Environmental science: atmospheres最新文献

{"title":"Evaluating the variability and consistency of NOx emission regulation between sectors†","authors":"Lucy J. Webster, Alastair C. Lewis and Sarah J. Moller","doi":"10.1039/D4EA00149D","DOIUrl":"https://doi.org/10.1039/D4EA00149D","url":null,"abstract":"<p >The emissions of nitrogen oxides (NO<small>_<em>x</em></small>) from combustion have been regulated for several decades with substantial reductions in national totals being reported in high-income countries since the 1990s. Most technical regulation on emissions is sectoral, appliance specific, and uses metrics aligned to activity data, for example grams of NO<small>_<em>x</em></small> per kilometre driven or grams per kilonewton thrust. It is not straightforward therefore to compare the relative stringency of emission regulation between sectors. Here we undertake a regulatory assessment placing all the key NO<small>_<em>x</em></small> emitting sectors onto a common grams of NO<small>_<em>x</em></small> per kilowatt hour (g<small>_{[NO<small>_<em>x</em></small>]}</small> kWh<small>⁻¹</small>) baseline, covering appliances as small as 1 kW to greater than 2 GW. This common scale facilitates meaningful regulatory comparisons and may help to inform future policy decisions. We find little regulatory consistency between sectors when viewed on a per kWh output basis, with non-road mobile machinery (NRMM), medium combustion plant (MCP), maritime and civil aviation having more permissive regulatory limits when compared to emissions from passenger cars and domestic boilers. This difference can be large for appliances with the same nominal power rating; for example, the allowable NO<small>_<em>x</em></small> emissions for a backhoe loader are 4.3 times higher than those for a passenger car. Transparency in pollutant emissions varies considerably between sectors. Data from MCPs and the Industrial Emissions Directive (IED) are less accessible due to commercial sensitivities and the use of less definitively defined principles of ‘Best Available Techniques’. Whilst electrification is likely in the long-term to eliminate some NO<small>_<em>x</em></small> sources, it is notable that this will be in sectors that currently have more stringent regulatory limits (<em>e.g.</em> road transport, domestic heating). More permissively regulated sectors such as NRMM, MCPs and aviation are likely to retain combustion systems and will continue to emit substantial NO<small>_<em>x</em></small> unless the adoption of low carbon fuel is accompanied by revision of NO<small>_<em>x</em></small> emission standards.</p>","PeriodicalId":72942,"journal":{"name":"Environmental science: atmospheres","volume":" 5","pages":" 603-619"},"PeriodicalIF":2.8,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2025/ea/d4ea00149d?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143949386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterizing highly oxygenated organic molecules in limonene secondary organic aerosols: roles of temperature and relative humidity†","authors":"Yitong Zhai, Vasilios G. Samaras and S. Mani Sarathy","doi":"10.1039/D4EA00153B","DOIUrl":"https://doi.org/10.1039/D4EA00153B","url":null,"abstract":"<p >Highly oxygenated organic molecules (HOMs) are significant contributors to the formation of secondary organic aerosols (SOAs) and new particles in the atmosphere. The process of HOM formation <em>via</em> autoxidation is highly dependent on several factors, such as temperature, relative humidity (RH), and initial ozone concentration, among others. The current work investigates how temperature and RH affect the formation of HOMs in SOAs from limonene ozonolysis. Experiments were conducted in a laminar flow tube reactor under different experimental conditions (<em>T</em> = 5 °C and 25 °C; RH = 15% and 75%). A scanning mobility particle sizer was used to measure the concentration and size distribution of generated SOA particles. Fourier transform ion cyclotron resonance mass spectrometry was used to detect and characterize HOMs and SOAs. Experimental results show that lower temperatures (<em>i.e.</em>, <em>T</em> = 5 °C) and higher RH levels (<em>e.g.</em>, RH = 75%) promote the generation of HOMs and SOAs. Limonene-oxidation-derived HOMs exhibit a preference for stabilization under low-temperature and high-RH conditions. Within this context, semi-volatile, low-volatile, and extremely low-volatile organic compounds play a significant role. Our experimental findings indicate that the formation of C<small>₁₀</small> compounds during limonene ozonolysis is strongly influenced by peroxy radical chemistry. Given that peroxy radicals are key intermediates in this process, their reactions—including autoxidation and bimolecular termination pathways—likely play a significant role in the formation and stabilization of HOMs in SOAs. The observed product distributions also suggest that these radicals contribute to the incorporation of multiple oxygen atoms, facilitating the formation of ELVOCs and LVOCs that ultimately drive particle-phase growth. The present work can improve our understanding of the generation of biogenic HOMs and SOAs at different temperatures and RH, which can be used in future exposure risk or climate models to provide more accurate air quality prediction and management.