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We present the continuous data record of atmospheric CO2 isotopes measured by laser absorption spectroscopy for an almost four year period at the High Altitude Research Station Jungfraujoch (3580ma.s.l.), Switzerland. The mean annual cycles derived from data of December 2008 to September 2012 exhibit peak-to-peak amplitudes of 11.0 μmolmol-1 for CO2, 0.60‰ for δ13C and 0.81‰ for δ18O. The high temporal resolution of the measurements also allow us to capture variations on hourly and diurnal timescales. For CO2 the mean diurnal peak-to-peak amplitude is about 1 μmolmol-1 in spring, autumn and winter and about 2 μmolmol-1 in summer. The mean diurnal variability in the isotope ratios is largest during the summer months too, with an amplitude of about 0.1‰ both in the δ13C and δ18O, and a smaller or no discernible diurnal cycle during the other seasons. The day-to-day variability, however, is much larger and depends on the origin of the air masses arriving at Jungfraujoch. Backward Lagrangian particle dispersion model simulations revealed a close link between air composition and prevailing transport regimes and could be used to explain part of the observed variability in terms of transport history and influence region. A footprint clustering showed significantly different wintertime CO2, δ13C and δ18O values depending on the origin and surface residence times of the air masses. Several major updates on the instrument and the calibration procedures were performed in order to further improve the data quality. We describe the new measurement and calibration setup in detail and demonstrate the enhanced performance of the analyzer. A measurement precision of about 0.02‰ for both isotope ratios has been obtained for an averaging time of 10 min, while the accuracy was estimated to be 0.1 ‰, including the uncertainty of the calibration gases. [ABSTRACT FROM AUTHOR]

We present the continuous data record of atmospheric CO2 isotopes measured by laser absorption spectroscopy for an almost four year period at the High Altitude Research Station Jungfraujoch (3580 m a.s.l.), Switzerland. The mean annual cycles derived from data of December 2008 to September 2012 exhibit peak-to-peak amplitudes of 11.0 μmol mol-1 for CO2, 0.60‰ for δ13C and 0.81‰ for δ18O. The high temporal resolution of the measurements also allow to capture variations on hourly and diurnal time scales. For CO2 the mean diurnal peak-to-peak amplitude is about 1 μmolmol-1 in spring, autumn and winter and about 2 μmolmol-1 in summer. The mean diurnal variability in the isotope ratios is largest during the summer months too, with an amplitude of about 0.1‰ both in the δ13C and δ18O, and a smaller or no discernible diurnal cycle during the other seasons. The day-to-day variability, however, is much larger and depends on the origin of the air masses arriving at Jungfraujoch. Backward Lagrangian particle dispersion model simulations revealed a close link between air composition and prevailing transport regimes and could be used to explain part of the observed variability in terms of transport history and influence region. A footprint clustering showed significantly different wintertime CO2, δ13C and δ18O values depending on the origin and surface residence times of the air masses. Based on the experiences gained from our measurements, several major updates on the instrument and the calibration procedures were performed in order to further improve the data quality. We describe the new measurement and calibration setup in detail and demonstrate the enhanced performance of the analyser. A precision of about 0.02‰ for both isotope ratios has been obtained for an averaging time of 10 min. [ABSTRACT FROM AUTHOR]

The article focuses on an approach for atmospheric ice nucleator (IC) measurement which is based on filter collections. It notes that such method utilizes quartz filters used in particulate matter ≤ 10 μm (PM10) monitoring in 24 hours. It shows that the number concentrations of IN which are active at -8, -10, and -12 degrees Celsius were on average 3.3, 10.7, and 17.2 meter (m)-3.

The article presents a study on quantifying ice nucleators (IN) which is active in warm temperatures in the Swiss Alps, Switzerland. It proposes an improved filter method using quartz filters in 24 PM10 monitoring. The study finds several fold larger numbers of IN active in air masses which is influenced by atmospheric boundary layer air. Also, the method can be used in reconstructing time series of IN number concentrations.

