Faraday Discussions最新文献

{"title":"The impact of the Himalayan aerosol factory: results from high resolution numerical modelling of pure biogenic nucleation over the Himalayan valleys.","authors":"Giancarlo Ciarelli, Arineh Cholakian, Manuel Bettineschi, Bruno Vitali, Bertrand Bessagnet, Victoria A Sinclair, Johannes Mikkola, Imad El Haddad, Dino Zardi, Angela Marinoni, Alessandro Bigi, Paolo Tuccella, Jaana Bäck, Hamish Gordon, Tuomo Nieminen, Markku Kulmala, Douglas Worsnop, Federico Bianchi","doi":"10.1039/d4fd00171k","DOIUrl":"10.1039/d4fd00171k","url":null,"abstract":"<p><p>Observational data collected in December 2014 at the base camp of Mount Everest, Nepal, indicated frequent new particle formation events of pure biogenic origin. Those events were speculated to be controlled by the along-valley winds forming in the valley connecting the Indo-Gangetic plain to the observational site, the Nepal Climate Observatory-Pyramid. The valley winds funnel highly oxygenated organic molecules of biogenic origin to higher elevations where they nucleate. The mechanism was referred to as \"The Himalayan aerosol factory\". Its geographical extent and climate implications are currently unknown. In view of this, we conducted numerical chemical model simulations to corroborate the presence of the mechanism, and to quantify its geographical extent. Our numerical simulations confirmed that biogenic emissions located in the valleys can be converted into ultra-low volatility organic compounds, transported to the observational site by the along-valley winds, and therein nucleate. The overall time scale of the process, from the release of biogenic emissions to the conversion to ultra-low volatile organic compounds to the arrival time at the observational site, was found to be around 4 hours, consistent with the predicted along-valley winds intensity and the geographical distribution of biogenic emissions. A first estimation of the maximum injection height of biogenic particles, and highly oxygenated organic molecules, indicated the presence of efficient nucleating gases and biogenic particles at an elevation as high as 5000-6000 m a.s.l. These results suggest that the Himalayan chain, under specific weather conditions, is a main contributor to the biogenic aerosol loads in the free troposphere. Considering these findings, field campaigns, especially at the entrance of the valley's floors, and research consortia supporting atmospheric research in Asian mountain regions, are highly encouraged.</p>","PeriodicalId":76,"journal":{"name":"Faraday Discussions","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11922043/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143655666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multiphase sulfur chemistry facilitates particle growth in a cold and dark urban environment.","authors":"Jingqiu Mao, Kunal Bali, James R Campbell, Ellis S Robinson, Peter F DeCarlo, Amna Ijaz, Brice Temime-Roussel, Barbara D'Anna, Damien Ketcherside, Robert J Yokelson, Lu Hu, Meeta Cesler-Maloney, William R Simpson, Fangzhou Guo, James H Flynn, Jason M St Clair, Athanasios Nenes, Rodney J Weber","doi":"10.1039/d4fd00170b","DOIUrl":"https://doi.org/10.1039/d4fd00170b","url":null,"abstract":"<p><p>Sulfate comprises an average of 20% of the ambient PM_2.5 mass during the winter months in Fairbanks, based on 24-hour filter measurements. During the ALPACA 2022 field campaign (Jan 15th-Feb 28th of 2022), we deployed two aerosol mass spectrometers (AMS) and one aerosol chemical speciation monitor (ACSM) at three urban sites, combined with Scanning Mobility Particle Sizers (SMPS), to examine the evolution of aerosol composition and size distribution at a sub-hourly time scale. During an intense pollution episode with ambient temperature between -25 and -35 °C, all three instruments (two AMS and one ACSM) recorded a sharp increase in sulfate mass, ranging from 5 to 40 μg m^-3 within a few hours. This increase contributed up to half of the observed rise in ambient PM_2.5 mass concentration and coincided with a substantial shift in the number distribution from particle sizes less than 100 nm diameter (<i>D</i>_p < 100 nm) to larger particles (<i>D</i>_p > 100 nm) with little increase in number concentration. The corresponding increase in the volume concentration and distribution shift to larger particle size suggests the secondary formation of sulfate and organic aerosol onto pre-existing aerosols. Comparing AMS-sulfate (all sulfur species) to inorganic sulfate measured by online particle-into-liquid sampler-ion chromatography (PILS-IC), we find roughly 80% of sulfate increase was due to organic sulfur, consistent with the observation of mass spectral signatures in the AMS of organosulfur compounds. The