Natural short-lived halogens exert an indirect cooling effect on climate.

Observational evidence shows the ubiquitous presence of ocean-emitted short-lived halogens in the global atmosphere1-3. Natural emissions of these chemical compounds have been anthropogenically amplified since pre-industrial times4-6, while, in addition, anthropogenic short-lived halocarbons are currently being emitted to the atmosphere7,8. Despite their widespread distribution in the atmosphere, the combined impact of these species on Earth's radiative balance remains unknown. Here we show that short-lived halogens exert a substantial indirect cooling effect at present (-0.13 ± 0.03 watts per square metre) that arises from halogen-mediated radiative perturbations of ozone (-0.24 ± 0.02 watts per square metre), compensated by those from methane (+0.09 ± 0.01 watts per square metre), aerosols (+0.03 ± 0.01 watts per square metre) and stratospheric water vapour (+0.011 ± 0.001 watts per square metre). Importantly, this substantial cooling effect has increased since 1750 by -0.05 ± 0.03 watts per square metre (61 per cent), driven by the anthropogenic amplification of natural halogen emissions, and is projected to change further (18-31 per cent by 2100) depending on climate warming projections and socioeconomic development. We conclude that the indirect radiative effect due to short-lived halogens should now be incorporated into climate models to provide a more realistic natural baseline of Earth's climate system.

Polarimetric imaging for the detection of synthetic models of SARS-CoV-2: A proof of concept.

Objective: To conduct a proof-of-concept study of the detection of two synthetic models of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) using polarimetric imaging. Approach: Two SARS-CoV-2 models were prepared as engineered lentiviruses pseudotyped with the G protein of the vesicular stomatitis virus, and with the characteristic Spike protein of SARS-CoV-2. Samples were prepared in two biofluids (saline solution and artificial saliva), in four concentrations, and deposited as 5-µL droplets on a supporting plate. The angles of maximal degree of linear polarization (DLP) of light diffusely scattered from dry residues were determined using Mueller polarimetry from87 samples at 405 nm and 514 nm. A polarimetric camera was used for imaging several samples under 380-420 nm illumination at angles similar to those of maximal DLP. Per-pixel image analysis included quantification and combination of polarization feature descriptors in 475 samples. Main results: The angles (from sample surface) of maximal DLP were 3° for 405 nm and 6° for 514 nm. Similar viral particles that differed only in the characteristic spike protein of the SARS-CoV-2, their corresponding negative controls, fluids, and the sample holder were discerned at 10-degree and 15-degree configurations. Significance: Polarimetric imaging in the visible spectrum may help improve fast, non-contact detection and identification of viral particles, and/or other microbes such as tuberculosis, in multiple dry fluid samples simultaneously, particularly when combined with other imaging modalities. Further analysis including realistic concentrations of real SARS-CoV-2 viral particles in relevant human fluids is required. Polarimetric imaging under visible light may contribute to a fast, cost-effective screening of SARS-CoV-2 and other pathogens when combined with other imaging modalities.

Insights into the Chemistry of Iodine New Particle Formation: The Role of Iodine Oxides and the Source of Iodic Acid.

Iodine chemistry is an important driver of new particle formation in the marine and polar boundary layers. There are, however, conflicting views about how iodine gas-to-particle conversion proceeds. Laboratory studies indicate that the photooxidation of iodine produces iodine oxides (IxOy), which are well-known particle precursors. By contrast, nitrate anion chemical ionization mass spectrometry (CIMS) observations in field and environmental chamber studies have been interpreted as evidence of a dominant role of iodic acid (HIO3) in iodine-driven particle formation. Here, we report flow tube laboratory experiments that solve these discrepancies by showing that both IxOy and HIO3 are involved in atmospheric new particle formation. I2Oy molecules (y = 2, 3, and 4) react with nitrate core ions to generate mass spectra similar to those obtained by CIMS, including the iodate anion. Iodine pentoxide (I2O5) produced by photolysis of higher-order IxOy is hydrolyzed, likely by the water dimer, to yield HIO3, which also contributes to the iodate anion signal. We estimate that ∼50% of the iodate anion signals observed by nitrate CIMS under atmospheric water vapor concentrations originate from I2Oy. Under such conditions, iodine-containing clusters and particles are formed by aggregation of I2Oy and HIO3, while under dry laboratory conditions, particle formation is driven exclusively by I2Oy. An updated mechanism for iodine gas-to-particle conversion is provided. Furthermore, we propose that a key iodine reservoir species such as iodine nitrate, which we observe as a product of the reaction between iodine oxides and the nitrate anion, can also be detected by CIMS in the atmosphere.

