Characterization of a chemical amplifier for peroxy radical measurements in the atmosphere

Duncianu, Marius; Lahib, Ahmad; Tomás, A.; Stevens, P. S.; Dusanter, Sébastien

doi:10.1016/j.atmosenv.2019.117106

Cited by 11 publications

(12 citation statements)

References 58 publications

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“…In the first chemical amplification instruments, NO2 was detected by luminol chemiluminescence, which has a non-linear response to NO2 resulting in the need for a multipoint calibration (Cantrell et al, 1997). However, more recent instruments use cavity absorption phase shift (CAPS) (Duncianu et al, 2020;Wood and Charest, 2014), laser induced fluorescence (LIF) (Sadanaga et al, 2004), or cavity ring-down spectroscopy (CRDS) (Liu and Zhang, 2014) for detection of NO2, all of which have been shown to have a linear response.…”

Section: Ii)mentioning

confidence: 99%

“…to form a complex with H2O (HO2•H2O), which reacts 4-8 times faster with NO, creating HNO3, at 50% relative humidity (RH) compared to under dry conditions (Butkovskaya et al, 2007;Butkovskaya et al, 2009;Duncianu et al, 2020). This leads to the measured chain length decreasing by a factor of two when going from dry conditions to 40% RH and by a factor of three at 70% RH (Duncianu et al, 2020;Mihele and Hastie, 1998). Finally, the chain length is impacted by the gas reagents (NO and CO).…”

Section: Ii)mentioning

confidence: 99%

“…This is favoured by longer chain peroxy radicals, and at high NO concentrations. The formation yield of organic nitrates and nitrites differs from a few percent to up to ~23% depending on the nature of the R group present (Duncianu et al, 2020). It is therefore important to determine the optimal concentrations of reagent gas for each individual instrument as it could vary with what material has been used in the reactor.…”

Section: Ii)mentioning

confidence: 99%

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Fundamental Oxidation Processes in the Remote Marine Atmosphere Investigated Using the NO-NO₂-O₃ Photostationary State

Andersen

Nelson²,

Read³

et al. 2022

Preprint

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Abstract. The photostationary state (PSS) equilibrium between NO and NO2 is reached within minutes in the atmosphere and can be described by the PSS parameter, φ. Deviations from expected values of φ have previously been used to infer missing oxidants in diverse locations, from highly polluted regions to the extremely clean conditions observed in the remote marine boundary layer (MBL), and have been interpreted as missing understanding of fundamental photochemistry. Here, contrary to these previous observations, we observe good agreement between PSS-derived NO2 ([NO2]PSS ext.) calculated from photochemical model predictions of peroxy radicals (RO2 and HO2) and measured NO, O3, and jNO2, and observed NO2 in extremely clean air containing low levels of CO (< 90 ppbV) and VOCs. However, in clean air containing small amounts of aged pollution (CO > 100 ppbV), we observed higher levels of NO2 than inferred from the PSS, with [NO2]Obs./[NO2]PSS ext. of 1.12–1.68 (25th–75th percentile) implying 18.5–104 pptV (25th–75th percentile) of missing RO2 radicals. Potential NO2 measurement artefacts have to be carefully considered when comparing PSS-derived NO2 to observed NO2, but we show that the NO2 artefact required to explain the deviation would have to be ~ 4 times greater than the maximum calculated from known interferences. If the missing RO2 radicals have an ozone production efficiency equivalent to that of methyl peroxy radicals (CH3O2), then the calculated net ozone production including these additional oxidants is similar to that observed, within estimated uncertainties, once halogen oxide chemistry is accounted for. This implies that peroxy radicals cannot be excluded as the missing oxidant in clean marine air containing aged pollution, and that measured and modelled RO2 are both significantly underestimated under these conditions.

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Section: Ii)mentioning

confidence: 99%

Section: Ii)mentioning

confidence: 99%

Section: Ii)mentioning

confidence: 99%

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Fundamental Oxidation Processes in the Remote Marine Atmosphere Investigated Using the NO-NO₂-O₃ Photostationary State

Andersen

Nelson²,

Read³

et al. 2022

Preprint

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“…The detailed calculation of α is given in Butkovskaya et al (2009); Gottschaldt et al (2013). Following the results of Duncianu et al (2020), the 2-fold lower reaction rate k 2w is used here. The potential role of water complexes in the kinetics of organic peroxy radicals has been indicated in a few studies (Kumbhani et al, 2015;Clark et al, 2008Clark et al, , 2010.…”

