Aerosol Research最新文献

{"title":"Vertical concentrations gradients and transport of airborne microplastics in wind tunnel experiments","authors":"E. M. Esders, Christoph Georgi, Wolfgang Babel, Andreas Held, Christoph Karl Thomas","doi":"10.5194/ar-2-235-2024","DOIUrl":"https://doi.org/10.5194/ar-2-235-2024","url":null,"abstract":"Abstract. Microplastics are an ubiquitous anthropogenic material in the environment, including the atmosphere. Little work has focused on the atmospheric transport mechanisms of microplastic nor its dispersion, despite it being a potential pollutant. We study the vertical transport of airborne microplastics in a wind tunnel, a controllable environment with neutral stability, to identify the necessary conditions for the long-range atmospheric transport of microplastics. An ultrasonic disperser generated airborne water droplets from a suspension of polystyrene microsphere microplastics (MPs) with a diameter of 0.51 µm. The water droplets were injected into the airflow, evaporating and releasing single airborne MPs. The disperser allowed for time-invariant and user-controlled concentrations of MPs in the wind tunnel. MPs were injected at 27, 57, and 255 mm above the ground. A single GRIMM R11 optical particle counter (OPC) and three Alphasense OPCs measured time-averaged MP concentration profiles (27, 57, and 157 mm above the ground). These were combined with turbulent airflow characteristics measured by a hotwire probe to estimate vertical particle fluxes using the flux-gradient similarity theory. The GRIMM R11 OPC measured vertical concentration profiles by moving its sampling tube vertically. The three Alphasense OPCs measured particle concentrations simultaneously at three distinct heights. Results show that maximum concentrations are not measured at the injection height but are rather shifted to the surface by gravitational settling. The MPs experience higher gravitational settling while they are part of the larger water droplets. For the lowest injection at 27 mm, the settling leads to smaller MP concentrations in the wind tunnel, as MPs are lost to deposition. Increasing the wind speed decreases the loss of MPs by settling, but settling is present until our maximum friction velocity of 0.14 m s−1. For the highest injection at 255 mm and laminar flow, the settling resulted in a net MP emission, challenging the expectation of a net MP deposition for high injection. Turbulent flows reverse the MP concentration profile giving a net MP deposition with deposition velocities of 3.7 ± 1.9 cm s−1. Recognizing that microplastics share deposition velocities with mineral particles bridges the gap in understanding their environmental behavior. The result supports the use of existing models to evaluate the transport of microplastics in the accumulation mode. The similar deposition velocities suggest that microplastics transported in the atmosphere can be found in the same places as mineral particles.\u0000","PeriodicalId":511317,"journal":{"name":"Aerosol Research","volume":"29 49","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141813916","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":"Direct detection of polycyclic aromatic hydrocarbons on a molecular composition level in summertime ambient aerosol via proton transfer reaction mass spectrometry","authors":"Tobias Reinecke, M. Leiminger, Andreas Klinger, Markus Müller","doi":"10.5194/ar-2-225-2024","DOIUrl":"https://doi.org/10.5194/ar-2-225-2024","url":null,"abstract":"Abstract. Condensed particulate polycyclic aromatic hydrocarbons (PAHs) are a group of toxic organic compounds that are produced by the incomplete combustion of organic material, for example, via biomass burning or traffic emissions. Even at low long-term exposure levels, such as 1 ng m−3 of benzo(a)pyrene, PAHs are recognized to be detrimental to human health. Therefore, a quantitative characterization of PAHs at sub-nanogram-per-cubic-meter levels is important to examine precise long-term exposure. A new ultrasensitive generation of proton transfer reaction mass spectrometry (PTR-MS) instruments coupled to the CHARON particle inlet are capable of quantitatively detecting this toxic class of compounds at a molecular composition level while also offering a high temporal resolution of < 1 min and sub-nanogram-per-cubic-meter limits of detection. To demonstrate the capabilities of this new CHARON FUSION PTR-TOF 10k instrument, we present a thorough characterization of summertime ambient condensed PAHs in Innsbruck, Austria. With a mass resolution of > 14 000 (m Δm−1 at full width at half maximum) and sensitivities of up to 40 cps ng−1 m3 (where cps represents counts per second), a series of nine condensed PAHs of four (C16H10) to six aromatic rings (C26H16) are identified among a plethora of organic compounds in ambient organic aerosol. With 1 min limits of detection between 19 and 46 pg m−3, quantitative time series of these PAHs at the lowermost mass concentrations are determined. To understand the sources and processes associated with these condensed summertime PAHs in greater detail, a matrix factorization including the ∼ 4000 ionic signals detected by the CHARON FUSION PTR-TOF 10k is performed, representing the vast majority of the mass concentration of ambient organic aerosol. A total of 10 factors and their corresponding time series can be identified. Known tracer compounds like levoglucosan, pinonic acid or nicotine consequently allow the assignment to individual organic aerosol sources and physicochemical processes. PAH emissions from traffic are found to be minor contributors during this summertime sampling period. The highest concentrations of PAHs are identified in a mixed aged oxygenated organic aerosol, followed by a biomass burning and a cigarette smoke organic aerosol.