rapid formation of sulfate appears to coincide with spikes in ambient aldehyde concentrations (formaldehyde and acetaldehyde) and an increase in S(IV) in ambient PM_2.5. This likely results from multiphase chemistry, where hydroxymethanesulfonate (HMS) and other aldehyde-S(IV) adducts are formed through reactions between aldehydes and SO₂ in deliquesced aerosols. We estimate that all S(IV) species, including HMS, contribute an average of 30% to aerosol sulfur, with a dominant fraction occurring during rapid sulfate increase events. Our work highlights the crucial role of controlling aldehydes to mitigate severe air pollution events in Fairbanks and may apply to other urban areas. It also emphasizes the significance of multiphase chemistry in driving particle growth from Aitken mode to accumulation mode, a key step for aerosol-cloud interactions.</p>","PeriodicalId":76,"journal":{"name":"Faraday Discussions","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143655665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Elucidating how trace gases interact with ice surfaces utilizing sum frequency generation spectroscopy.","authors":"Gurivi Reddy Yettapu, Luca B Manning, Jenée D Cyran","doi":"10.1039/d4fd00157e","DOIUrl":"https://doi.org/10.1039/d4fd00157e","url":null,"abstract":"<p><p>The interaction between ice surfaces and trace gases plays a significant role in atmospheric chemistry, such as chemical and photochemical reactions contributing to ozone depletion and secondary aerosol formation. The study of molecular-level properties of the ice surface and small organic molecule adsorption, are essential to understand the impact of hosting these molecules and further chemical reactions. To capture a molecular understanding of the interface, the use of a surface selective technique, such as sum frequency generation (SFG) spectroscopy, is crucial to probe ice surfaces and observe the adsorption of molecules on ice surfaces. We observe significant differences in the structure of the water molecules for ice and water surfaces upon the addition of acetone and methanol. At the methanol-ice interface, a blue shift of ∼80 cm^-1 is observed, indicating a weakening of the hydrogen bond. This is an opposing shift to the acetone-ice interface, which red shifted by ∼10 cm^-1. These changes in the fundamental frequencies could impact atmospheric models and in particular impact overtone pumping reactions. The distinct behavior of water molecules and small oxygenated organic compounds is linked to differences in reactivity and rates of photochemical reactions <i>via</i> overtone pumping on ice and water surfaces.</p>","PeriodicalId":76,"journal":{"name":"Faraday Discussions","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143595810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biotic and abiotic factors controlling isoprene, DMS, and oxygenated volatile organic compounds (VOCs) at the Southern Ocean in the Austral fall.","authors":"Saewung Kim, Roger Seco, Daun Jeong, Alex Guenther, Kitae Kim, Ahra Mo, Jung-Ok Choi, Jisoo Park, Keyhong Park","doi":"10.1039/d4fd00168k","DOIUrl":"https://doi.org/10.1039/d4fd00168k","url":null,"abstract":"<p><p>We present shipborne observations of volatile organic compounds such as dimethylsulfide (DMS), isoprene, acetaldehyde, acetone, and methanol over the Southern Ocean in April and May 2018. During the cruise, we encountered air masses influenced by the open ocean, coastal Antarctica, and sea ice. No direct correlation between oceanographic parameters and ambient distributions of VOCs is found. Nonetheless, the previously reported correlations among the observed VOCs are found in our observed dataset. The statistically meaningful (<i>R</i>² > 0.2) anti-correlation of DMS with acetone and methanol is consistent with the previous report about biological activities associated with DMS emission and uptake of methanol and acetone. A positive correlation for isoprene and acetaldehyde, notably in the air masses originating from coastal Antarctica, indicates that photolysis of dissolved organic matter (DOM) was the likely source for the compounds when we conducted the observations. In addition, the observed VOCs were often enhanced over the sea ice observations. This can be accounted for by the ventilation processes of the dissolved VOCs under the ice.</p>","PeriodicalId":76,"journal":{"name":"Faraday Discussions","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143584023","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Low-cost electrochemical gas sensing of vertical differences in wintertime air composition (CO, NO, NO₂, O₃) in Fairbanks, Alaska.","authors":"Tjarda J Roberts, Meeta Cesler-Maloney, William R Simpson","doi":"10.1039/d4fd00177j","DOIUrl":"https://doi.org/10.1039/d4fd00177j","url":null,"abstract":"<p><p>Wintertime Fairbanks, Alaska, experiences episodes of severely poor air quality, when local emissions (<i>e.g.