Reaction of SO3 with HONO2 and Implications for Sulfur Partitioning in the Atmosphere.

Sulfur trioxide is a critical intermediate for the sulfur cycle and the formation of sulfuric acid in the atmosphere. The traditional view is that sulfur trioxide is removed by water vapor in the troposphere. However, the concentration of water vapor decreases significantly with increasing altitude, leading to longer atmospheric lifetimes of sulfur trioxide. Here, we utilize a dual-level strategy that combines transition state theory calculated at the W2X//DF-CCSD(T)-F12b/jun'-cc-pVDZ level, with variational transition state theory with small-curvature tunneling from direct dynamics calculations at the M08-HX/MG3S level. We also report the pressure-dependent rate constants calculated using the system-specific quantum Rice-Ramsperger-Kassel (SS-QRRK) theory. The present findings show that falloff effects in the SO3 + HONO2 reaction are pronounced below 1 bar. The SO3 + HONO2 reaction can be a potential removal reaction for SO3 in the stratosphere and for HONO2 in the troposphere, because the reaction can potentially compete well with the SO3 + 2H2O reaction between 25 and 35 km, as well as the OH + HONO2 reaction. The present findings also suggest an unexpected new product from the SO3 + HONO2 reaction, which, although very short-lived, would have broad implications for understanding the partitioning of sulfur in the stratosphere and the potential for the SO3 reaction with organic acids to generate organosulfates without the need for heterogeneous chemistry.

The Chemistry of Mercury in the Stratosphere.

Mercury, a global contaminant, enters the stratosphere through convective uplift, but its chemical cycling in the stratosphere is unknown. We report the first model of stratospheric mercury chemistry based on a novel photosensitized oxidation mechanism. We find two very distinct Hg chemical regimes in the stratosphere: in the upper stratosphere, above the ozone maximum concentration, Hg0 oxidation is initiated by photosensitized reactions, followed by second-step chlorine chemistry. In the lower stratosphere, ground-state Hg0 is oxidized by thermal reactions at much slower rates. This dichotomy arises due to the coincidence of the mercury absorption at 253.7 nm with the ozone Hartley band maximum at 254 nm. We also find that stratospheric Hg oxidation, controlled by chlorine and hydroxyl radicals, is much faster than previously assumed, but moderated by efficient photo-reduction of mercury compounds. Mercury lifetime shows a steep increase from hours in the upper-middle stratosphere to years in the lower stratosphere.

The reaction between HgBr and O3: kinetic study and atmospheric implications.

The rate constants of many reactions currently considered to be important in the atmospheric chemistry of mercury remain to be measured in the laboratory. Here we report the first experimental determination of the rate constant of the gas-phase reaction between the HgBr radical and ozone, for which a value at room temperature of k(HgBr + O3) = (7.5 ± 0.6) × 10-11 cm3 molecule s-1 (1σ) has been obtained. The rate constants of two reduction side reactions were concurrently determined: k(HgBr + O) = (5.3 ± 0.4) × 10-11 cm3 molecule s-1 and k(HgBrO + O) = (9.1 ± 0.6) × 10-11 cm3 molecule s-1. The value of k(HgBr + O3) is slightly lower than the collision number, confirming the absence of a significant energy barrier. Considering the abundance of ozone in the troposphere, our experimental rate constant supports recent modelling results suggesting that the main atmospheric fate of HgBr is reaction with ozone to form BrHgO.

Comparing infant and toddler sleep patterns prior to and during the first wave of home confinement due to COVID-19 in Spain.