</p>","PeriodicalId":72942,"journal":{"name":"Environmental science: atmospheres","volume":" 4","pages":" 455-470"},"PeriodicalIF":2.8,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2025/ea/d4ea00153b?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143809082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comment on “Assessing the atmospheric fate of trifluoroacetaldehyde (CF3CHO) and its potential as a new source of fluoroform (HFC-23) using the AtChem2 box model” by Pérez-Peña et al., Environ. Sci.: Atmos., 2023, 3, 1767–1777, DOI: 10.1039/D3EA00120B","authors":"O. J. Nielsen, M. P. Sulbaek Andersen and J. Franklin","doi":"10.1039/D4EA00123K","DOIUrl":"https://doi.org/10.1039/D4EA00123K","url":null,"abstract":"<p >Recently Pérez-Peña <em>et al.</em> published a paper in this journal on the potential atmospheric fate of trifluoroacetaldehyde (CF<small>₃</small>CHO) as a source of CF<small>₃</small>H (HFC-23). In their work they utilized both a box model and a global chemistry and transport model to evaluate the production of CF<small>₃</small>H from the photolysis of CF<small>₃</small>CHO, the latter generated from photochemical oxidation of HFO-1234ze (CF<small>₃</small>CH<img>CHF). Certain chemical assumptions and simplifications were made. We believe the assumptions utilized by Pérez-Peña <em>et al.</em> misrepresent the environmental fate of CF<small>₃</small>CHO. In the following, we present our comments on both the photolysis and the wet and dry deposition of CF<small>₃</small>CHO. Furthermore, we contemplate the impact of the potential deposition of CF<small>₃</small>CHO on the formation of trifluoroacetic acid (CF<small>₃</small>COOH) during the environmental processing of CF<small>₃</small>CHO.</p>","PeriodicalId":72942,"journal":{"name":"Environmental science: atmospheres","volume":" 4","pages":" 530-534"},"PeriodicalIF":2.8,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2025/ea/d4ea00123k?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143809086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reply to the ‘Comment on “Assessing the atmospheric fate of trifluoroacetaldehyde (CF3CHO) and its potential as a new source of fluoroform (HFC-23) using the AtChem2 box model”’ by O. J. Nielsen, M. P. Sulbaek Andersen and J. Franklin, Environ. Sci.: Atmos., 2025, 5, DOI: 10.1039/D4EA00123K","authors":"Maria Paula Pérez-Peña, Jenny A. Fisher, Christopher S. Hansen and Scott H. Kable","doi":"10.1039/D4EA00154K","DOIUrl":"https://doi.org/10.1039/D4EA00154K","url":null,"abstract":"<p >In Pérez-Peña <em>et al.</em> (DOI: https://doi.org/10.1039/d3ea00120b), we used a suite of box model simulations to determine how trifluoroacetaldehyde (CF<small>₃</small>CHO) produced from HFO-1234ze is lost in the atmosphere and how much fluoroform (CHF<small>₃</small> or HFC-23) could potentially be produced as a result. For the first time in any modelling study, our simulations included both a minor CF<small>₃</small>CHO photolytic loss channel leading to CHF<small>₃</small> production and physical removal of CF<small>₃</small>CHO <em>via</em> wet and dry deposition. In their comment, Sulbaek Andersen, Nielsen, and Franklin query the assumptions used to simulate these processes. Here, we show that the importance of the photolytic loss pathway remains a matter of community debate and that our results are relatively insensitive to assumptions underlying simulation of deposition. We reiterate the need for measurements of CF<small>₃</small>CHO physical properties to reduce the uncertainties in these processes and pave the way for more sophisticated models.</p>","PeriodicalId":72942,"journal":{"name":"Environmental science: atmospheres","volume":" 4","pages":" 535-538"},"PeriodicalIF":2.8,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2025/ea/d4ea00154k?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143809087","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Particle size distributions of wildfire aerosols in the western USA†","authors":"Siying Lu, Chiranjivi Bhattarai, Vera Samburova and Andrey Khlystov","doi":"10.1039/D5EA00007F","DOIUrl":"10.1039/D5EA00007F","url":null,"abstract":"<p >Wildfires are a major source of aerosols during summer in the western United States. Aerosols emitted from wildfires could significantly affect air quality, human health, and the global climate. This study conducted a comparison of aerosol characteristics during wildfire smoke-influenced and non-smoke-influenced days. Ambient particle size distribution (PSD) data were collected in Reno, Nevada, between July 2017 and October 2020. During this period, the site was impacted by smoke from over a hundred wildfires