Section: Modified Kinetics Of No Xmentioning

confidence: 99%

The influence of weather-driven processes on tropospheric ozone

Emmerichs¹,

Franco²,

Wespes³

et al. 2021

Preprint

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Abstract. Near-surface ozone is an harmful air pollutant, which is determined to a considerable extent by weather-controlled processes, and may be significantly impacted by water vapour forming complexes with peroxy radicals. The role of water in the reaction of HO2 radical with nitrogen oxides is known from the literature, and in current models the water complex is considered by assuming a linear dependence on water concentrations. In fact, recent experimental evidence has been published, showing the significant role of water on the kinetics of one of the most important reaction for ozone chemistry, namely NO2 + OH. Here, the available kinetic data for the HOx + NOx reactions have been included in the atmospheric chemistry model ECHAM5/MESSy (EMAC) to test its global significance. Among the modified kinetics, the newly added HNO3 channel from HO2 + NO, dominates, significantly reducing NO2. A major removal process of near-surface ozone is dry deposition accounting for 20 % of the total tropospheric ozone loss mostly occurring over vegetation. However, parameterizations for modelling dry deposition represent a major source of uncertainty for tropospheric ozone simulations. This potentially belongs to the reasons why global models, such as EMAC used here, overestimate ozone with respect to observations. In fact, the employed parameterization is hardly sensitive to local meteorological conditions (e.g., humidity) and lacks non-stomatal deposition. In this study, a dry deposition scheme including these features have been used in EMAC, affecting not only the deposition of ozone but of its precursors, resulting in lower chemical production of ozone. Additionally, we improved the emissions of isoprene and nitrous acid (HONO). Namely, for isoprene emissions we have accounted for the impact of drought stress which confers a higher model sensitivity to meteorology leading to reduced annual emissions down to 32 %. For HONO, we have implemented soil emissions, which depend on soil moisture and thus on precipitation. We estimate for the first time a global source strength of 7 Tg(N) a−1. Furthermore, the usage of a parameterization for the production of lightning NOx that depends on cloud top height contributes to a more realistic representation of NO2 columns over remote oceans with respect to the satellite measurements of the Ozone Monitoring Instrument (OMI). The combination of all the model modifications reduces the simulated global ozone burden by ≈ 20 % to 337 Tg, which is in better agreement with recent estimates. By comparing simulation results with measurements from the Infrared Atmospheric Sounding Interferometer (IASI) and the Tropospheric Ozone Assessment Report (TOAR) databases (of 2009) we demonstrate an overall reduction of the ozone bias by a factor of 2.

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“…As its name implies, this uses ethane (C 2 H 6 ) rather than CO for the amplification of atmospheric peroxy radicals (Wood et al, 2017). Although the amplification is lower than for CO, the chain length appears to be less sensitive to humidity effects (Duncianu et al, 2020). Chemical amplification using a CO and SO 2 chain conversion in combination with chemical ionisation mass spectrometry (CIMS) has been used for the measurement of RO * 2 (Reiner et al, 1997;Hanke et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

Airborne measurement of peroxy radicals using chemical amplification coupled with cavity ring-down spectroscopy: the PeRCEAS instrument

et al. 2020

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Abstract. Hydroperoxyl (HO2) and organic peroxy (RO2) radicals have an unpaired spin and are highly reactive free radicals. Measurements of the sum of HO2 and RO2 provide unique information about the chemical processing in an air mass. This paper describes the experimental features and capabilities of the Peroxy Radical Chemical Enhancement and Absorption Spectrometer (PeRCEAS). This is an instrument designed to make measurements on aircraft from the boundary layer to the lower stratosphere. PeRCEAS combines the amplified conversion of peroxy radicals to nitrogen dioxide (NO2) with the sensitive detection of NO2 using cavity ring-down spectroscopy (CRDS) at 408 nm. PeRCEAS is a dual-channel instrument, with two identical reactor–detector lines working out of phase with one another at a constant and defined pressure lower than ambient at the aircraft altitude. The suitability of PeRCEAS for airborne measurements in the free troposphere was evaluated by extensive characterisation and calibration under atmospherically representative conditions in the laboratory. The use of alternating modes of the two instrumental channels successfully captures short-term variations in the sum of peroxy radicals, defined as RO2∗ (RO2∗=HO2+∑RO2+OH+∑RO, with R being an organic chain) in ambient air. For a 60 s measurement, the RO2∗ detection limit is < 2 pptv for a minimum (2σ) NO2 detectable mixing ratio < 60 pptv, under laboratory conditions in the range of atmospheric pressures and temperatures expected in the free troposphere. PeRCEAS has been successfully deployed within the OMO (Oxidation Mechanism Observations) and EMeRGe (Effect of Megacities on the transport and transformation of pollutants on the Regional and Global scales) missions in different airborne campaigns aboard the High Altitude LOng range research aircraft (HALO) for the study of the composition of the free troposphere.

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Characterization of a chemical amplifier for peroxy radical measurements in the atmosphere

Cited by 11 publications

References 58 publications

Fundamental Oxidation Processes in the Remote Marine Atmosphere Investigated Using the NO-NO₂-O₃ Photostationary State

Fundamental Oxidation Processes in the Remote Marine Atmosphere Investigated Using the NO-NO₂-O₃ Photostationary State

The influence of weather-driven processes on tropospheric ozone

Airborne measurement of peroxy radicals using chemical amplification coupled with cavity ring-down spectroscopy: the PeRCEAS instrument

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Characterization of a chemical amplifier for peroxy radical measurements in the atmosphere

Cited by 11 publications

References 58 publications

Fundamental Oxidation Processes in the Remote Marine Atmosphere Investigated Using the NO-NO2-O3 Photostationary State

Fundamental Oxidation Processes in the Remote Marine Atmosphere Investigated Using the NO-NO2-O3 Photostationary State

The influence of weather-driven processes on tropospheric ozone

Airborne measurement of peroxy radicals using chemical amplification coupled with cavity ring-down spectroscopy: the PeRCEAS instrument

Contact Info

Product

Resources

About

Fundamental Oxidation Processes in the Remote Marine Atmosphere Investigated Using the NO-NO₂-O₃ Photostationary State

Fundamental Oxidation Processes in the Remote Marine Atmosphere Investigated Using the NO-NO₂-O₃ Photostationary State