Recent literature has shown that sleep patterns are shaped during the first years of life, playing a relevant role in children's functioning. We focused on comparing sleep patterns in infants and toddlers in Spain before and during COVID-19 home confinement to assess the immediate impact on sleep patterns. We compared data from two cross-sectional surveys from parents of 1658 children three to 36 months of age from Spain. One conducted before COVID-19 (2017-2018, n = 1380) and another during COVID-19 pandemic (March-May of 2020, n = 254). We used an internet self-administrated questionnaire using the Brief Infant Sleep Questionnaire (BISQ) criteria in both surveys. During confinement, infants and toddlers went to sleep later (median bedtime 21:30 before confinement vs. 21:36 during confinement (p = 0.004)). More infants and toddlers showed longer sleep latencies (> 30 min) during confinement median 33.9% versus 12.3% (p < 0.001). Based on the recommended BISQ criteria, we observed an increase in poor sleepers meeting at least one criterion of inadequate patterns during confinement (p < 0.001). Parental perception of a child's sleep as problematics were 39.4% and 44.1% (adjusted p = 0.363) before and under lockdown, respectively. CONCLUSION: Home confinement generally affected infant's and toddler's sleep patterns negatively; however, parents did not report worse perception of sleep quality of their children. Follow-up studies can help understand the potential long-term effects of the COVID-19 pandemic on sleep patterns. WHAT IS KNOWN: • Adequate sleep patterns in infants and toddlers are relevant as they are linked to proper and long-term social-emotional development as well as adequate daytime functioning. • Regarding sleep patterns in paediatrics during the COVID pandemic, recent literature has described an increase in total daily sleep time as well as more exposure to screens in children and adolescents, providing evidence of immediate collateral consequences of the COVID-19 outbreak. WHAT IS NEW: • Comparing sleep patterns in two samples of infants and toddlers in Spain before and during COVID-confinement, we found later bedtimes as well as a significant increase in infants' and toddlers' sleep latency by >30 min during confinement. • Parental self-reported questionnaire during COVID-19 home confinement reported an overall worsening of their children's sleep based on the BISQ criteria.

Gal3 Plays a Deleterious Role in a Mouse Model of Endotoxemia.

Lipopolysaccharide (LPS)-induced endotoxemia induces an acute systemic inflammatory response that mimics some important features of sepsis, the disease with the highest mortality rate worldwide. In this work, we have analyzed a murine model of endotoxemia based on a single intraperitoneal injection of 5 mg/kg of LPS. We took advantage of galectin-3 (Gal3) knockout mice and found that the absence of Gal3 decreased the mortality rate oflethal endotoxemia in the first 80 h after the administration of LPS, along with a reduction in the tissular damage in several organs measured by electron microscopy. Using flow cytometry, we demonstrated that, in control conditions, peripheral immune cells, especially monocytes, exhibited high levels of Gal3, which were early depleted in response to LPS injection, thus suggesting Gal3 release under endotoxemia conditions. However, serum levels of Gal3 early decreased in response to LPS challenge (1 h), an indication that Gal3 may be extravasated to peripheral organs. Indeed, analysis of Gal3 in peripheral organs revealed a robust up-regulation of Gal3 36 h after LPS injection. Taken together, these results demonstrate the important role that Gal3 could play in the development of systemic inflammation, a well-established feature of sepsis, thus opening new and promising therapeutic options for these harmful conditions.

Analysis of the main determinants of away-from-home consumption of fishery and aquaculture products in the EU28.

The European Union (EU) is the largest market in nominal terms for fishery and aquaculture products (FAPs), partly due to the away-from-home consumption of these products in restaurants and food outlets. In view of this, it is necessary to identify the main determinants of the away-from-home consumption patterns in order to propose strategies that could increase the consumption of FAPs. Following this, ordered probit models were estimated alongside their marginal effects to identify the most relevant factors determining the frequency of away-from-home consumption of FAPs in the EU28, using a representative sample of 27732 EU residents. We found that those in the highest classes of society are most likely to consume FAPs away-from-home more frequently. Also, the most important reasons for consuming FAPs away-from-home more frequently are that they are less expensive than other foods, taste good, and are healthy and easy to digest. In addition, among the different nationalities, British consumers are more likely to consume FAPs away-from-home. We also found that there is a higher frequency of away-from-home consumption of FAPs for consumers between the ages of 25 and 54, who do not live in rural areas, who prefer wild-caught and local and marine products, and that are very satisfied with their lives. The study contributes to the literature with the analysis of FAPs away-from-home consumption by using a large representative sample of EU28 consumers. The study is also relevant with respect to the extensive list of determinants that include factors related to the attitudes of respondents to FAPs and socio-demographic characteristics.

HIOx-IONO2 Dynamics at the Air-Water Interface: Revealing the Existence of a Halogen Bond at the Atmospheric Aerosol Surface.