burning in a wide range of ecosystems in the western United States located at different distances from the measurement site. The smoke-influenced days were identified using satellite images, a hazard mapping system, and wind back-trajectory. Positive matrix factorization (PMF) was applied to identify the main sources and their characteristics. The wildfire aerosols were observed to have a number mode diameter of 212 nm, which is significantly larger than aerosols on non-smoke-influenced days (61 nm). In addition to the increase in particle size, wildfires made a large contribution to PM<small>_2.5</small> and CO concentrations. During fire-prone months (July, August, and September) from 2016 to 2021, 56% to 65% of PM<small>_2.5</small> and 18% to 26% of CO concentrations could be attributed to wildfire emissions in the study area. On an annual basis, wildfire emissions were responsible for 35% to 47% of PM<small>_2.5</small> concentrations and 5% to 12% of CO concentrations.</p>","PeriodicalId":72942,"journal":{"name":"Environmental science: atmospheres","volume":" 4","pages":" 502-516"},"PeriodicalIF":2.8,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11917463/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143671766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Indoor penetration of ambient particulate pollution in a hospital maternity ward in Manila, Philippines: perspectives towards holistic city-level air quality management†","authors":"Colleen Marciel F. Rosales, Everlyn Gayle Tamayo, Dana Lightha Babela and Maria Preciosa Benjamin","doi":"10.1039/D4EA00160E","DOIUrl":"https://doi.org/10.1039/D4EA00160E","url":null,"abstract":"<p >Several studies have analyzed and reported the relationship between particulate matter (PM) in the air and its adverse health effects, primarily on fetal development and subsequent early childhood. This study aims to understand how outdoor air made up of mainly PM, influences indoor air quality in a naturally ventilated maternity ward in an urban hospital setting. The data collection site in this study was the Dr Jose Fabella Memorial Hospital, a maternity hospital located in Manila, Philippines. Indoor and outdoor PM<small>_2.5</small> levels from November 2021 to June 2022 were investigated. A strong positive correlation (<em>r</em><small>²</small> ranging from 0.78 to 0.98) was observed between the daily outdoor and indoor PM levels. While the median concentrations were above the World Health Organization (WHO) air quality guidelines, they were below the Philippine National Ambient Air Quality Guideline Values (NAAQGV) at the time of data collection. These results underscore the importance of updating guideline values. Indoor-to-outdoor diurnal ratios (<em>I</em>/<em>O</em>), ranging from 0.77 to 1.33, with peak times (indoor-source-dominated) between 12:00 and 13:00 and trough times (outdoor-source-dominated) between 04:00 and 05:00, offered insight into the times of the day dominated by indoor <em>versus</em> outdoor sources and highlighted the need for continuous air monitoring while providing additional protection in indoor spaces, such as clear indoor air quality guidelines combined with indoor ventilation and filtration requirements. These results highlight the need for a holistic air quality management approach which focuses concurrently on both ambient and indoor air quality in healthcare facilities. Naturally ventilated hospitals must be included as a priority monitoring site, as they are a critical in improving air quality in the context of public health protection.</p>","PeriodicalId":72942,"journal":{"name":"Environmental science: atmospheres","volume":" 5","pages":" 563-573"},"PeriodicalIF":2.8,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2025/ea/d4ea00160e?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143949383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Utility of low-cost sensor measurement for predicting ambient PM2.5 concentrations: evidence from a monitoring network in Accra, Ghana†","authors":"Patrick Attey-Yeboah, Christian Afful, Kelvin Yeboah, Carl H. Korkpoe, Eric S. Coker, R. Subramanian and A. Kofi Amegah","doi":"10.1039/D4EA00140K","DOIUrl":"https://doi.org/10.1039/D4EA00140K","url":null,"abstract":"<p >Ambient air pollution has been linked to several health endpoints. The WHO attributes 7 million deaths annually to air pollution with particulate matter (PM<small>_2.5</small>) being the pollutant of critical importance due to its devastating health effects. Air quality monitoring is very limited in sub-Saharan African (SSA) countries and although satellite remote sensing has helped to bridge the huge air quality data gaps, these measurements have not been validated against ground-level measurements in these countries. We therefore evaluated the efficiency of low-cost sensors in estimating PM<small>_2.5</small> concentrations in an African city through comparison of low-cost sensor data with satellite aerosol optical depth (AOD) data