ACS ES&T Air最新文献

{"title":"Comparison of Chemical Transport Model and Observation Derived Ozone-NOx-VOC Isopleths for the South Coast Air Basin of California","authors":"Zongrun Li,&nbsp;Yu Qian,&nbsp;Yongtao Hu,&nbsp;Petros Vasilakos,&nbsp;M. Talat Odman,&nbsp;Armistead G. Russell","doi":"10.1021/acsestair.6c00227","DOIUrl":"https://doi.org/10.1021/acsestair.6c00227","url":null,"abstract":"<p>We developed, applied, evaluated, and compared chemicaltransportmodel-based and observation-based methods for constructing ozone isoplethsused to understand ozone-emission relationships, focusing on the SouthCoast Air Basin of California (SoCAB). The High-order Decoupled DirectMethod (HDDM) embedded in the Community Multiscale Air Quality (CMAQ)model was applied under different emission levels to map out the sensitivitiesof ozone levels to anthropogenic emissions of nitrogen oxides (NO_<em>x</em>) and volatile organic compounds (VOCs).Ozone concentrations and sensitivities to emissions simulated by CMAQ-HDDMwere used to develop ozone isopleth diagrams for monitoring locationsacross the SoCAB, and those isopleths were compared with observation-derivedisopleths. The CMAQ-HDDM- and observation-derived isopleths reproducedthe observed ozone concentrations (<em>R</em>² =0.70 and 0.96, respectively) and showed better agreement, especiallyat inland locations, which typically experience higher ozone levelsthan central or coastal sites. The responses of ozone to NO_<em>x</em> and VOC emissions were compared over time, basedon historical VOC and NO_<em>x</em> emission levels.The sensitivities to NO_<em>x</em> emissions showeda stronger correlation (<em>R</em>² = 0.75) betweenthe CMAQ-HDDM- and observation-derived methods than the sensitivitiesto VOC emissions (<em>R</em>² = 0.18). For mostregions in SoCAB, both the CMAQ-HDDM- and observation-derived isoplethsindicate that the ozone regime has transitioned from VOC-limited toNO_<em>x</em>-limited around the late 2000s. Asa result, for equal absolute emission changes, further reductionsin NO_<em>x</em> emissions are more effective thancomparable VOC controls in achieving future ozone decreases, withgreater confidence for inland cities in the SoCAB.</p>","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"3 10","pages":"2767–2780"},"PeriodicalIF":0.0,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149153048","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Combustion Conditions are the Major Drivers of the Variability in Organic Aerosol Chemical Composition and Secondary Organic Aerosol Formation in Emissions from Simulated Wildland Fires","authors":"Muhammad I. Abdurrahman,&nbsp;Michael T. Caraway,&nbsp;Nicholas Kusumo,&nbsp;Thomas Carroll,&nbsp;Kruthika V. Kumar,&nbsp;Anita Anosike,&nbsp;Ariana M. Deegan,&nbsp;Ryan P. Poland,&nbsp;John T. Allen,&nbsp;Mac A. Callaham,&nbsp;Joseph J. O’Brien,&nbsp;Edward C. Fortner,&nbsp;Amanda Frossard,&nbsp;Geoffrey D. Smith,&nbsp;Rawad Saleh","doi":"10.1021/acsestair.6c00258","DOIUrl":"https://doi.org/10.1021/acsestair.6c00258","url":null,"abstract":"<p>Wildland-fire emissions exhibit large variability inaerosol physicochemicalproperties and potential for forming secondary organic aerosol (SOA).Whether this variability is primarily driven by differences in fueltype or combustion conditions remains unresolved. To address thisgap, we performed simulated wildland-fire experiments using fuel bedsthat contained either surface fuels only or a duff layer underneaththe surface fuels. We varied the dry mass loading and moisture contentof the surface fuels within ranges encountered in prescribed firesin the Southeastern U.S. Less efficient combustion, which resultedfrom increased dry mass loading, increased moisture content, or includingduff in the fuel bed, produced less light-absorbing organic aerosol(OA) and formed more SOA. Including duff also produced OA with highernitrogen content. A proof-of-concept experiment using surface fuelsconditioned to reproduce inefficient combustion conditions similarto those of duff emitted OA with nitrogen content, light-absorptionproperties, and SOA formation potential comparable to those of duffOA emissions. Given the profound differences in molecular compositionbetween surface fuels and duff, these results provide strong evidencethat the difference in combustion conditions between duff and surfacefuels was the major driver of the observed differences in OA physicochemicalproperties and SOA formation potential.