Iodine is enriched in marine aerosols, particularly in coastal mid-latitude atmospheric environments, where it initiates the formation of new aerosol particles with iodic acid (HIO3) composition. However, particle formation in polluted and semipolluted locations is inhibited when the iodine monoxide radical (IO) is intercepted by NO2 to form the iodine nitrate (IONO2). The primary fate of IONO2 is believed to be, besides photolysis, uptake by aerosol surfaces, leading to particulate iodine activation. Herein we have performed Born-Oppenheimer molecular dynamics (BOMD) simulations and gas-phase quantum chemical calculations to study the iodine acids-iodine nitrate [HIOx (x = 2 and 3)-IONO2] dynamics at the air-water interface modeled by a water droplet of 191 water molecules. The results indicate that IONO2 does not react directly with these iodine acids, but forms an unusual kind of interaction with them within a few picoseconds, which is characterized as halogen bonding. The halogen bond-driven HIO3-IONO2 complex at the air-water interface undergoes deprotonation and exists as IO3--IONO2 anion, whereas the HIO2-IONO2 complex does not exhibit any proton loss to the interfacial water molecules. The gas-phase quantum chemical calculations suggest that the HIO3-IONO2 and HIO2-IONO2 complexes have appreciable stabilization energies, which are significantly enhanced upon deprotonation of iodine acids, indicating that these halogen bonds are fairly stable. These IONO2-induced halogen bonds explain the rapid loss of IONO2 to background aerosol. Moreover, they appear to work against iodide formation. Thus, they may play an important role in enhancing the amount of atmospherically nonrecyclable iodine (iodate) in marine aerosol.

A study of the dissociative recombination of CaO+ with electrons: Implications for Ca chemistry in the upper atmosphere.

The dissociative recombination of CaO+ ions with electrons has been studied in a flowing afterglow reactor. CaO+ was generated by the pulsed laser ablation of a Ca target, followed by entrainment in an Ar+ ion/electron plasma. A kinetic model describing the gas-phase chemistry and diffusion to the reactor walls was fitted to the experimental data, yielding a rate coefficient of (3.0 ± 1.0) × 10-7 cm3 molecule-1 s-1 at 295 K. This result has two atmospheric implications. First, the surprising observation that the Ca+/Fe+ ratio is ~8 times larger than Ca/Fe between 90 and 100 km in the atmosphere can now be explained quantitatively by the known ion-molecule chemistry of these two metals. Second, the rate of neutralization of Ca+ ions in a descending sporadic E layer is fast enough to explain the often explosive growth of sporadic neutral Ca layers.

Under what conditions does (SiO)N nucleation occur? A bottom-up kinetic modelling evaluation.

Silicon monoxide (SiO) is a structurally complex compound exhibiting differentiated oxide-rich and silicon-rich nano-phases at length scales covering nanoclusters to the bulk. Although nano-sized and nano-segregated SiO has great technological potential (e.g. nano-silicon for optical applications) and is of enormous astronomical interest (e.g. formation of silicate cosmic dust) an accurate general description of SiO nucleation is lacking. Avoiding the deficiencies of a bulk-averaged approach typified by classical nucleation theory (CNT) we employ a bottom-up kinetic model which fully takes into account the atomistic details involved in segregation. Specifically, we derive a new low energy benchmark set of segregated (SiO)N cluster ground state candidates for N ≤ 20 and use the accurately calculated properties of these isomers to calculate SiO nucleation rates. We thus provide a state-of-the art evaluation of the range of pressure and temperature conditions for which formation of SiO will or will not proceed. Our results, which match with available experiment, reveal significant deficiencies with CNT approaches. We employ our model to shed light on controversial issue of circumstellar silicate dust formation showing that, at variance with the predictions from CNT-based calculations, pure SiO nucleation under such conditions is not viable.

Mesospheric removal of very long-lived greenhouse gases SF6 and CFC-115 by metal reactions, Lyman-α photolysis, and electron attachment.