A Kalman-filter based inverse emission estimation method for long-lived trace gases is presented for use in conjunction with a Lagrangian particle dispersion model like FLEXPART. The sequential nature of the approach allows tracing slow seasonal and interannual changes rather than estimating a single period-mean emission field. Other important features include the estimation of a slowly varying concentration background at each measurement station, the possibility to constrain the solution to non-negative emissions, the quantification of uncertainties, the consideration of temporal correlations in the residuals, and the applicability to potentially large inversion problems. The method is first demonstrated for a set of synthetic observations created from a prescribed emission field with different levels of (correlated) noise, which closely mimics true observations. It is then applied to real observations of the three halocarbons HFC-125, HFC-152a and HCFC-141b at the remote research stations Jungfraujoch and Mace Head for the quantification of emissions in Western European countries from 2006 to 2010. Estimated HFC-125 emissions are mostly consistent with national totals reported to the Kyoto protocol and show a generally increasing trend over the considered period. Results for HFC-152a are much more variable with estimated emissions being both higher and lower in different countries. The highest emissions of the order of 1000Mg yr-1 are estimated for Italy which so far does not report HFC-152a emissions. Emissions of HCFC-141b show a continuing strong decrease as expected due to its ban under the Montreal Protocol. Emissions from France, however, were still rather large (near 1000Mg yr-1) in the years 2006 and 2007 but strongly declined thereafter. [ABSTRACT FROM AUTHOR]

The source contributions to carbonaceous PM 2.5 aerosol were investigated at a European background site at the edge of the Po Valley, in Northern Italy, during the period January-December 2007. Carbonaceous aerosol was described as the sum of 8 source components: primary (1) and secondary (2) biomass burning organic carbon, biomass burning elemental carbon (3), primary (4) and secondary (5) fossil organic carbon, fossil fuel burning elemental carbon (6), primary (7) and secondary (8) biogenic organic carbon. The mass concentration of each component was quantified using a set of macro tracers (organic carbon OC, elemental carbon EC, and levoglucosan), micro tracers (arabitol and mannitol), and 14C measurements. This was the first time that 14C measurements covered a full annual cycle with daily resolution. This set of 6 tracers, together with assumed uncertainty ranges of the ratios of OC-to-EC, and the reference fraction of modern carbon in the 8 source categories, provides strong constraints to the source contributions to carbonaceous aerosol. The uncertainty of contributions was assessed with a Quasi-Monte Carlo (QMC) method accounting for the variability of OC and EC emission factors, the uncertainty of reference fractions of modern carbon, and the measurement uncertainty. During winter, biomass burning composed 64% (±15%) of the total carbon (TC) concentration, while in summer secondary biogenic OC accounted for 50% (±16%) of TC. The contribution of primary biogenic aerosol particles was negligible during the entire year. Moreover, aerosol associated with fossil sources represented 27% (±16%) and 41% (±26%) of TC in winter and summer, respectively. The contribution of secondary organic aerosol (SOA) to the organic mass (OM) was significant during the entire year. SOA accounted for 30% (±16%) and 85% (±12%) of OM during winter and summer, respectively. While the summer SOA was dominated by biogenic sources, winter SOA was mainly due to biomass burning and fossil sources. This indicates that the oxidation of semi-volatile and intermediate volatility organic compounds co-emitted with primary organics is a significant source of SOA, as suggested by recent model results and Aerosol Mass Spectrometer measurements. Comparison with previous global model simulations, indicates a strong underestimate of wintertime primary aerosol emissions in this region. The comparison of source apportionment results in different urban and rural areas showed that the sampling site was mainly affected by local aerosol sources during winter and regional air masses from the nearby Po Valley in summer. This observation was further confirmed by back-trajectory analysis applying the Potential Source Contribution Function method to identify potential source regions. [ABSTRACT FROM AUTHOR]