</p>","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"3 10","pages":"2843–2858"},"PeriodicalIF":0.0,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149152848","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Germicidal UV for the Control of Airborne Bacteria and Viruses: A Critical Review of Efficacy and the Production of Secondary Pollutants","authors":"Robert Groth,&nbsp;Sadegh Niazi,&nbsp;Henry P. Oswin,&nbsp;Kirsten Spann,&nbsp;Sasho Gligorovski,&nbsp;Edward A. Nardell,&nbsp;Helen Cox,&nbsp;Simon A. Joosten,&nbsp;Suman S. Majumdar,&nbsp;Siddhanth Sharma,&nbsp;Vinay J. Menon,&nbsp;Jason Monty,&nbsp;Lidia Morawska,&nbsp;Zoran Ristovski","doi":"10.1021/acsestair.6c00196","DOIUrl":"https://doi.org/10.1021/acsestair.6c00196","url":null,"abstract":"<p>Germicidalultraviolet radiation (GUV) has long beena promisingsolution to indoor transmission of airborne diseases, but has notyet seen widespread adoption. This review addresses: the efficacyof GUV in inactivating airborne pathogens in laboratory experiments;the effect of pathogen structural characteristics and taxonomy onGUV susceptibility; and evidence that GUV produces airborne pollutants,all of which are key challenges to the widespread adoption of thistechnology. With respect to the first objective, the median susceptibilityconstants <em>Z</em> for viruses and bacteria across all wavelengthswere 2.2 cm² mJ^–1 and 3.5 cm² mJ^–1, respectively. GUV using 222 nm radiationhas higher exposure thresholds than 254 nm, which permits a higherdose and is therefore likely more efficacious in practice. For thesecond objective, there is a difference in efficacy between bacterialfamilies, dependent on cell wall characteristics, but there are notenough studies on viruses to determine whether their structural propertiesinfluence UV susceptibility. For the third objective, both 222 and254 nm can generate air pollutants that differ in composition, quantity,and production pathways, and under some conditions can be at harmfullevels. However, operating the devices at fluence rates within guidelinelimits and with adequate ventilation appears to greatly mitigate therisk of pollutant accumulation. The potential for human harm fromthese pollutants, however, is still concerning and requires a combinationof adequate ventilation, consistent monitoring, and intelligent buildingsystems to completely safeguard against human exposure to high levelsof pollutants over prolonged periods. Exposure to high concentrationsof pollutants leads to morbidity, and so confidence in the abilityto prevent pollutant accumulation must be absolute prior to the implementationof GUV.</p>","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"3 10","pages":"2484–2502"},"PeriodicalIF":0.0,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149152909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Estimation of Total VOC Emission and Ozone Removal Rates in a Primary School Classroom","authors":"Eleni Dovrou,&nbsp;Ioannis D. Apostolopoulos,&nbsp;Silas Androulakis,&nbsp;Christos Kaltsonoudis,&nbsp;Angeliki Matrali,&nbsp;Georgia A. Argyropoulou,&nbsp;Spyros N. Pandis","doi":"10.1021/acsestair.6c00224","DOIUrl":"https://doi.org/10.1021/acsestair.6c00224","url":null,"abstract":"<p>Measurements of gaseous and particulate pollutants wereconductedinside and outside a classroom in an urban area of Athens, Greece,using both reference instruments and low cost sensors. These datawere used to evaluate indoor air quality and to estimate the emissionsof total volatile organic compounds (VOCs) inside the classroom. Theaverage air exchange rate during classes was estimated at 6.4 h^–1, based on the CO₂ concentration measurements.Paints, craft materials, and cleaning products have been identifiedas major indoor sources of VOCs. Total VOC emission rates varied dependingon the type of class activities, with an average value of 1.3 mg min^–1 during classes. Emitted VOCs included formaldehyde,acetaldehyde, acetone, methanol, ethanol, C8–C9 aromatics,etc. A classroom indoor air quality model reproduced the observedindoor concentrations of carbon monoxide, nitrogen dioxide, and fineparticulate matter, assuming that outdoor sources were the only sourceof these pollutants. The average ozone removal rate constant was estimatedat 10 h^–1 during classes.