</i>, home-heating, vehicular) are enhanced by cold conditions and are trapped by temperature inversions. Monitoring of atmospheric composition, and in particular vertical gradients in composition, is challenging under cold Arctic conditions. This study demonstrates that multiple sets of low-cost electrochemical sensors can provide accurate measurement of CO, NO, NO₂, and O₃ air composition across wide-ranging cold Arctic temperatures (0 °C to -30 °C). The sensors quantify vertical gradients in downtown Fairbanks' atmospheric composition during winter 2021. Low-cost electrochemical sensors (with temperature co-measured) were characterised by cross-comparison to a regulatory air-quality monitoring site. We demonstrate excellent agreement of the electrochemical sensors with the reference monitors (<i>R</i>² > 0.86-0.98), with mean absolute errors <5 ppbv (NO, NO₂, O₃) and <50 ppbv (CO) over gas-ranges of 10-100's, and 3000 ppbv, respectively, sufficient for using the low-cost electrochemical sensors to quantitatively investigate NO-NO₂-O₃ atmospheric chemistry. During four weeks in February-March 2021, sensors placed on the rooftop (20 m) and base (3 m) of a building in downtown Fairbanks identified strong gradients in atmospheric composition over a very short <20 m vertical scale at times when near-surface temperature inversions were present. At night, CO and NO_<i>x</i> were more concentrated at the surface than aloft, and surface ozone was depleted whilst sometimes being present aloft. During the daytime, when solar radiation heated the surface, inversions were disrupted by efficient vertical mixing that mixed in ozone-rich air from above. The low-cost sensor observations demonstrate that near-surface pollutant trapping was correlated with thermal inversions and trace O₃-NO_<i>x</i> atmospheric chemistry, and quantify a local O_<i>x</i> source from direct \"primary\" NO₂ emissions, with a directly emitted NO₂ : NO_<i>x</i> ratio of 0.13 mol mol^-1. The sensors also characterise NO_<i>x</i> emissions, finding a NO_<i>x</i> : CO of 0.15 mol mol^-1. When well-characterised, low-cost electrochemical sensors can provide valuable measurements of local emissions and vertically-resolved atmospheric composition, with sufficient accuracy to trace atmospheric chemistry in cold and stable wintertime urban environments.</p>","PeriodicalId":76,"journal":{"name":"Faraday Discussions","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143571694","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Uptake of ammonia by ice surfaces at atmospheric temperatures.","authors":"Clemens Richter, Shirin Gholami, Yanisha Manoharan, Tillmann Buttersack, Luca Longetti, Luca Artiglia, Markus Ammann, Thorsten Bartels-Rausch, Hendrik Bluhm","doi":"10.1039/d4fd00169a","DOIUrl":"10.1039/d4fd00169a","url":null,"abstract":"<p><p>We present an ambient pressure X-ray photoelectron spectroscopy investigation of the adsorption of ammonia on ice over the temperature range -23 °C to -50 °C. Previous flow tube studies have shown significant uptake of ammonia to ice at these temperatures, which was linked to the incorporation of ammonium into the ice crystal lattice. Our present investigation shows a significant uptake of ammonia to the ice interface, with ammonia concentrations exceeding those measured in past studies for the case of bulk snow and ice. We also have indication that some of the ammonia is protonated at the ice surface and thus adsorbed there as ammonium ions. The impact of high ammonia concentrations at the air-ice interface on the surface chemistry of ice clouds is discussed. The present study lays the groundwork for investigating the reaction of adsorbed ammonia with other trace gases in the atmosphere, which is demonstrated with the example of a proof-of-principle experiment of ammonia's interaction with acetic acid.</p>","PeriodicalId":76,"journal":{"name":"Faraday Discussions","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11883511/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143565546","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modeling attainment in Fairbanks, Alaska, for the wintertime PM_2.5 24-hour non-attainment area using the CMAQ (community multi-scale air quality) model.","authors":"Deanna Huff, Tom Carlson, Lakshmi Pradeepa Vennam, Chao-Jung Chien, Kathleen Fahey, Robert Gilliam, Nick Czarnecki","doi":"10.1039/d4fd00158c","DOIUrl":"https://doi.org/10.1039/d4fd00158c","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Fairbanks Alaska has some of the highest recorded levels of fine particulate matter (PM&lt;sub&gt;2.5&lt;/sub&gt;) in