National and European legislation over the past 20 years, and the modernisation or removal of industrial sources, have significantly reduced European ozone precursor emissions. This study quantifies observed and modelled European ozone annual and seasonal linear trends from 158 harmonised rural background monitoring stations over a constant time period of a decade (1996-2005). Mean ozone concentrations are investigated, in addition to the ozone 5th percentiles as a measure of the baseline or background conditions, and the 95th percentiles that are representative of the peak concentration levels. This study aims to characterise and quantify surface European ozone concentrations and trends and assess the impact of the changing anthropogenic emission tracers on the observed and modelled trends. Significant (p < 0.1) positive annual trends in ozone mean, 5th and 95th percentiles are observed at 54 %, 52% and 45% of sites respectively (85 sites, 82 sites and 71 sites). Spatially, sites in Central and Northwestern Europe tend to display positive annual ozone trends in mean, 5th and 95th percentiles. Significant negative annual trends in ozone mean 5th and 95th percentiles are observed at 11 %, 12% and 12% of sites respectively (18 sites, 19 sites and 19 sites) which tend to be located in the eastern and south-western extremities of Europe. European-averaged annual trends have been calculated from the 158 sites in this study. Overall there is a net positive annual trend in observed ozone mean (0.16 ± 0.02 ppbv yr-1 (2σ error)), 5th (0.13 ± 0.02 ppbv yr-1) and 95th (0.16 ± 0.03 ppbv yr-1) percentiles, representative of positive trends in mean, baseline and peak ozone. Assessing the sensitivity of the derived overall trends to the constituent years shows that the European heatwave year of 2003 has significant positive influence and 1998 the converse effect; demonstrating the masking effect of inter-annual variability on decadal based ozone trends. The European scale 3-D CTM CHIMERE was used to simulate hourly O3 concentrations for the period 1996-2005. Comparisons between the 158 observed ozone trends to those equivalent sites extracted from regional simulations by CHIMERE better match the observed increasing annual ozone (predominantly in Central and Northwestern Europe) for 5th percentiles, than for mean or 95th ozone percentiles. The European-averaged annual ozone trend in CHIMERE 5th percentiles (0.13 ± 0.01 ppbv yr-1) matches the corresponding observed trend extremely well, but displays a negative trend for the 95th percentile (-0.03 ± 0.02 ppbv yr-1) where a positive ozone trend is observed. Inspection of the EU-averaged monthly means of ozone shows that the CHIMERE model is overestimating the summer month O3 levels. In comparison to trends in EMEP emissions inventories, with the exception of Austria-Hungary, we find anthropogenic NOx and VOC reductions do not appear to have a substantial effect on observed annual mean O3 trends in the rest of Europe. [ABSTRACT FROM AUTHOR]

The April-May 2010 volcanic eruptions of Eyjafjallajökull, Iceland caused significant economic and social disruption in Europe whilst state of the art measurements and ash dispersion forecasts were heavily criticized by the aviation industry. Here we demonstrate for the first time that dramatic improvements can be made in quantitative predictions of the fate of volcanic ash emissions, by using an inversion scheme that couples a priori source information and the output of a Lagrangian dispersion model with satellite data to estimate the volcanic ash source strength as a function of altitude and time. From the inversion, we obtain a total fine ash emission of the eruption of 8.3 ± 4.2 Tg for particles in the size range of 2.8--28 µm diameter and extrapolate this to a total ash emission of 11.9 ± 5.9 Tg for the size range of 0.25-250 µm. We evaluate the results of our a posteriori model using independent ground-based, airborne and space-borne measurements both in case studies and statistically. Subsequently, we estimate the area over Europe affected by volcanic ash above certain concentration thresholds relevant for the aviation industry. We find that during three episodes in April and May, volcanic ash concentrations at some altitude in the atmosphere exceeded the limits for the "normal" flying zone in up to 14% (6-16%), 2% (1-3%) and 7% (4-11%), respectively, of the European area. For a limit of 2 mg m-3 only two episodes with fractions of 1.5% (0.2-2.8%) and 0.9% (0.1-1.6%) occurred, while the current "no-fly" zone criterion of 4 mg m-3 was rarely exceeded. Our results have important ramifications for determining air space closures and for real-time quantitative estimations of ash concentrations. Furthermore, the general nature of our method yields better constraints on the distribution and fate of volcanic ash in the Earth system. [ABSTRACT FROM AUTHOR]

The article discusses a study on the use of local regression for robust extraction of baseline signal of atmospheric trace species. The study uses the bootstrap technique to calculate the uncertainty in the resulting baseline curve in the atmospheric composition. It also demonstrate feasibility and usefulness of the proposed approach through applying carbon monoxide (CO) measured from 1996 to 2009.