The fluorinated gases SF6 and C2F5Cl (CFC-115) are chemically inert with atmospheric lifetimes of many centuries which, combined with their strong absorption of IR radiation, results in unusually high global warming potentials. Very long lifetimes imply that mesospheric sinks could make important contributions to their atmospheric removal. In order to investigate this, the photolysis cross sections at the prominent solar Lyman-α emission line (121.6 nm), and the reaction kinetics of SF6 and CFC-115 with the neutral meteoric metal atoms Na, K, Mg, and Fe over large temperature ranges, were measured experimentally. The Na and K reactions exhibit significant non-Arrhenius behavior; quantum chemistry calculations of the potential energy surfaces for the SF6 reactions indicate that the Na and K reactions with SF6 are probably activated by vibrational excitation of the F-SF5 (v3) stretching mode. A limited set of kinetic measurements on Na + SF5CF3 are also presented. The atmospheric removal of these long-lived gases by a variety of processes is then evaluated. For SF6, the removal processes in decreasing order of importance are electron attachment, VUV photolysis, and reaction with K, Na, and H. For CFC-115, the removal processes in decreasing order of importance are reaction with O((1)D), VUV photolysis, and reaction with Na, K, and H.

Professionals' digital competences and user profiles in social agencies and their impact on professional practice, family autonomy and wellbeing.

Introduction: The health crisis of the last 3 years has revealed the weaknesses of the child and family support system based on the professional use of digital resources in social agencies. This study addresses three aims: to examine the level of professional digital competence; to analyze the user profiles in a variety of digital resources; and to test the impact of level of competences and user profiles on four aspects: professional practice, family satisfaction with the services, child and family wellbeing, and family autonomy in the exercise of the parenting role. Methods: Participants were 148 practitioners from social agencies who voluntarily responded to an online survey with 47 questions. Results and discussion: Results showed that professionals perceive themselves as more competent in areas of information / data management and communication / collaboration than in the creation of digital content, security measures, and technical problem solving. Websites, email, and instant messaging were the sources more frequently used and with higher satisfaction, than structured programs, social networks and multimedia content. Variability in the user profiles showed three clusters: Cluster 1 Social network user (n = 13), Cluster 2 Diversified user (n = 75) and Cluster 3 Communicative instant user (n = 60). Participants in Cluster 2 compared to those in the other clusters were the most proficient on their digital competences and acknowledge the positive impact of digital resources on their professional practice and the psychological and social wellbeing of families. This study points the need for improvement in professionals' digital competences in some of the measured areas and the user profile of digital resources since both provide benefits on professional practice and family autonomy and wellbeing.

The unstudied effects of wording and answer formats in the analysis of impartiality in public service provision.

Impartiality in public services provision is an important dimension that explains the quality of government (QoG). The analysis of impartiality has boomed in recent years at different territorial levels, like countries or regions. The impartiality measures depend on several attributes that are aggregated using different methods. However, little attention has been given to the effects of negative wording attributes and the number of format answers, despite the efforts made by previous studies to build robust composite impartiality indices. This study corrects this existing gap partly using one of the most extensive surveys (the European Quality of Government Index 2021) that include attributes related to impartiality (six attributes and 129,991 citizens). The method will be based on a fuzzy clustering approach, the extended Apostle model and an ordinary binary probit model. The results show that the type of wording and the number of answer options affect impartiality. The analysis of the main differences observed is affected by some insightful covariates such as country, gender, being native, town size, occupation, and the perception of the economic situation.

A comparison of attitudes towards immigrants from the perspective of the political party vote.

Many reasons have shaped immigration into the EU over the past decade. Since then, attitudes towards immigration have not only gained public attention but have also shaped political debate and discourse in recent regional, national, and EU elections. The global financial crisis of 2008 increased the importance of migration in the social welfare upheaval in most Member States. Anti-immigrant sentiment and rhetoric became part of the narrative of some political parties during the campaign, and media coverage catalysed these social attitudes. The study used the 2013 International Social Survey Project (ISSP) dataset of six countries (namely Belgium, Germany, Spain, France, the UK, and Portugal) to see if the political party vote might have affected the attitude toward immigrants. The study extends other previous studies and presents new evidence on an under-researched topic. Results show that the left party voters are more open toward immigrants than the right party voters and that the green party voters show the most positive attitudes towards immigrants.

Spectroscopy of a mesospheric ghost reveals iron emissions.

