Critical Role of Iodous Acid in Neutral Iodine Oxoacid Nucleation

Zhang, Rongjie; Xie, Hong-Bin; Ma, Fangfang; Chen, Jingwen; Iyer, Siddharth; Simon, Mario; Heinritzi, Martin; Shen, Jiali; Tham, Yee Jun; Kurtén, Theo; Worsnop, Douglas R.; Kirkby, J.; Curtius, Joachim; Sipilä, Mikko; Kulmala, Markku; He, Xu‐Cheng

doi:10.1021/acs.est.2c04328

Cited by 28 publications

(66 citation statements)

References 66 publications

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“…Iodine nucleation was conventionally thought to be initiated by iodine oxides (Jimenez, 2003;Gomez Martin et al, 2020;O'dowd and Hoffmann, 2005;Hoffmann et al, 2001;O'dowd et al, 2002). However, field observations at the Mace Head observatory and dedicated experiments carried out in the CLOUD chamber at CERN revealed iodine oxoacids (HIOx,i.e.,HIO3 and HIO2 in this study) as the key nucleating species in pristine regions (Zhang et al, 2022;He et al, 2021b). With state-80 of-the-art mass spectrometric methods, iodine oxoacids were recently identified in locations other than mid-latitude costal sites, such as in Arctic sites (Sipilä et al, 2016;Baccarini et al, 2020;Beck et al, 2021;He et al, 2021b), Antarctica sites (Jokinen et al, 2018;He et al, 2021b), boreal forest sites (Jokinen et al, 2022;He et al, 2021b), a remote marine site (He et al, 2021b) and importantly also in polluted urban sites (He et al, 2021b).…”

Section: Introductionmentioning

confidence: 49%

Iodine oxoacids and their roles in sub-3 nanometer particle growth in polluted urban environments

Zhang

et al. 2023

Preprint

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Abstract. New particle formation processes contribute significantly to the number concentration of ultrafine particles (UFP), and have great impacts on human health and global climate. Iodine oxoacids (HIOx, including iodic acid, HIO3 and iodous acid, HIO2) have been observed in pristine regions and proved to dominate NPF events at some sites. However, the knowledge of HIOx in polluted urban areas is rather limited. Here, we conducted a long-term comprehensive observation of gaseous iodine oxoacids and sulfuric acid in Beijing from January 2019 to October 2021 and also in Nanjing from March 2019 to February 2020, and investigated the contribution of HIOx to UFP number concentration in urban environments. HIO3 concentration is highest in summer, up to 2.85×106 cm-3 and 2.78×106 cm-3 in Beijing and Nanjing, respectively, and is lowest in winter, with a more prominent seasonal variation than H2SO4. HIO3 concentration shows a clear diurnal pattern at both sites with a daily maximum at around noontime, similar to the atmospheric temperature, radiation and ozone (O3) levels. HIO2 concentration has the same diurnal and seasonal trend as HIO3 but is overall about one order of magnitude lower than HIO3 concentration. Back trajectory analysis suggests that the sources for inland iodine species could be a mix of marine and terrestrial origins, both having peak iodine emission in warm seasons. While the contribution of HIO2 to particle growth is marginal in Beijing and Nanjing, our results demonstrate that HIO3 enhances the particle survival probability of sub-3 nm particles by about 40 % (median) and occasionally by more than 100 % in NPF events, suggesting HIOx are non-negligible contributor to UFPs in polluted urban areas. As the growth contribution from HIO3 and H2SO4 is similar on a per-molecule basis, we propose that the sum of HIO3 and H2SO4 could be used to estimate sub-3 nm particle growth of inorganic acid origin, in the polluted atmospheres with a significant amount of HIOx.

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Section: Introductionmentioning

confidence: 49%

Iodine oxoacids and their roles in sub-3 nanometer particle growth in polluted urban environments

Zhang

et al. 2023

Preprint

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“…Oxidised iodine vapours have been shown to influence atmospheric oxidation capacity (Sherwen et al, 2016;Wang et al, 2021b) and particle formation processes (Hoffmann et al, 2001;O'Dowd et al, 2002). Recent publications have suggested iodine oxoacids as the critical driver for iodine particle formation processes (Sipilä et al, 2016;Baccarini et al, 2020;He et al, 2021b, a;Zhang et al, 2022;Liu et al, 2023). However, active debate remains concerning the presence of gaseous HIO 3 and whether HIO 3 plays an important role in atmospheric aerosol nucleation.…”

Section: Validation Of the Measurement Of Iodine-containing Speciesmentioning

confidence: 99%

Characterisation of the multi-scheme chemical ionisation inlet-2 and the detection of gaseous iodine species