The atmospheric layer closest to the ground is strongly influenced by variable surface fluxes (emissions, surface deposition) and can therefore be very heterogeneous. In order to perform air quality measurements that are representative of a larger domain or a certain degree of pollution, observatories are placed away from population centres or within areas of specific population density. Sites are often categorised based on subjective criteria that are not uniformly applied within different administrative domains. A novel approach for the assessment of parameters reflecting site representativeness is presented here, taking emissions, deposition and transport towards 34 sites covering Western and Central Europe into account. These parameters are directly inter-comparable among the sites and can be used to select sites that are, on average, more or less suitable for data assimilation and comparison with satellite and model data. Advection towards these sites was simulated by backward Lagrangian Particle Dispersion Modelling (LPDM) to determine the sites' annual catchment areas for the year 2005 and advection times of 12, 24 and 48 h. Only variations caused by emissions and transport during these periods were considered assuming that these dominate the short-term variability of most but especially short lived trace gases. The parameters of representativeness derived were compared between sites and a novel, uniform and observation-independent categorisation of the sites based on a clustering approach was established. Six groups of European background sites were identified ranging from very remote coastal to polluted rural sites. These six categories explained 50 to 80% of the inter-site variability of median mixing ratios and their standard deviation for NO2 and O3, while differences between group means of the longer lived trace gas CO were insignificant. The derived annual catchment areas strongly depended on the applied LPDM and input wind fields, the catchment settings and the year of analysis. Nevertheless, the parameters of representativeness showed considerably less variability than the catchment geometry, supporting the robustness of the derived station categorisation. [ABSTRACT FROM AUTHOR]

The tropics strongly influence the global atmospheric chemistry budget. However, continuous in-situ observations of trace gases are rare especially in equatorial Africa. The WMO Global Atmosphere Watch (GAW) programme aimed to close this gap with the installation of the Mt. Kenya (MKN) baseline station. Here, the first continuous measurements of carbon monoxide (CO) and ozone (O3) at this site covering the period June 2002 to June 2006 are presented. The representativeness of the site was investigated by means of statistical data analysis, air mass trajectory clustering, interpretation of biomass burning variability and evaluation of O3-CO relationships. Because of its location in eastern equatorial Africa, the site was rarely directly influenced by biomass burning emissions, making it suitable for background observations. Located at 3678m above sea level the night-time (21:00-04:00 UTC) measurements of CO and O3 were in general representative of the free troposphere, while day-time measurements were influenced by atmospheric boundary layer air. Increased night-time concentrations were observed in 25% of all nights and associated with residual layers of increased CO and water vapour in the free troposphere. Six representative flow regimes towards Mt. Kenya were determined: eastern Africa (21% of the time), Arabian Peninsula and Pakistan (16%), northern Africa free tropospheric (6%), northern Indian Ocean and India (17%), south-eastern Africa (18%) and southern India Ocean (21%) flow regimes. The seasonal alternation of these flow regimes was determined by the monsoon circulation and caused a distinct semi-annual cycle of CO with maxima during February (primary) and August (secondary, annually variable) and with minima in April (primary) and November (secondary, annually variable). O3 showed a weaker annual cycle with a minimum in November and a broad sum mer maximum. Inter-annual variations were explained with differences in southern African biomass burning and transport towards MKN. Although biomass burning had little direct influence on the measurements at MKN it introduces inter-annual variability in the background concentrations of the southern hemisphere that subsequently reaches Kenya. The measurements atMKN were representative of air masses with little photochemical activity as indicated by weak O3-CO correlations, underlining the baseline character of the site. Inter-comparison of O3 at MKN with sounding data from Nairobi revealed a positive offset of the sounding data, most likely due to additional photochemical production of O3 in the Nairobi city plume. Future extensions of the measurement programme will provide better understanding of the atmospheric chemistry of this globally important region. [ABSTRACT FROM AUTHOR]

