance and decreased markedly with increasing relative humidity. The loss of surface pyrene upon exposure to ozone also displayed a light enhancement: analysis of Langmuir-Hinshelwood plots for the light and dark reactions revealed a small increase in the two-dimensional reaction rate in the presence of light (lambda>or=295 nm). This modest enhancement, however, was less significant than the corresponding enhancement in the loss of gas-phase ozone. In order to explain these observations, we present an integrated mechanism whereby the light-enhanced ozone uptake arises from the reaction of ozone with O2(1Sigmag+) formed via energy transfer from excited-state pyrene and the enhanced pyrene loss occurs via the formation of a charge-transfer complex between excited-state pyrene and adsorbed ozone. The disparity between surface- and gas-phase results underscores the important role that multifaceted strategies can play in elucidating the mechanisms of heterogeneous atmospheric reactions.

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Photoenhanced Uptake of NO2 on Mineral Dust

Cited by 8 publications

References 12 publications

Contribution of Vehicle Emission and NO₂ Surface Conversion to Nitrous Acid (HONO) in Urban Environments: Implications from Tests in a Tunnel

Contribution of Vehicle Emission and NO₂ Surface Conversion to Nitrous Acid (HONO) in Urban Environments: Implications from Tests in a Tunnel

The Role of Iron-Bearing Minerals in NO₂ to HONO Conversion on Soil Surfaces

Photoenhanced ozone loss on solid pyrene films

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Photoenhanced Uptake of NO2 on Mineral Dust

Cited by 8 publications

References 12 publications

Contribution of Vehicle Emission and NO2 Surface Conversion to Nitrous Acid (HONO) in Urban Environments: Implications from Tests in a Tunnel

Contribution of Vehicle Emission and NO2 Surface Conversion to Nitrous Acid (HONO) in Urban Environments: Implications from Tests in a Tunnel

The Role of Iron-Bearing Minerals in NO2 to HONO Conversion on Soil Surfaces

Photoenhanced ozone loss on solid pyrene films

Contact Info

Product

Resources

About

Contribution of Vehicle Emission and NO₂ Surface Conversion to Nitrous Acid (HONO) in Urban Environments: Implications from Tests in a Tunnel

Contribution of Vehicle Emission and NO₂ Surface Conversion to Nitrous Acid (HONO) in Urban Environments: Implications from Tests in a Tunnel

The Role of Iron-Bearing Minerals in NO₂ to HONO Conversion on Soil Surfaces