the United States (U.S.), exceeding health-based standards since 2009. The National Ambient Air Quality Standard (NAAQS) in the U.S. for 24 h PM&lt;sub&gt;2.5&lt;/sub&gt; is 35 μg m&lt;sup&gt;-3&lt;/sup&gt; with a 24 h averaging time and takes the form of the 98th percentile averaged over three years; the three-year average is called a design value. Monitored PM&lt;sub&gt;2.5&lt;/sub&gt; level design values have been as high as 135 μg m&lt;sup&gt;-3&lt;/sup&gt; or almost 4 times higher than the health-based standard. The current monitored PM&lt;sub&gt;2.5&lt;/sub&gt; value for 2021-2023 is 56 μg m&lt;sup&gt;-3&lt;/sup&gt;. Fairbanks winters have strong temperature inversions, trapping pollutants near the ground and leading to elevated concentrations of PM&lt;sub&gt;2.5&lt;/sub&gt; and its precursor gases. The two largest species component contributors to PM&lt;sub&gt;2.5&lt;/sub&gt; in Fairbanks are organic carbon and sulfate. Control strategies have focused on reducing organic carbon through wood-stove measures and SO&lt;sub&gt;2&lt;/sub&gt; through fuel sulfur reductions. State Implementation Plans (SIPs) are mandatory plans that demonstrate the most expeditious path to reaching the health-based standard. In previous SIPs, the Alaska Department of Environmental Conservation (ADEC) based attainment demonstrations on an outdated modeling platform, emissions inventory, meteorological data, and episodes. Recent updates include upgrading to the CMAQ (Community Multi-Scale Air Quality) model version 5.3.3+ and updated Weather Research and Forecast (WRF) meteorology resulting from a collaboration with the United States Environmental Protection Agency Office of Research and Development (EPA-ORD) and recent Alaska Layered Pollution and Chemical Analysis (ALPACA) studies. In addition, there have been updates to the emissions inventory (survey, census, parcel and home-heating energy demand model) for space heating and other pre-processing models. The changes have resulted in improved model performance in representing stable boundary layers in meteorology and Model Performance Evaluation (MPE) of secondary sulfate. Modeled secondary sulfate went from underpredicting 88% of the observed sulfate values using the previous modeling platform, to improved sulfate predictions with only a 2.5% Normalized Mean Bias (NMB) and 40% Normalized Mean Error (NME). Using the sulfur tracking method, CMAQ modeling suggests that in Fairbanks, 60% of the sulfate is primary, and 40% is secondary on average for our wintertime modeling period. The modeled primary and secondary fractions of sulfate are corroborated by Moon &lt;i&gt;et al.&lt;/i&gt; 2024 (&lt;i&gt;ACS ES&T Air&lt;/i&gt;, 2024, &lt;b&gt;1&lt;/b&gt;, 139-149), showing 62% of the ambient measured sulfate particles were primary and 38% were secondary in Fairbanks, during the ALPACA field campaign. The combination of these updates to emissions, meteorology and the modeling platform have allowed ADEC to accurately represent modeling of control strategi","PeriodicalId":76,"journal":{"name":"Faraday Discussions","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143555386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Iodine speciation in snow during the MOSAiC expedition and its implications for Arctic iodine emissions.","authors":"Lucy V Brown, Ryan J Pound, Matthew R Jones, Matthew J Rowlinson, Rosie Chance, Hans-Werner Jacobi, Markus M Frey, Stephen D Archer, Stefanie Arndt, Johannes G M Barten, Byron W Blomquist, Ruzica Dadic, Laurens N Ganzeveld, Henna-Reetta Hannula, Detlev Helmig, Matthias Jaggi, Daniela Krampe, Amy R Macfarlane, Shaun Miller, Martin Schneebeli, Lucy J Carpenter","doi":"10.1039/d4fd00178h","DOIUrl":"10.1039/d4fd00178h","url":null,"abstract":"<p><p>Photochemical release of iodine from snow has been suggested as a source of reactive iodine to the Arctic atmosphere, however understanding of the underlying mechanism and potential source strength is hindered by a lack of measurements of iodine concentration and speciation in snow. Moreover, the origin of snow iodine is also unknown. Here, we report iodine speciation measurements in Arctic snow on sea ice at a range of snow depths from 177 samples, representing 80 sampling events, from December 2019 to October 2020 collected during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition. We demonstrate that while there appears to be a source of iodine, in particular iodate, to the base of the snow over first year ice, this does not influence iodine concentration in the surface snow. There is instead evidence of a top-down source of iodine, potentially from iodine-enriched marine aerosol, as well as some evidence for episodic influx of iodate with dust. The potential for photochemical release of molecular iodine (I₂) from iodide in surface snow was investigated, and it was demonstrated that this could provide an iodine emission flux to the Arctic atmosphere comparable to oceanic fluxes. Knowledge of the prevalence and speciation of iodine in Arctic snow will contribute to better understanding of its contribution to observed concentrations of polar iodine oxide (IO), and hence its contribution to the depletion of tropospheric ozone in the Arctic.