Mesospheric Green emissions from excited Oxygen in Sprite Tops (ghosts) are infrequent and faint greenish transient luminous events that remain for hundreds of milliseconds on top of certain energetic sprites. The main hypothesis to explain this glow persistence is the long lifetime of excited atomic oxygen at 557.73 nm, a well-known emission line in aurora and airglow. However, due to the lack of spectroscopic campaigns to analyse such events to date, the species involved in the process can not yet be identified. Here we report observational results showing the temporal evolution of a ghost spectrum between 500 nm and 600 nm. Besides weak -but certain- traces of excited atomic oxygen, our results show four main contributors related to the slow decay of the glow: atomic iron and nickel, molecular nitrogen and ionic molecular oxygen. Additionally, we are able to identify traces of atomic sodium, and ionic silicon, these observations being consistent with previous direct measurements of density profiles of meteoric metals in the mesosphere and lower thermosphere. This finding calls for an upgrade of current air plasma kinetic understanding under the influence of transient luminous events.

Lessons from the Criticality of the Spanish High Capacity Road Network on Direct, Representative Democracies and Technocracies.

This paper aims to shed some light on an issue that has not been analyzed enough in previous studies on complex transportation networks. The financial crisis and disrupting events like the COVID-19 pandemic episode are affecting how governments make crucial decisions regarding policymaking paying more attention to experts' opinions. The impacts of disruptive events that could affect each road section will be analyzed using the criticality of the high capacity road network in Spain under different policymaking scenarios, such as direct democracy based on pure provincial decentralization (federal or cantonal vision), representative democracy in which decisions are taken by the National Parliament, and the governance based on technocracy stimulated by 'what matters is what works' (Southern Local Economy, 16(4), 264-271, 2001) using an Evidence-Based Policy Making (EBPM) case study based on a Data Envelopment Analysis applied to four accessibility indicators. We will complement our analysis with the different results obtained by the different national parties that were represented in the past election (November, 2019): PSOE, PP, VOX, Unidas Podemos, Ezquerra Republicana de Catalunya, Ciudadanos, Junts per Catalunya, Partido Nacionalista Vasco and Euskal Herria Bildu, exploring in-depth the obtained differences between the technocrat solution and the direct and representative democracy results. Important insights and lessons for the future will be obtained from the different party visions observed among the regionalist (nationalist) and the state-wide parties. The spillover effects created by the networks are so important that the room for federalist solutions might be very limited. Supplementary Information: The online version contains supplementary material available at 10.1007/s12061-022-09451-5.

How to detect hospitals where quality would not be jeopardized by health cost savings? A methodological approach using DEA with SBM analysis.

BACKGROUND: In Spain the health care cuts have been the norm after the international economic crisis. The aim of this study is fourfold: (1) to measure hospital performance analysing two different perspectives: technical efficiency and quality; (2) to determine how technically efficient hospitals operate when faced with undesirable production; (3) to determine whether a potential trade-off between efficiency and quality exists or not; and (4) to propose a methodology to detect which hospitals could reduce their running costs without jeopardizing the quality of the services provided. Budget cutbacks imposed in Spain should focus solely on these hospitals, unless an increase in undesirable production is considered acceptable. METHODS: In this paper a SBM (slacks-based measure) of efficiency model is employed incorporating undesirable outputs using the case-mix adjusted deaths of patients. The study is carried out using information from 232 general hospitals in Spain. FINDINGS: We find four different groups of hospitals based on the relationship between efficiency and undesirable outputs. CONCLUSION: We show that undesirable outputs affect the measurement of technical efficiency, proposing a tool that allows the identification of hospitals where efficiency can be increased, that is, where budget cuts and/or more production outputs can be implemented without necessarily increasing the undesirable output.

On the Speciation of Iodine in Marine Aerosol.

We have compiled and analyzed a comprehensive data set of field observations of iodine speciation in marine aerosol. The soluble iodine content of fine aerosol (PM1) is dominated by soluble organic iodine (SOI; ∼50%) and iodide (∼30%), while the coarse fraction is dominated by iodate (∼50%), with nonnegligible amounts of iodide (∼20%). The SOI fraction shows an equatorial maximum and minima coinciding with the ocean "deserts," which suggests a link between soluble iodine speciation in aerosol and ocean productivity. Among the major aerosol ions, organic anions and non-sea-salt sulfate show positive correlations with SOI in PM1. Alkali cations are positively correlated to iodate and negatively correlated with SOI and iodide in coarse aerosol. These relationships suggest that under acidic conditions iodate is reduced to HOI, which reacts with organic matter to form SOI, a possible source of iodide. In less acidic sea-salt or dust-rich coarse aerosols, HOI oxidation to iodate and reaction with organic matter likely compete.