Release of Nitrous Acid and Nitrogen Dioxide from Nitrate Photolysis in Acidic Aqueous Solutions

Scharko, Nicole K.; Berke, Andrew E.; Raff, Jonathan D.

doi:10.1021/es503088x

Cited by 129 publications

(219 citation statements)

References 111 publications

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“…We note that, if HONO production is greater than assumed at Dome C, following the recent laboratory study of Scharko et al (2014), this will not change the main conclusions of this study. Indeed, the photolytically produced HONO will be photolyzed to form NO in the atmosphere and this NO would simply enter the NO / NO 2 cycles, where oxygen isotopes are reset.…”

Section: Validation Of the Macroscopic Fluxesmentioning

confidence: 61%

Air–snow transfer of nitrate on the East Antarctic Plateau – Part 2: An isotopic model for the interpretation of deep ice-core records

et al. 2015

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Abstract. Unraveling the modern budget of reactive nitrogen on the Antarctic Plateau is critical for the interpretation of ice-core records of nitrate. This requires accounting for nitrate recycling processes occurring in near-surface snow and the overlying atmospheric boundary layer. Not only concentration measurements but also isotopic ratios of nitrogen and oxygen in nitrate provide constraints on the processes at play. However, due to the large number of intertwined chemical and physical phenomena involved, numerical modeling is required to test hypotheses in a quantitative manner. Here we introduce the model TRANSITS (TRansfer of Atmospheric Nitrate Stable Isotopes To the Snow), a novel conceptual, multi-layer and one-dimensional model representing the impact of processes operating on nitrate at the air-snow interface on the East Antarctic Plateau, in terms of concentrations (mass fraction) and nitrogen (δ 15 N) and oxygen isotopic composition ( 17 O excess, 17 O) in nitrate. At the airsnow interface at Dome C (DC; 75• 06 S, 123• 19 E), the model reproduces well the values of δ 15 N in atmospheric and surface snow (skin layer) nitrate as well as in the δ 15 N profile in DC snow, including the observed extraordinary high positive values (around +300 ‰) below 2 cm. The model also captures the observed variability in nitrate mass fraction in the snow. While oxygen data are qualitatively reproduced at the air-snow interface at DC and in East Antarctica, the simulated 17 O values underestimate the observed 17 O values by several per mill. This is explained by the simplifications made in the description of the atmospheric cycling and oxidation of NO 2 as well as by our lack of understanding of the NO x chemistry at Dome C. The model reproduces well the sensitivity of δ 15 N, 17 O and the apparent fractionation constants ( 15 ε app , 17 E app ) to the snow accumulation rate. Building on this development, we propose a framework for the interpretation of nitrate records measured from ice cores. Measurement of nitrate mass fractions and δ 15 N in the nitrate archived in an ice core may be used to derive information about past variations in the total ozone column and/or the primary inputs of nitrate above Antarctica as well as in nitrate trapping efficiency (defined as the ratio between the archived nitrate flux and the primary nitrate input flux). The 17 O of nitrate could then be corrected from the impact of cage recombination effects associated with the photolysis of nitrate in snow. Past changes in the relative contributions of the 17 O in the primary inputs of nitrate and the 17 O in the locally cycled NO 2 and that inherited from the additional O atom in the oxidation of NO 2 could then be determined. Therefore, information about the past variations in the local and long-range processes operating on reactive nitrogen species could be obtained from ice cores collected in lowaccumulation regions such as the Antarctic Plateau.

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Section: Validation Of the Macroscopic Fluxesmentioning

confidence: 61%

Air–snow transfer of nitrate on the East Antarctic Plateau – Part 2: An isotopic model for the interpretation of deep ice-core records

et al. 2015

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“…In addition to the heterogeneous NO 2 reaction, Bejan et al (2006) observed HONO formation during irradiation of nitrophenols. Photolysis of nitrate or nitric acid generates HONO as well (Baergen and Donaldson, 2013;Scharko et al, 2014;Zhou et al, , 2011. Contrary to the detected missing HONO source near the ground, recent airborne measurements (500-1200 m a.g.l., above ground level) observed HONO concentrations, which could be explained by gas-phase reactions only (Li et al, 2014;Neuman et al, 2016).…”