</p>","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"3 10","pages":"2755–2766"},"PeriodicalIF":0.0,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149153059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"PFAS in the Urban Atmosphere Detected with I-CIMS and LC-ESI Orbitrap Mass Spectrometer","authors":"Lee Tiszenkel,&nbsp;Vignesh Vasudevan-Geetha,&nbsp;Zachary Watson,&nbsp;James Flynn,&nbsp;Shan-Hu Lee","doi":"10.1021/acsestair.6c00191","DOIUrl":"https://doi.org/10.1021/acsestair.6c00191","url":null,"abstract":"<p>Per- and polyfluoroalkylsubstances (PFAS) are persistentpollutantswhose atmospheric fate in urban areas remains poorly characterized.We combined in-situ iodide CIMS with targeted offline LC-ESI OrbitrapMS to quantify 22 gas- and particle-phase PFAS in Houston, Texas.We calibrated I-CIMS for 18 PFAS and validated it against LC-ESI OrbitrapMS across 9 co-detected particle-phase compounds. Gas-phase ΣPFASreached 2.2 pptv (17.7 ng m^–3) and particle-phaseΣPFAS reached 0.25 pptv (3.1 ng m^–3), with4:2 FTOH, PFPrA, and TFA peaking at 2 to 3 pptv in the gas-phase,among the highest reported in urban atmospheres. Gas-phase PFAS correlatedwith temperature and ozone, while particle-phase PFAS correlated withhumidity. The relationship between particle-associated fraction andsubcooled liquid vapor pressure was shifted roughly two orders ofmagnitude relative to wintertime Toronto, and a further two ordersrelative to indoor environments, demonstrating that aqueous aerosolmodulates PFAS gas-particle equilibrium under humid subtropical conditions.Comparison with Huntsville, Alabama, revealed an inverted PFCA chain-lengthdistribution, demonstrating that local emissions can override regionaland seasonal trends in PFAS composition. These results extend theatmospheric PFAS gas-particle partitioning framework to subtropicalurban environments and demonstrate the value of combined online-offlinemeasurements for characterizing urban PFAS loadings.</p>","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"3 10","pages":"2811–2826"},"PeriodicalIF":0.0,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149153041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Significant Emissions of Phenol and Alkylphenols from Heavy-Duty Diesel Vehicles, Their Dynamic Dispersion, and Human Exposure in Near-Road Microenvironments","authors":"Xiao He,&nbsp;Xuan Zheng,&nbsp;Lewei Zeng,&nbsp;Pengfei Gao,&nbsp;Yuhuan Ding,&nbsp;Yuying Liang,&nbsp;Yifei Dai,&nbsp;Kezheng Liao,&nbsp;Hongyu Lin,&nbsp;Zhiyuan Li,&nbsp;Qifan Liu,&nbsp;Haobing Liu,&nbsp;Sheng Xiang,&nbsp;Shaojun Zhang,&nbsp;Jingkun Jiang,&nbsp;Ye Wu","doi":"10.1021/acsestair.6c00219","DOIUrl":"https://doi.org/10.1021/acsestair.6c00219","url":null,"abstract":"<p>This study identified and characterized a series of alkylphenols(APs) emitted from heavy-duty diesel vehicles (HDDVs) using two-dimensionalgas chromatography mass spectrometry, simulated their near-road dispersion,and estimated population exposure in near-road microenvironments.It was revealed that APs, including nonyl- and octyl-substituted homologs,represented a non-negligible fraction of semi-volatile organic emissionswith diverse structural and toxicological features. A systematic reductionin AP emissions was observed with the progressive tightening of emissionstandards, decreasing from 28.5–35.1 mg km^–1 to 6.6–16.8 mg km^–1, and further to 2.0–4.7mg km^–1 for China IV, V, and VI vehicles, respectively.Structural analysis further suggested that APs with bulky alkyl orbisphenol-like moieties exhibit stronger endocrine-disrupting andpotential carcinogenic characteristics. Dispersion modeling revealeddistinct diurnal concentration patterns, with maximum levels around07:00 a.m. resulting from morning rush-hour traffic emission. Thisoverlap between peak emissions and high population density indicateda critical exposure window for commuters and roadside residents. Theestimated daily intakes (EDIs) of near-road APs via air inhalationwere 1.75, 2.09, 1.21, 0.76, and 0.74 ng (kg_bw day)⁻¹ for infants, toddlers, children, teenagers, and adults,respectively, which were substantially higher than EDIs reported underambient environments, indicating strong exposure risks, particularlyfor toddlers with higher metabolic and respiratory rates. These findingshighlight the emerging significance of APs as traffic-related semi-volatilepollutants with health relevance and underscore the need for theirinclusion in vehicular emission monitoring networks, toxicologicalevaluation, and source-specific regulatory frameworks.