Shen

Iyer

et al. 2023

Preprint

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Abstract. The multi-scheme chemical ionisation inlet 1 (MION1) allows fast switching between measuring atmospheric ions without chemical ionisation and neutral molecules by multiple chemical ionisation methods. In this study, the upgraded multi-scheme chemical ionisation inlet 2 (MION2) is presented. The new design features improved ion optics that increase the reagent ion concentration, a generally more robust operation and the possibility to run multiple chemical ionisation methods with the same ionisation time. To simplify the regular calibration of MION2, we developed an open-source flow reactor chemistry model (MARFORCE) to quantify the chemical production of sulfuric acid (H2SO4), hypoiodous acid (HOI) and hydroperoxyl radical (HO2). MARFORCE simulates convection-diffusion-reaction processes inside typical cylindrical flow reactors with uniform inner diameters. The model also provides options to simulate the chemical processes 1) when two flow reactors with different inner diameters are connected together and 2) when two flows are merged into one (connected by a Y-shape tee), but with reduced accuracy. Additionally, the chemical mechanism files in the model are compatible with the widely-used Master Chemical Mechanism, thus allowing future adaptation to simulate other chemical processes in flow reactors. We further carried out detailed characterisation of the bromide (Br−) and nitrate (NO3−) chemical ionisation methods with different ionisation times. We calibrated H2SO4, HOI and HO2 by combining gas kinetic experiments with the MARFORCE model. Sulfur dioxide (SO2), water (H2O) and molecular iodine (I2) were evaluated using dilution experiments from a gas cylinder (SO2), dew point mirror measurements (H2O), and a derivatization approach in combination with high-performance liquid chromatography quantification (I2), respectively. We find that the detection limit is negatively correlated with the fragmentation enthalpy of the analyte-reagent ion (Br−) cluster, i.e., a stronger binding (larger fragmentation enthalpy) leads to a lower detection limit. Additionally, a moderately longer reaction time enhances the detection sensitivity thus decreasing the detection limit. For example, the detection limit for H2SO4 is estimated to be 2.9 × 104 molec. cm−3 with a 300 ms ionisation time. A direct comparison suggests that this is even better than the widely-used Eisele-type chemical ionisation inlet. While the NO3− chemical ionisation method is generally more robust, we find that the Br− chemical ionisation method (Br−-MION2) is significantly affected by air water content. Higher air water content results in lower sensitivity for HO2 and SO2 within the examined conditions. On the other hand, a steep sensitivity drop of H2SO4, HOI and I2 is only observed when the dew point is greater than 0.5–10.5 ℃ (equivalent to 20–40 % RH; calculated at 25 ℃ hereafter). Future studies utilising atmospheric pressure Br− chemical ionisation method, including Br−-MION2, should carefully address the humidity effect on a molecular basis. By combining methods such as water-insensitive NO3−-MION2 with Br−-MION2, MION2 should be able to provide greater details of air composition than either of these methods alone. Combining instrument voltage-scanning, chemical kinetic experiments and quantum chemical calculations, we find that the HIO3 detection is not interfered with by iodine oxides under atmospherically relevant conditions. The IO3−, HIO3NO3− and HIO3Br− ions measured using the Br− and NO3− chemical ionisation methods are primarily, if not exclusively, produced from gaseous HIO3 molecules.

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“…18−22 Among the investigated compounds, HIO 2 was found to have the highest enhancement to pure IA nucleation. 18 However, the current knowledge may not well predict IA-induced nucleation under all circumstances, especially in chemically complex polluted and semi-polluted environments. As the presence of iodine species in polluted environments has been unambiguously revealed, 14,23 it is necessary to investigate the enhancing potential of other compounds on IA-induced nucleation, with special attention to compounds with stronger enhancing potential compared to HIO 2 .…”

Section: ■ Introductionmentioning

confidence: 99%

“…The distribution of stable clusters of the IA-DEA system is similar to the case of the IA-DMA system 21 and different from most of the SA-amine systems [27][28][29]57 and the IA-HIO 2 system. 18 Cluster Growth Pathway. Figure 5 shows the cluster growth pathways of the IA-DEA clusters at 278.15 K with [IA] = 10 7 cm −3 , [DEA] = 2.5 × 10 7 cm −3 , and k coag = 2.0 × 10 −3 s −1 .…”

Section: ■ Introductionmentioning

confidence: 99%

“…could interact with IA and enhance the IA-induced aerosol nucleation in the marine atmosphere. However, the enhancement from only a limited subset of these compounds, i.e., iodous acid (HIO 2 ), NH 3 , DMA, SA, and MSA, has been investigated using quantum chemical calculations. − Among the investigated compounds, HIO 2 was found to have the highest enhancement to pure IA nucleation . However, the current knowledge may not well predict IA-induced nucleation under all circumstances, especially in chemically complex polluted and semi-polluted environments.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Enhancement of Atmospheric Nucleation Precursors on Iodic Acid-Induced Nucleation: Predictive Model and Mechanism

Xie

Zhang

et al. 2023

Environ. Sci. Technol.

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Iodic acid (IA) has recently been recognized as a key driver for new particle formation (NPF) in marine atmospheres. However, the knowledge of which atmospheric vapors can enhance IA-induced NPF remains limited. The unique halogen bond (XB)-forming capacity of IA makes it difficult to evaluate the enhancing potential (EP) of target compounds on IA-induced NPF based on widely studied sulfuric acid systems. Herein, we employed a three-step procedure to evaluate the EP of potential atmospheric nucleation precursors on IA-induced NPF. First, we evaluated the EP of 63 precursors by simulating the formation free energies (ΔG) of the IA-containing dimer clusters. Among all dimer clusters, 44 contained XBs, demonstrating that XBs are frequently formed. Based on the calculated ΔG values, a quantitative structure–activity relationship model was developed for evaluating the EP of other precursors. Second, amines and O/S-atom-containing acids were found to have high EP, with diethylamine (DEA) yielding the highest potential to enhance IA-induced nucleation by combining both the calculated ΔG and atmospheric concentration of considered 63 precursors. Finally, by studying larger (IA)1–3(DEA)1–3 clusters, we found that the IA-DEA system with merely 0.1 ppt (2.5×106 cm–3) DEA yields comparable nucleation rates to that of the IA–iodous acid system.

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Critical Role of Iodous Acid in Neutral Iodine Oxoacid Nucleation

Cited by 28 publications

References 66 publications

Iodine oxoacids and their roles in sub-3 nanometer particle growth in polluted urban environments

Iodine oxoacids and their roles in sub-3 nanometer particle growth in polluted urban environments

Characterisation of the multi-scheme chemical ionisation inlet-2 and the detection of gaseous iodine species

Enhancement of Atmospheric Nucleation Precursors on Iodic Acid-Induced Nucleation: Predictive Model and Mechanism

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