\u0000","PeriodicalId":511317,"journal":{"name":"Aerosol Research","volume":" 90","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141824811","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":"Opinion: Eliminating aircraft soot emissions","authors":"Una Trivanovic, S. Pratsinis","doi":"10.5194/ar-2-207-2024","DOIUrl":"https://doi.org/10.5194/ar-2-207-2024","url":null,"abstract":"Abstract. Soot from aircraft engines deteriorates air quality around airports and can contribute to climate change primarily by influencing cloud processes and contrail formation. Simultaneously, aircraft engines emit carbon dioxide (CO2), nitrogen oxides (NOx), and other pollutants which also negatively affect human health and the environment. While urgent action is needed to reduce all pollutants, strategies to reduce one pollutant may increase another, calling for a need to decrease, for example, the uncertainty associated with soot's contribution to net radiative forcing (RF) in order to design targeted policies that minimize the formation and release of all pollutants. Aircraft soot is characterized by rather small median mobility diameters, dm=8–60 nm, and at high thrust, low (< 25 %) organic carbon to total carbon (OC/TC) ratios, while at low thrust, the OC/TC can be quite high (> 75 %). Computational models could aid in the design of new aircraft combustors to reduce emissions, but current models struggle to capture the soot, dm, and volume fraction, fv, measured experimentally. This may partly be due to the oversimplification of soot's irregular morphology in models and a still poor understanding of soot inception. Nonetheless, combustor design can significantly reduce soot emissions through extensive oxidation or lean, near-premixed combustion. For example, lean, premixed prevaporized combustors significantly reduce emissions at high thrust by allowing injected fuel to fully vaporize before ignition, while low temperatures from very lean jet fuel combustion limit the formation of NOx. Alternative fuels can be used alongside improved combustor technologies to reduce soot emissions. However, current policies and low supply promote the blending of alternative fuels at low ratios (∼ 1 %) for all flights, rather than using high ratios (> 30 %) in a few flights which could meaningfully reduce soot emissions. Here, existing technologies for reducing such emissions through combustor and fuel design will be reviewed to identify strategies that eliminate them.\u0000","PeriodicalId":511317,"journal":{"name":"Aerosol Research","volume":"80 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141655325","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":"Performance evaluation of a semivolatile aerosol dichotomous sampler (SADS) for exposure assessment: impact of design issues","authors":"Noredine Rekeb, Benjamin Sutter, E. Belut, E. Géhin, Raymond Olsen","doi":"10.5194/ar-2-183-2024","DOIUrl":"https://doi.org/10.5194/ar-2-183-2024","url":null,"abstract":"Abstract. Aerosols of semivolatile organic compounds (SVOCs) pose significant health risks to workers in various occupational settings. Measuring human exposure to these aerosols requires a separate assessment of the contribution of particles and gases, which is not resolved by existing sampling techniques. Here, we investigate experimentally the performance of a semivolatile aerosol dichotomous sampler (SADS), proposed in previous studies, for sampling monodisperse liquid particles with aerodynamic diameters between 0.15 and 4.5 µm, corresponding to workplace aerosols. The measured sampling performances are compared to their theoretical counterparts computed by computational fluid dynamics. The effects of leakage rate, repeatability of the assembly, imprecision of the actually machined nozzle diameters, and SADS part misalignment are examined. The SADS assembly is found to be easily leaky, but consequences on sampling can be overcome when a prior leak test with a leakage rate below 4 Pa s−1 is passed. Variation of nozzle diameters in the range (−4.5 %, +3.7 %) with respect to nominal values affects marginally (< 3 %) aerosol transmission efficiency, but sampling performance is little reproducible during successive SADS assemblies (CV = 22.1 % for wall losses). Theoretically unpredicted large (40 %–46 %) wall losses are measured for particles larger than 2 µm, located mostly (80 %) on the external walls of the collection nozzle. Assembly repeatability issues and simulations of SADS parts misalignment effect by computational fluid dynamics (CFD) suggest that these undesirable particle deposits are due to the mechanical backlashes of the assembly. Thus, the current design does not guarantee a nozzle misalignment of less than 5 % of the acceleration nozzle diameter, and other important geometric parameters are not further constrained. The promising theoretical sampling performance of the SADS for SVOC aerosols larger than 1 µm thus falls short of expectations due to mechanical design issues that can be improved before possible field use.