</p>","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"3 10","pages":"2721–2731"},"PeriodicalIF":0.0,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149153005","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"How Many PM2.5 Sensors are Needed to Estimate Daily and Annual Deployed-Network Mean Concentrations in City-Scale Sensor Networks?","authors":"Trailokaya Raj Bajgain,&nbsp;Zachary D. Calhoun,&nbsp;Sachchida Nand Tripathi,&nbsp;Abdus Salam,&nbsp;Vaishali Jain,&nbsp;Sandeep Madhwal,&nbsp;Shahid Uz Zaman,&nbsp;Shatabdi Roy,&nbsp;Michael Bergin,&nbsp;David Carlson","doi":"10.1021/acsestair.6c00035","DOIUrl":"https://doi.org/10.1021/acsestair.6c00035","url":null,"abstract":"<p>Low-cost PM_2.5 sensors make it possible todeploy densenetworks, but the density required depends on the monitoring objectiveand local variability. We examined how well smaller subnetworks reproducedeployed-network daily and annual or study-period mean concentrationsusing data from Dhaka, Bangladesh (<em>N</em> = 35; annualmean 55.15 μg/m³), Lucknow, India (<em>N</em> = 71; annual mean 61.80 μg/m³), and the nine-monthOpen Air Chicago network (<em>N</em> = 277; period mean 10.24μg/m³). For each subnetwork size <em>n</em> ≥ 2, mean estimates from 10,000 simple-random-without-replacementdraws were compared with the corresponding deployed-network mean;the <em>n</em> = 1 errors were enumerated exactly. At <em>n</em> = 10, the period median absolute percentage error (MdAPE)was 3.9%, 5.6%, and 1.9% in Dhaka, Lucknow, and Chicago, respectively,and the across-day median daily MdAPE ranged from 2.6% to 5.8%. Fora single sensor, the period MdAPE ranged from 5.2% to 17.8%, whereasthe corresponding 95th-percentile absolute percentage error (APE)ranged from 18.5% to 59.9%, demonstrating that typical and tail performancemust be considered together. Within these three finite networks, <em>n</em> = 10 reproduced the target means with typical errors below6%, although upper-tail performance remained objective- and city-specific.Estimating neighborhood-scale gradients, hotspots, exceedance classification,and population exposure, however, requires network designs tailoredto those objectives. Overall, approximately 10 well-maintained, spatiallydistributed sensors recover annual and typical daily means with anMdAPE below 10%.</p>","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"3 10","pages":"2513–2525"},"PeriodicalIF":0.0,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149152865","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Automated Benchmarking Identifies Topic-Dependent Accuracy of Large Language Models Applied for Indoor Air Quality","authors":"Aijia Zhou,&nbsp;Nhan Dinh Ngo,&nbsp;Lam Khang Nguyen Duy,&nbsp;Yile Huang,&nbsp;Kok-Seng Wong,&nbsp;Haoran Yu,&nbsp;Thanh H. Nguyen","doi":"10.1021/acsestair.6c00152","DOIUrl":"https://doi.org/10.1021/acsestair.6c00152","url":null,"abstract":"<p>Indoor air quality (IAQ) is a major public health concernbecausemodern urban residents spend around 90% of their daily lives indoors.Key concerns include controlling pollutant emissions, managing contaminants,and maintaining the ventilation or filtration performance. With theincreasing prevalence of large language models (LLMs), IAQ researchersand building engineers may rely on them to guide their decisions.However, the reliability of these tools remains unclear. We benchmarkednine recently released LLMs─spanning closed- and open-weightarchitectures─against 174 expert-verified conceptual IAQ questionsmanually derived from authoritative textbooks and peer-reviewed literature.To capture variability in model responses, we tested each questionacross five independent trials. Outputs were then automatically evaluatedagainst reference answers using a hybrid framework that integratedoverlap-based metrics (BLEU, ROUGE-L), semantic similarity (BERT),and AI-as-judge scoring and has been trained and tested against expertassessments to ensure estimation accuracy. Incorporating the AI-basedscoring enhanced the reliability of the automatic evaluation system,especially in identifying incorrect LLM responses. Prompting modelswith domain-specific instructions slightly improved their accuracyand consistency. Importantly, the accuracy of all LLMs dropped below80% for particle impaction and sampling efficiency topics, possiblybecause of limited domain-specific training data and specialized terminologiesinherent to these topics. This study provides systematic benchmarksof commonly used LLMs in the context of IAQ, offering guidance ontheir current capabilities, highlighting areas where reliability isinsufficient, and pointing out the need for fine-tuned models to ensuretrustworthy decision support for certain IAQ topics.