The tropics strongly influence the global atmospheric chemistry budget. However, continuous in-situ observations of trace gases are rare especially in equatorial Africa. The WMO Global Atmosphere Watch programme aimed to close this gap with the installation of the Mt. Kenya baseline station. Here, the first continuous measurements of carbon monoxide (CO) and ozone O3 at this site are presented. The representativeness of the site was investigated by means of statistical data analysis, air mass trajectory clustering, interpretation of biomass burning variability and evaluation of O3-CO relationships. Despite its location in equatorial Africa the site was rarely directly influenced by biomass burning emissions, making it suitable for background observations. Located at 3678 m above sea level the night-time (21:00-04:00 UTC) measurements were in general representative of the free troposphere, while day-time measurements were influenced by atmospheric boundary layer air. Six representative flow regimes towards Mt. Kenya were determined: eastern Africa (21% of the time), Arabian Peninsula and Pakistan (16%), northern Africa free tropospheric (6%), northern Indian Ocean and India (17%), south-eastern Africa (18%) and southern India Ocean (21%). The seasonal alternation of these flow regimes was determined by the monsoon circulation and caused a distinct semi-annual cycle of CO with maxima during February and August and with minima in April and less pronounced in November. O3 showed a weaker annual cycle with a minimum in November and a broad summer maximum. Inter-annual variations were explained with variations in southern African biomass burning and in transport patterns. The measurements at MKN were representative of air masses with little photochemical activity as indicated by weak O3-CO correlations, underlining the baseline character of the site. Future extensions of the measurement programme will provide better understanding of the atmospheric chemistry of this globally important region. [ABSTRACT FROM AUTHOR]

Although a consistent pattern of ipsilateral movement coupling between cervical spine rotation and lateral flexion has been widely described, variability in these movement patterns has not been reported. In 30 asymptomatic subjects, the ranges of primary and coupled movements were determined in the neutral posture, and in the extremes of cervical spine protraction and retraction. All measurements were performed using the SpinT three-dimensional goniometer for which excellent intra-tester reliability was demonstrated for both primary (ICC(3,1) 0.93-0.98) and coupled (ICC(3,1) 0.76-0.98) movements. The ranges of primary and coupled movements changed significantly when movement was initiated from the end-range postures (P < 0.001). In the neutral posture, approximately 70% of subjects demonstrated an ipsilateral pattern of coupled movement. During cervical rotation, the dominant coupling pattern seen in neutral was no longer retained in retraction, while the protracted posture had a greater influence on the coupled movements accompanying primary lateral flexion. The concept of a stereotypical pattern of cervical spine movement coupling is not supported by these results. The posture in which movements are initiated appears to have a significant influence on the three-dimensional kinematics of the cervical spine. [ABSTRACT FROM AUTHOR]

HFC-23 is a potent greenhouse gas, predominantly emitted as an undesired by-product during the synthesis and processing of HCFC-22 (ref.  1 ). Previously, the Clean Development Mechanism and national efforts called for the implementation of abatement technology for reducing HFC-23 emissions 2,3 . Nevertheless, between 2015 and 2019, a divergence was found between the global emissions derived from atmospheric observations and those expected from reported abatement 1,2 . Primarily, this points to insufficient implementation of abatement strategies 2,4 , calling for independent verification of the emissions at the individual chemical facility level. Here we use regional atmospheric observations and a new, deliberately released tracer to quantify the HFC-23 emissions from an HCFC-22 and fluoropolymer production facility, which is equipped with waste gas destruction technology. We find that our inferred HFC-23/HCFC-22 emission factor of 0.19% (0.13-0.24%) broadly fits within the emission factor considered practicable for abatement projects 5,6 . Extrapolation to global HCFC-22 production underscores that the operation of appropriate destruction technology has the potential to reduce global HFC-23 emissions by at least 84% (69-100%) (14 (12-16) Gg yr -1 ). This reduction is equivalent to 17% CO 2 emissions from aviation in 2019 (ref.  7 ). We also demonstrate co-destruction of PFC-318, another by-product and greenhouse gas. Our findings show the importance of the 2016 Kigali Amendment to the Montreal Protocol, which obligates parties to destroy HFC-23 emissions from facilities manufacturing hydrochlorofluorocarbons and hydrofluorocarbons "to the extent practicable" from 2020 onwards 8 ., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