leveraging complex machine learning (ML) methods. Low-cost sensor data were collected from a monitoring network in Accra, Ghana, with AOD measurements extracted from the MODIS MCD19A2v061 dataset and processed using the MAIAC algorithm. Ordinary Least Squares regression, Random Forest, Extra Trees, Boosted Decision Trees and XGBoost were used to establish the relationship between AOD and low-cost sensor PM<small>_2.5</small> measurements incorporating meteorological data. We observed significant positive relationships for two low-cost sensors deployed in the network (Clarity Node S and Airnote). The <em>R</em><small>²</small> values were, however, low, ranging from 0.18 to 0.27, with the corrected Airnote data recording the highest <em>R</em><small>²</small>. The ML models which integrated temperature and humidity improved the <em>R</em><small>²</small> values with the Boosted Decision Tree demonstrating the best predictive capability. Seasonal variability was found to have a strong influence on model performances with the dry season model performing significantly better than the wet season model. Consistent with other studies, AOD explained only a small proportion of ground-level PM<small>_2.5</small> variations. Evidence from this sensor network in Accra suggests that AOD predicts ground-level PM<small>_2.5</small> measured with low-cost sensors in a manner similar to conventional air monitoring instrumentation. However, for low-cost sensors to be deemed a good substitute for satellite AOD, data correction with complex algorithms developed in the same research location will be required.</p>","PeriodicalId":72942,"journal":{"name":"Environmental science: atmospheres","volume":" 4","pages":" 517-529"},"PeriodicalIF":2.8,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2025/ea/d4ea00140k?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143809085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of organic hydrotrioxide (ROOOH) formation from RO2 + OH reactions and their atmospheric impact using a chemical transport model, STOCHEM-CRI†","authors":"M. Anwar H. Khan, Rayne Holland, Asan Bacak, Thomas J. Bannan, Hugh Coe, Richard G. Derwent, Carl J. Percival and Dudley E. Shallcross","doi":"10.1039/D5EA00009B","DOIUrl":"https://doi.org/10.1039/D5EA00009B","url":null,"abstract":"<p >Incorporating the reactions of fifty peroxy radicals (RO<small>₂</small>) with the hydroxyl radical (OH) into the global chemistry transport model, STOCHEM-CRI, affected the composition of the troposphere by changing the global burdens of NO<small>_<em>x</em></small> (−2.7 Gg, −0.5%), O<small>₃</small> (−2.3 Tg, −0.7%), CO (−3.2 Tg, −0.8%), HO<small>_<em>x</em></small> (+2.1 Gg, +7.7%), H<small>₂</small>O<small>₂</small> (+0.5 Tg, +18.3%), RO<small>₂</small> (−8.0 Gg, −18.2%), RONO<small>₂</small> (−19.4 Gg, −4.7%), PAN (−0.1 Tg, −3.4%) HNO<small>₃</small> (−7.4 Gg, −1.3%) and ROOH (−96.9 Gg, −3.8%). The RO<small>₂</small> + OH addition reactions have a significant impact on HO<small>₂</small> mixing ratios in tropical regions with up to a 25% increase, resulting in increasing H<small>₂</small>O<small>₂</small> mixing ratios by up to 50% over oceans. Globally, a significant amount of organic hydrotrioxides (ROOOH) (86.1 Tg per year) are produced from these reactions with CH<small>₃</small>OOOH (67.5 Tg per year, 78%), isoprene-derived ROOOH (5.5 Tg per year, 6%) and monoterpene-derived ROOOH (4.2 Tg per year, 5%) being the most significant contributors. The tropospheric global burden of CH<small>₃</small>OOOH is found to be 0.48 Gg. The highest mixing ratios of ROOOH, of up to 0.35 ppt, are found primarily in the oceans near the tropical land areas. The RO<small>₂</small> + OH reactions have a small, but noticeable, contribution to OH reactivity (∼5%) over tropical oceans. Additionally, these reactions have a significant impact on RO<small>₂</small> reactivity over tropical oceans where losses of the CH<small>₃</small>O<small>₂</small> radical, isoprene derived peroxy radical (ISOPO<small>₂</small>) and monoterpene derived peroxy radical (MONOTERPO<small>₂</small>) by OH can contribute up to 25%, 15% and 50% to the total RO<small>₂</small> loss, respectively. The changes in RO<small>₂</small> reactivity influence the global abundances of organic alcohols (ROH) which are important species due to their crucial impact on air quality. The ROOOH generate secondary organic aerosol (SOA) of up to 0.05 μg m<small>⁻³</small> which affects the Earth's radiation budget because of enhancing modelled organic aerosol by up to 5% and 2000% on land surfaces and the remote tropical oceans, respectively.</p>","PeriodicalId":72942,"journal":{"name":"Environmental science: atmospheres","volume":" 4","pages":" 442-454"},"PeriodicalIF":2.8,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2025/ea/d5ea00009b?