</p>","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"3 10","pages":"2629–2639"},"PeriodicalIF":0.0,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149152814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of Cannabis Cultivation on Outdoor Air Quality: Meteorological Drivers in Urban VOC-Limited Regimes","authors":"Davi de Ferreyro Monticelli,&nbsp;Sahil Bhandari,&nbsp;Jasraj Brar,&nbsp;Amanda Giang,&nbsp;Naomi Zimmerman","doi":"10.1021/acsestair.6c00310","DOIUrl":"https://doi.org/10.1021/acsestair.6c00310","url":null,"abstract":"<p>Cannabis cultivationis a source of biogenic volatileorganic compounds(BVOCs), which can contribute to ozone (O₃) formation andgrowth of ultrafine particles (UFPs; &lt;100 nm). This study usedmobile monitoring to evaluate outdoor air quality near a large (440,000m²) commercial cannabis cultivation facility (CCF) in Delta,BC, Canada. Measurements of O₃ and UFPs were collectedduring summer under peak photochemical conditions at urban and Ruralupwind and downwind locations and also on roads directly surroundingthe greenhouses. Dispersion modeling (CALPUFF v7.2.1) was used toestimate the BVOC concentrations. Median O₃ was enhancedby 3 ppb at the downwind Urban area of the CCF. UFP concentrationsincreased by 700% in the greenhouse area when wind transported urbanNO_<em>x</em> emissions toward the CCF. Conversely,UFPs decreased in the Urban area when downwind of the facility, suggestingenhanced formation of more volatile products under high-NO<em>_x</em> conditions. Our results indicate that largeCCFs should be preferentially sited in Rural areas rather than nearurban centers in order to avoid an increase in tropospheric O₃ concentrations. Future mobile monitoring with real-time VOCobservations and boundary layer characterization would improve attributionof secondary pollutant formation near cannabis facilities.</p>","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"3 10","pages":"2871–2884"},"PeriodicalIF":0.0,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149152847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Single-Particle Visualization of Water Uptake of Organic–Inorganic Aerosols with In Situ Transmission Electron Microscopy","authors":"Martin C. Ahn,&nbsp;Yuhang Wang,&nbsp;Amy Chen,&nbsp;Dewansh Rastogi,&nbsp;Kotiba Malek,&nbsp;Liza-Anastasia DiCecco,&nbsp;Jennifer Gray,&nbsp;Akua Asa-Awuku,&nbsp;Taylor Woehl","doi":"10.1021/acsestair.6c00332","DOIUrl":"https://doi.org/10.1021/acsestair.6c00332","url":null,"abstract":"<p>Atmospheric aerosolwater uptake properties influencecloud formationand precipitation, atmospheric chemistry, and global climate. Atmosphericaerosols often contain organic acids and inorganic hygroscopic salts,and their internal mixing influences water uptake properties in complexand nonintuitive ways. The heterogeneous nature of aerosol ensemblesnecessitates nanoscale visualization of aerosol mixing state and wateruptake dynamics to uncover mechanistic details. Here we demonstratethat water uptake in phase separated phthalic acid (PTA)/sodium chloride(NaCl) aerosols proceeds by eutonic mixing and partial NaCl deliquescence,while subsequent drying creates core–shell particles containingnewly formed sodium phthalate salts. Electron tomography and elementalmapping revealed that lab-made PTA/NaCl aerosols contained a cuboidalcrystalline NaCl domain and amorphous PTA domain. Sodium extendedbeyond the NaCl into a ∼10 nm thick chemically distinct interphasebetween NaCl and the bulk PTA, consistent with formation of sodiumphthalate <em>via</em> chloride depletion. Humidity controlled <em>in situ</em> TEM imaging revealed PTA/NaCl aerosols initiallyuptake water by adsorption and swelling of the PTA. Further increasesin humidity caused partial NaCl deliquescence, hygroscopic dropletgrowth, and partial dissolution and morphology changes in the PTA.Dehumidification effected precipitation of an organic-rich solidshell followed by NaCl nanocrystal formation on the residual PTA core,yielding a distinctly different core–shell morphology comparedto the as-made particles. Diffraction and elemental mapping confirmcrystalline sodium acid phthalate forms following dehumidification.This work solidifies our understanding of water uptake and chemicalreactions in mixed organic–inorganic atmospheric aerosols byuncovering multistep water uptake dynamics and new phase formation.</p>","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"3 10","pages":"2885–2897"},"PeriodicalIF":0.0,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149152854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}