Forecasting concentrations of PM 2.5 is important due to its known impacts on public health and environment. However, PM 2.5 concentrations can vary significantly over short distances and time, which can be influenced by local emissions and short-term weather patterns. This spatiotemporal variability makes accurate PM 2.5 forecasting an inherently complex and challenging task. This study presented novel methodologies for short-term PM 2.5 concentration forecast by combining the atmospheric chemistry transport model Community Multiscale Air Quality Modeling System (CMAQ) with data-driven machine learning methods, namely long short-term memory (LSTM) and random forest (RF) models. The combined model system forecast PM 2.5 with 1 h, 1km × 1 km spatiotemporal resolution. The LSTM system forecast time-dependent PM 2.5 concentrations at observation sites with a maximum root mean square error (RMSE) of 3.66 μg/m 3 for 1-hr forecast and 23.75 μg/m 3 for 72-hr forecast, leveraging results obtained from the atmospheric transport model with RMSE of 45.81 μg/m 3 . Wavelet transform in the LSTM system allowed learning and prediction of PM 2.5 concentrations at different frequencies, capturing temporal variability of PM 2.5 at various time scales. The RF model predicted distributions of PM 2.5 concentrations by learning LSTM results and integrating crucial features such as CMAQ results, meteorological and topographical information. The feature significance of CMAQ results was the highest among the input features in RF models. Overall, the hybrid model could help with managing and mitigating the adverse effects of air pollution by enabling informed decision-making at the individual, community and policy levels., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Risk assessment of pesticide impacts on remote ecosystems makes use of model-estimated degradation in air. Recent studies suggest these degradation rates to be overestimated, questioning current pesticide regulation. Here, we investigated the concentrations of 76 pesticides in Europe at 29 rural, coastal, mountain, and polar sites during the agricultural application season. Overall, 58 pesticides were observed in the European atmosphere. Low spatial variation of 7 pesticides suggests continental-scale atmospheric dispersal. Based on concentrations in free tropospheric air and at Arctic sites, 22 pesticides were identified to be prone to long-range atmospheric transport, which included 15 substances approved for agricultural use in Europe and 7 banned ones. Comparison between concentrations at remote sites and those found at pesticide source areas suggests long atmospheric lifetimes of atrazine, cyprodinil, spiroxamine, tebuconazole, terbuthylazine, and thiacloprid. In general, our findings suggest that atmospheric transport and persistence of pesticides have been underestimated and that their risk assessment needs to be improved.

For the past few years, short-lived unsaturated halocarbons have been marketed as environmentally friendly replacements for long-lived halogenated greenhouse gases and ozone-depleting substances. The phase-in of unsaturated halocarbons for various applications, such as refrigeration and foam blowing, can be tracked by their emergence and increase in the atmosphere. We present the first atmospheric measurements of the hydrofluoroolefin (HFO) HFO-1336mzz( Z ) (( Z )-1,1,1,4,4,4-hexafluoro-2-butene, cis -CF 3 CH═CHCF 3 ), a newly used unsaturated hydrofluorocarbon. HFO-1336mzz( Z ) has been detected in >90% of all measurements since 2018 during multi-month campaigns at three Swiss and one Dutch location. Since 2019, it is found in ∼30% of all measurements that run continuously at the Swiss high-altitude Jungfraujoch station. During pollution events, mole fractions of up to ∼10 ppt were observed. Based on our measurements, Swiss and Dutch emissions were estimated at 2-7 Mg yr -1 (2019-2021) and 30 Mg yr -1 (2022), respectively. Modeled spatial emission distributions only partly conform to population density in both countries. Monitoring the presence of new unsaturated halocarbons in the atmosphere is crucial since long-term effects of their degradation products are still debated. Furthermore, the production of HFOs involves climate-active substances, which may leak to the atmosphere─in the case of HFO-1336mzz( Z ), for example, the ozone-depleting CFC-113a (CF 3 CCl 3 ).