</p>","PeriodicalId":76,"journal":{"name":"Faraday Discussions","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11880796/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143555385","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Arctic tropospheric ozone seasonality, depletion, and oil field influence.","authors":"Evelyn M Widmaier, Andrew R Jensen, Kerri A Pratt","doi":"10.1039/d4fd00166d","DOIUrl":"https://doi.org/10.1039/d4fd00166d","url":null,"abstract":"<p><p>Near-surface tropospheric ozone depletion events (ODEs) occur in the polar regions during springtime when ozone reacts with bromine radicals, driving tropospheric ozone mole ratios below 15 ppb (part-per-billion; nmol mol^-1). ODEs alter atmospheric oxidative capacity by influencing halogen radical recycling mechanisms and the photochemical production of hydroxyl radicals (˙OH). Herein, we examined five years of continuous ozone measurements at two coastal Arctic sites: Utqiaġvik, Alaska and ∼260 km southeast at Oliktok Point, within the North Slope of Alaska oil fields. These data informed seasonal ozone trends, springtime ozone depletion, and the influence of oil field combustion emissions. Ozone depletion occurred frequently during spring: 35% of the time at Utqiaġvik and 40% at Oliktok Point. ODEs often occurred concurrently at both sites (40-92% of observed ODEs per year), supporting spatially widespread ozone depletion. Observed ozone depletion timescales are consistent with transport of ozone-depleted air masses, suggesting regional active bromine chemistry. Local-scale ozone depletion affecting individual sites occurred less frequently. Ozone depletion typically coincided with calm winds and had no clear dependence on temperature. Consistently lower ozone mole ratios year-round at Oliktok Point, compared to Utqiaġvik, indicate local-scale ozone titration within the stable boundary layer by nitric oxide (NO˙) combustion emissions in the Arctic oil fields. Oxidation of combustion-derived volatile organic compounds in the presence of NO_<i>x</i> also likely contributes to ozone formation downwind, for example at Utqiaġvik, pointing to complex local and regional impacts of combustion emissions as Arctic anthropogenic activity increases.</p>","PeriodicalId":76,"journal":{"name":"Faraday Discussions","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143555384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"<i>In situ</i> measurements of gas-particle partitioning of organic compounds in Fairbanks.","authors":"Amna Ijaz, Brice Temime-Roussel, Julien Kammer, Jingqiu Mao, William Simpson, Kathy S Law, Barbara D'Anna","doi":"10.1039/d4fd00175c","DOIUrl":"https://doi.org/10.1039/d4fd00175c","url":null,"abstract":"<p><p>Organic compounds were measured in both the gas and particle phases in Fairbanks, Alaska, using a real-time, high-resolution proton transfer reaction-time of flight mass spectrometer (PTR-ToF MS) during a wintertime campaign. The organic aerosol (OA) was dominated by semi-volatile organic compounds (SVOCs), followed by compounds in the low-volatile bin (LVOCs). Due to the persistently cold conditions, both heavy and highly oxygenated compounds showed a limited shift in partitioning with temperature change. In contrast, some semi-volatile compounds, such as methoxy phenols from wood combustion, presented some partitioning to the particle phase at lower temperatures. Laboratory studies or theoretical efforts rarely explore gas-particle partitioning at extremely low temperatures, and thus, their applicability under complex meteorological conditions remains to be assessed. A comparison of the observed and estimated volatilities at temperatures from 5 to -33 °C revealed a clear disagreement, with higher estimated volatility for light molecules (<i>m</i>/<i>z</i> below 120) and lower volatilities for heavier compounds (<i>m</i>/<i>z</i> above 300) with respect to the observed ones. Our findings from the Fairbanks winter campaign stress the need to extend the breadth of environmentally relevant conditions under which phase partitioning of organic compounds is generally explored.</p>","PeriodicalId":76,"journal":{"name":"Faraday Discussions","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143539655","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}