Section: Introductionmentioning

confidence: 94%

Emission of nitrous acid from soil and biological soil crusts represents an important source of HONO in the remote atmosphere in Cyprus

et al. 2018

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Abstract. Soil and biological soil crusts can emit nitrous acid (HONO) and nitric oxide (NO). The terrestrial ground surface in arid and semiarid regions is anticipated to play an important role in the local atmospheric HONO budget, deemed to represent one of the unaccounted-for HONO sources frequently observed in field studies. In this study HONO and NO emissions from a representative variety of soil and biological soil crust samples from the Mediterranean island Cyprus were investigated under controlled laboratory conditions. A wide range of fluxes was observed, ranging from 0.6 to 264 ng m −2 s −1 HONO-N at optimal soil water content (20-30 % of water holding capacity, WHC). Maximum NO-N fluxes at this WHC were lower (0.8-121 ng m −2 s −1 ). The highest emissions of both reactive nitrogen species were found from bare soil, followed by light and dark cyanobacteria-dominated biological soil crusts (biocrusts), correlating well with the sample nutrient levels (nitrite and nitrate). Extrapolations of lab-based HONO emission studies agree well with the unaccounted-for HONO source derived previously for the extensive CYPHEX field campaign, i.e., emissions from soil and biocrusts may essentially close the Cyprus HONO budget.

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“…In contrast, other recently proposed HONO sources will have a minor contribution. Aqueous solutions in which HONO yields from nitrate photolysis may be enhanced by organics (Scharko et al, 2014) will not be important for the urban conditions investigated in this study as there are no aqueous surfaces in the surrounding area. Recently, in the study of Rutter et al (2014), a gas phase reduction of HNO 3 by VOCs to HONO was proposed.…”

Section: Missing Hono Sourcementioning

confidence: 99%

Detailed budget analysis of HONO in central London reveals a missing daytime source

et al. 2016

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Abstract. Measurements of HONO were carried out at an urban background site near central London as part of the Clean air for London (ClearfLo) project in summer 2012. Data were collected from 22 July to 18 August 2014, with peak values of up to 1.8 ppbV at night and non-zero values of between 0.2 and 0.6 ppbV seen during the day. A wide range of other gas phase, aerosol, radiation, and meteorological measurements were made concurrently at the same site, allowing a detailed analysis of the chemistry to be carried out. The peak HONO / NO x ratio of 0.04 is seen at ∼ 02:00 UTC, with the presence of a second, daytime, peak in HONO / NO x of similar magnitude to the night-time peak, suggesting a significant secondary daytime HONO source. A photostationary state calculation of HONO involving formation from the reaction of OH and NO and loss from photolysis, reaction with OH, and dry deposition shows a significant underestimation during the day, with calculated values being close to 0, compared to the measurement average of 0.4 ppbV at midday. The addition of further HONO sources from the literature, including dark conversion of NO 2 on surfaces, direct emission, photolysis of ortho-substituted nitrophenols, the postulated formation from the reaction of HO 2 × H 2 O with NO 2 , photolysis of adsorbed HNO 3 on ground and aerosols, and HONO produced by photosensitized conversion of NO 2 on the surface increases the daytime modelled HONO to 0.1 ppbV, still leaving a significant missing daytime source. The missing HONO is plotted against a series of parameters including NO 2 and OH reactivity (used as a proxy for organic material), with little correlation seen. Much better correlation is observed with the product of these species with j (NO 2 ), in particular NO 2 and the product of NO 2 with OH reactivity. This suggests the missing HONO source is in some way related to NO 2 and also requires sunlight. Increasing the photosensitized surface conversion rate of NO 2 by a factor of 10 to a mean daytime first-order loss of ∼ 6 ×10 −5 s −1 (but which varies as a function of j (NO 2 )) closes the daytime HONO budget at all times (apart from the late afternoon), suggesting that urban surfaces may enhance this photosensitized source. The effect of the missing HONO to OH radical production is also investigated and it is shown that the model needs to be constrained to measured HONO in order to accurately reproduce the OH radical measurements.

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Release of Nitrous Acid and Nitrogen Dioxide from Nitrate Photolysis in Acidic Aqueous Solutions

Cited by 129 publications

References 111 publications

Air–snow transfer of nitrate on the East Antarctic Plateau – Part 2: An isotopic model for the interpretation of deep ice-core records

Air–snow transfer of nitrate on the East Antarctic Plateau – Part 2: An isotopic model for the interpretation of deep ice-core records

Emission of nitrous acid from soil and biological soil crusts represents an important source of HONO in the remote atmosphere in Cyprus

Detailed budget analysis of HONO in central London reveals a missing daytime source

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