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143809081","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Integrated air quality information for Kampala: analysis of PM2.5, emission sources, modelled contributions, and institutional framework†","authors":"Deo Okure, Sarath K. Guttikunda, Richard Sserunjogi, Priscilla Adong, Sai Krishna Dammalapati, Dorothy Lsoto, Paul Green, Engineer Bainomugisha and Jian Xie","doi":"10.1039/D4EA00081A","DOIUrl":"https://doi.org/10.1039/D4EA00081A","url":null,"abstract":"<p >Kampala, the political and economic capital of Uganda and one of the fastest urbanizing cities in sub-Saharan Africa, is experiencing a deteriorating trend in air quality. This decline is driven by emissions from multiple diffuse local sources, including transportation, domestic and outdoor cooking, and industries, as well as by sources outside the city airshed, such as seasonal open fires in the region. PM<small>_2.5</small> (particulate matter under 2.5 μm size) is the key pollutant of concern in the city with monthly spatial heterogeneity of 60–100 μg m<small>⁻³</small>. Outdoor air pollution is distinctly pronounced in the global south cities and lack the necessary capacity and resources to develop integrated air quality management programs including ambient monitoring, emissions and pollution analysis, source apportionment, and preparation of clean air action plans. This paper presents the first comprehensive integrated assessment of air quality in Kampala to define a multi-level intervention framework, utilizing ground measurements from a hybrid network of stations, global reanalysis fields from GEOS-Chem and CAMS simulations, a high-resolution (∼1 km) multi-pollutant emissions inventory for the designated airshed, WRF-CAMx-based PM<small>_2.5</small> pollution analysis, and a qualitative review of the institutional and policy environment in Kampala. This collation of information documents baseline data for all known sectors, providing a foundational resource for the development of a clean air action plan. The proposed plan aims for better air quality in the region using a combination of short-, medium-, and long-term emission control measures for all the dominate sources and institutionalize pollution tracking mechanisms (like emissions and pollution monitoring and reporting) for effective management of air pollution.</p>","PeriodicalId":72942,"journal":{"name":"Environmental science: atmospheres","volume":" 4","pages":" 471-484"},"PeriodicalIF":2.8,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2025/ea/d4ea00081a?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143809083","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Vertical gradient in atmospheric particle phase state: a case study over the alaskan arctic oil fields†","authors":"Nurun Nahar Lata, Zezhen Cheng, Darielle Dexheimer, Susan Mathai, Matthew A. Marcus, Kerri A. Pratt, Theva Thevuthasan, Fan Mei and Swarup China","doi":"10.1039/D4EA00150H","DOIUrl":"https://doi.org/10.1039/D4EA00150H","url":null,"abstract":"<p >The phase state of atmospheric particles impacts atmospheric processes like heterogeneous reactions, cloud droplet activation, and ice nucleation, influencing Earth's climate. Factors like chemical composition, temperature, and relative humidity govern particle phase states. The Arctic atmosphere is stratified, with varying particle compositions, but vertical profiles of submicron phase states remain poorly understood due to limited aloft measurements. To address this, particle samples were collected <em>via</em> a tethered balloon system (TBS) at the U.S. Department of Energy Atmospheric Radiation Measurement Program's facility at Oliktok Point, Alaska, on November 19, 2020. Using an environmental scanning electron microscope with a tilted Peltier stage to simulate atmospheric conditions, we probed particle phase states, observing near-spherical, dome-like, and flat shapes upon substrate impact. Particles at an altitude of 300 m contained similar, high fractions of viscous particles (79 ± 9%) compared to ground-level (74 ± 5%). Chemical characterization revealed that carbonaceous-rich and carbonaceous sulfate-rich particles dominate ground-level samples, while 300 m samples included more carbonaceous-rich and carbonaceous-coated dust particles. STXM-NEXAFS further highlighted differences in particle mixing states, with a higher abundance of organic and mixed organic–inorganic particles at both altitudes. Integrating chemical composition and phase state measurements demonstrated that carbonaceous-rich and organic-dominated particles exhibited higher viscosities, while inorganic-rich particles displayed lower viscosities. This finding establishes an association between composition and phase state, offering critical insights into the vertical stratification of Arctic particles.</p>","PeriodicalId":72942,"journal":{"name":"Environmental science: atmospheres","volume":" 4","pages":" 415-428"},"PeriodicalIF":2.8,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2025/ea/d4ea00150h?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143809071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}