\u0000","PeriodicalId":511317,"journal":{"name":"Aerosol Research","volume":"36 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141338533","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":"Atmospheric ice-nucleating particles in the eastern Mediterranean and the contribution of mineral and biological aerosol","authors":"M. Tarn, Bethany V Wyld, N. Reicher, Matan Alayof, Daniel Gat, A. Sanchez-Marroquin, S. Sikora, A. Harrison, Y. Rudich, Benjamin J. Murray","doi":"10.5194/ar-2-161-2024","DOIUrl":"https://doi.org/10.5194/ar-2-161-2024","url":null,"abstract":"Abstract. While the atmosphere in the eastern Mediterranean is part of the dust belt, it encounters air masses from Europe, the Mediterranean Sea, and the Sahara and Arabian Desert that bring with them a whole host of potential dust and bioaerosol compositions and concentrations via long-range transport. The consequential changes in the populations of ice-nucleating particles (INPs), aerosols that influence weather and climate by the triggering of freezing in supercooled cloud water droplets, including in the convective cloud systems in the region, are not so well understood beyond the influence of desert dust storms in increasing INP concentrations. Here, we undertook an intensive INP measurement campaign in Israel to monitor changes in concentrations and activity from four major air masses, including the potential for activity from biological INPs. Our findings show that the INP activity in the region is likely dominated by the K-feldspar mineral content, with southwesterly air masses from the Sahara and easterly air masses from the Arabian Desert markedly increasing both aerosol and INP concentrations. Most intriguingly, a handful of air masses that passed over the Nile Delta and the northern Fertile Crescent, regions containing fertile agricultural soils and wetlands, brought high INP concentrations with strong indicators of biological activity. These results suggest that the Fertile Crescent could be a sporadic source of high-temperature biological ice-nucleating activity across the region that could periodically dominate the otherwise K-feldspar-controlled INP environment. We propose that these findings warrant further exploration in future studies in the region, which may be particularly pertinent given the ongoing desertification of the Fertile Crescent that could reveal further sources of dust and fertile soil-based INPs in the eastern Mediterranean region.\u0000","PeriodicalId":511317,"journal":{"name":"Aerosol Research","volume":"64 36","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141346893","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":"Comparison of scanning aerosol lidar and in situ measurements of aerosol physical properties and boundary layer heights","authors":"Hengheng Zhang, Christian Rolf, Ralf Tillmann, Christian Wesolek, F. Wienhold, Thomas Leisner, H. Saathoff","doi":"10.5194/ar-2-135-2024","DOIUrl":"https://doi.org/10.5194/ar-2-135-2024","url":null,"abstract":"Abstract. The spatiotemporal distribution of aerosol particles in the atmosphere has a great impact on radiative transfer, clouds, and air quality. Modern remote sensing methods, as well as airborne in situ measurements by unpiloted aerial vehicles (UAV) or balloons, are suitable tools to improve our understanding of the role of aerosol particles in the atmosphere. To validate the measurement capabilities of three relatively new measurement systems and to bridge the gaps that are often encountered between remote sensing and in situ observation, as well as to investigate aerosol particles in and above the boundary layer, we conducted two measurement campaigns and collected a comprehensive dataset employing a scanning aerosol lidar, a balloon-borne radiosonde with the Compact Optical Backscatter Aerosol Detector (COBALD), an optical particle counter (OPC) on a UAV, and a comprehensive set of ground-based instruments. The extinction coefficients calculated from near-ground-level aerosol size distributions measured in situ are well correlated with those retrieved from lidar measurements, with a slope of 1.037 ± 0.015 and a Pearson correlation coefficient of 0.878, respectively. Vertical profiles measured by an OPC-N3 on a UAV show similar vertical particle distributions and boundary layer heights to lidar measurements. However, the sensor, OPC-N3, shows a larger variability in the aerosol backscatter coefficient measurements, with a Pearson correlation coefficient of only 0.241. In contrast, the COBALD data from a balloon flight are well correlated with lidar-derived backscatter data from the near-ground level up to the stratosphere, with a slope of 1.063 ± 0.016 and a Pearson correlation coefficient of 0.925, respectively. This consistency between lidar and COBALD data reflects the good data quality of both methods and proves that lidar can provide reliable and spatial distributions of aerosol particles with high spatial and temporal resolutions. This study shows that the scanning lidar has the capability to retrieve backscatter coefficients near the ground level (from 25 to 50 m above ground level) when it conducts horizontal measurement, which is not possible for vertically pointing lidar. These near-ground-level retrievals compare well with ground-level in situ measurements. In addition, in situ measurements on the balloon and UAV validated the scanning lidar retrievals within and above the boundary layer. The scanning aerosol lidar allows us to measure aerosol particle distributions and profiles from the ground level to the stratosphere with an accuracy equal to or better than in situ measurements and with a similar spatial resolution.\u0000","PeriodicalId":511317,"journal":{"name":"Aerosol Research","volume":"60 22","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141383636","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":"A cluster-of-functional-groups approach for studying organic enhanced atmospheric cluster formation","authors":"Astrid Nørskov Pedersen, Y. Knattrup, J. Elm","doi":"10.5194/ar-2-123-2024","DOIUrl":"https://doi.org/10.5194/ar-2-123-2024","url":null,"abstract":"Abstract. The role of organic compounds in atmospheric new particle formation is difficult to disentangle due to the myriad of potentially important oxygenated organic molecules (OOMs) present in the atmosphere. Using state-of-the-art quantum chemical methods, we here employ a novel approach, denoted the “cluster-of-functional-groups” approach, for studying the involvement of OOMs in atmospheric cluster formation. Instead of the usual “trial-and-error” approach of testing the ability of experimentally identified OOMs to form stable clusters with other nucleation precursors, we here study which, and how many, intermolecular interactions are required in a given OOM to form stable clusters. In this manner we can reverse engineer the elusive structure of OOM candidates that might be involved in organic enhanced atmospheric cluster formation. We calculated the binding free energies of all combinations of donor and acceptor organic functional groups to investigate which functional groups most preferentially bind with each other and with other nucleation precursors such as sulfuric acid and bases (ammonia, methyl-, dimethyl- and trimethylamine). We find that multiple carboxyl groups lead to substantially more stable clusters compared to all other combinations of functional groups. Employing cluster dynamics simulations, we investigate how a hypothetically OOM composed of multiple carboxyl groups can stabilize sulfuric acid–base clusters and provide recommendations for potential atmospheric multi-carboxylic acid tracer compounds that should be explicitly studied in the future. The presented “cluster-of-functional-groups” approach is generally applicable and can be employed in many other applications, such as ion-induced nucleation and potentially in elucidating the structural patterns in molecules that facilitate ice nucleation.\u0000","PeriodicalId":511317,"journal":{"name":"Aerosol Research","volume":"23 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141266291","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":"Intermediate ions as indicator for local new particle formation","authors":"Santeri Tuovinen, J. Lampilahti, V. Kerminen, M. Kulmala","doi":"10.5194/ar-2-93-2024","DOIUrl":"https://doi.org/10.5194/ar-2-93-2024","url":null,"abstract":"Abstract. Atmospheric aerosol particles have a considerable influence on climate via both aerosol–radiation and aerosol–cloud interactions. A major fraction of global aerosol particles, in terms of their number concentration, is due to atmospheric new particle formation (NPF) that involves both neutral and charged clusters and particles. NPF is the major source of atmospheric intermediate ions, i.e., charged particles with mobility diameters between approx. 2 and 7 nm. We investigate ion concentrations between 1.7 and 3.1 nm at the SMEAR II (Station for Measuring Forest Ecosystem–Atmosphere Relations II) measurement station in Hyytiälä, Finland. Both negative and positive ion number size distributions measured by a Neutral cluster and Air Ion Spectrometer (NAIS) are used. Our aim is to find the best diameter size range of ions for identifying and evaluating the intensity of local intermediate ion formation (LIIF). Intermediate ion formation (IIF) refers to the formation of intermediate ions through NPF, while local means that the growth of such ions from smaller clusters has occurred in close proximity (e.g., within 500 m to 1 km) to the measurement site, i.e., locally. We find that the ions in the mobility diameter size range of 2.0–2.3 nm are the best suited for detection of LIIF. The ion concentrations in this size range indicate the elevated rates of IIF, and the potential distances the growing ions have traveled are smaller than those for larger ions. In addition, in Hyytiälä, the negative ion concentrations are more sensitive to IIF than the positive ion concentrations due to the higher difference in concentrations between periods of IIF and the background. Therefore, we recommend the concentrations of ions with diameters 2.0–2.3 nm as the best choice for identifying and evaluating the intensity of LIIF.\u0000","PeriodicalId":511317,"journal":{"name":"Aerosol Research","volume":"31 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141109781","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":"Determining the ultraviolet radiation dose experienced by aerosols using ultraviolet-sensitive dyes","authors":"Q. Fu, F. Kruis","doi":"10.5194/ar-2-77-2024","DOIUrl":"https://doi.org/10.5194/ar-2-77-2024","url":null,"abstract":"Abstract. ​​​​​​​The application of ultraviolet (UV)-light-based air disinfection methods holds promise but also presents several challenges. Among these, the quantitative determination of the required UV radiation dose for aerosols is particularly significant. This study explores the possibility of determining the UV dose experienced by aerosols without the use of virus-containing aerosols, circumventing associated laboratory safety issues. To achieve this, we developed a model system comprised of UV-sensitive dyes dissolved in di-ethyl-hexyl-sebacate (DEHS), which facilitates the generation of non-evaporating and UV-degradable aerosols. For the selection of UV-sensitive dyes, 20 dyes were tested, and 2 of them were selected as being the most suitable, according to several selection criteria. Dye-laden aerosol droplets were generated using a commercial aerosol generator and subsequently exposed to UV-C radiation in a laboratory-built UV irradiation chamber. We designed a low-pressure impactor to collect the aerosols pre- and post-UV exposure. Dye degradation, as a result of UV light exposure, was then analyzed by assessing the concentration changes in the collected dye solutions using a UV-visible spectrophotometer. Our findings revealed that a UV dose of 245 mW s cm−2 resulted in a 10 % degradation, while a lower dose of 21.6 mW s cm−2 produced a 5 % degradation. In conclusion, our study demonstrates the feasibility of using aerosol droplets containing UV-sensitive dyes to determine the UV radiation dose experienced by an aerosol.\u0000","PeriodicalId":511317,"journal":{"name":"Aerosol Research","volume":"36 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140966319","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":"A multi-instrumental approach for calibrating real-time mass spectrometers using high-performance liquid chromatography and positive matrix factorization","authors":"Melinda (Mindy) Schueneman, D. Day, Dongwook Kim, P. Campuzano‐Jost, Seonsik Yun, Marla P. DeVault, Anna C. Ziola, Paul J. Ziemann, Jose L. Jimenez","doi":"10.5194/ar-2-59-2024","DOIUrl":"https://doi.org/10.5194/ar-2-59-2024","url":null,"abstract":"Abstract. Obtaining quantitative information for molecular species present in aerosols from real-time mass spectrometers such as an extractive electrospray time-of-flight mass spectrometer (EESI) and an aerosol mass spectrometer (AMS) can be challenging. Typically, molecular species are calibrated directly through the use of pure standards. However, in some cases (e.g., secondary organic aerosol (SOA) formed from volatile organic compounds (VOCs)), direct calibrations are impossible, as many SOA species can either not be purchased as pure standards or have ambiguous molecular identities. In some cases, bulk OA sensitivities are used to estimate molecular sensitivities. This approach is not sufficient for EESI, which measures molecular components of OA, because different species can have sensitivities that vary by a factor of more than 30. Here, we introduce a method to obtain EESI calibration factors when standards are not available, and we provide a thorough analysis of the feasibility, performance, and limitations of this new technique. In this method, complex aerosol mixtures were separated with high-performance liquid chromatography (HPLC) followed by aerosol formation via atomization. The separated aerosols were then measured by an EESI and an AMS, which allowed us to obtain sensitivities for some species present in standard and SOA mixtures. Pure compounds were used to test the method and characterize its uncertainties, and obtained sensitivities were consistent within ±20 % when comparing direct calibrations vs. HPLC calibrations for a pure standard and within a factor of 2 for a standard mixture. In some cases, species were not completely resolved by chromatography, and positive matrix factorization (PMF) of AMS data enabled further separation. This method should be applicable to other real-time MS techniques. Improvements in chromatography are possible that would allow better separation in complex mixtures.\u0000","PeriodicalId":511317,"journal":{"name":"Aerosol Research","volume":" 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140998379","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}