With growing molecular evidence for correlations between spatial arrangement of blood vasculature and fundamental immunological functions, carried out in distinct compartments of the subdivided lymph node, there is an urgent need for three-dimensional models that can link these aspects. We reconstructed such models at a 1.84 µm resolution by the means of X-ray phase-contrast imaging with a 2D Talbot array in a short time without any staining. In addition reconstructions are verified in immunohistochemistry staining as well as in ultrastructural analyses. While conventional illustrations of mammalian lymph nodes depict the hilus as a definite point of blood and lymphatic vessel entry and exit, our method revealed that multiple branches enter and emerge from an area that extends up to one third of the organ's surface. This could be a prerequisite for the drastic and location-dependent remodeling of vascularization, which is necessary for lymph node expansion during inflammation. Contrary to corrosion cast studies we identified B-cell follicles exhibiting a two times denser capillary network than the deep cortical units of the T-cell zone. In addition to our observation of high endothelial venules spatially surrounding the follicles, this suggests a direct connection between morphology and B-cell homing. Our findings will deepen the understanding of functional lymph node composition and lymphocyte migration on a fundamental basis., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Schwarzenberg, Schütz, Hammel, Riedel, Bartl, Bordbari, Frank, Walkenfort, Busse, Herzen, Lohr, Wülfing and Henne.)

Global emissions of the ozone-depleting gas HCFC-141b (1,1-dichloro-1-fluoroethane, CH 3 CCl 2 F) derived from measurements of atmospheric mole fractions increased between 2017 and 2021 despite a fall in reported production and consumption of HCFC-141b for dispersive uses. HCFC-141b is a controlled substance under the Montreal Protocol, and its phase-out is currently underway, after a peak in reported consumption and production in developing (Article 5) countries in 2013. If reported production and consumption are correct, our study suggests that the 2017-2021 rise is due to an increase in emissions from the bank when appliances containing HCFC-141b reach the end of their life, or from production of HCFC-141b not reported for dispersive uses. Regional emissions have been estimated between 2017-2020 for all regions where measurements have sufficient sensitivity to emissions. This includes the regions of northwestern Europe, east Asia, the United States and Australia, where emissions decreased by a total of 2.3 ± 4.6 Ggyr -1 , compared to a mean global increase of 3.0 ± 1.2 Ggyr -1 over the same period. Collectively these regions only account for around 30% of global emissions in 2020. We are not able to pinpoint the source regions or specific activities responsible for the recent global emission rise., Competing Interests: Competing interests. The contact author has declared that none of the authors has any competing interests.

Anthropogenic nitrogen inputs cause major negative environmental impacts, including emissions of the important greenhouse gas N 2 O. Despite their importance, shifts in terrestrial N loss pathways driven by global change are highly uncertain. Here we present a coupled soil-atmosphere isotope model (IsoTONE) to quantify terrestrial N losses and N 2 O emission factors from 1850-2020. We find that N inputs from atmospheric deposition caused 51% of anthropogenic N 2 O emissions from soils in 2020. The mean effective global emission factor for N 2 O was 4.3 ± 0.3% in 2020 (weighted by N inputs), much higher than the surface area-weighted mean (1.1 ± 0.1%). Climate change and spatial redistribution of fertilisation N inputs have driven an increase in global emission factor over the past century, which accounts for 18% of the anthropogenic soil flux in 2020. Predicted increases in fertilisation in emerging economies will accelerate N 2 O-driven climate warming in coming decades, unless targeted mitigation measures are introduced., (© 2022. The Author(s).)

Lagrangian particle dispersion models (LPDMs) are frequently used for regional-scale inversions of greenhouse gas emissions. However, the turbulence parameterizations used in these models were developed for coarse resolution grids, hence, when moving to the kilometre-scale the validity of these descriptions should be questioned. Here, we analyze the influence of the turbulence parameterization employed in the LPDM FLEXPART-COSMO model. Comparisons of the turbulence kinetic energy between the turbulence schemes of FLEXPART-COSMO and the underlying Eulerian model COSMO suggest that the dispersion in FLEXPART-COSMO suffers from a double-counting of turbulent elements when run at a high resolution of 1 × 1 km 2 . Such turbulent elements are represented in both COSMO, by the resolved grid-scale winds, and FLEXPART, by its stochastic parameterizations. Therefore, we developed a new parametrization for the variations of the winds and the Lagrangian time scales in FLEXPART in order to harmonize the amount of turbulence present in both models. In a case study for a power plant plume, the new scheme results in improved plume representation when compared with in situ flight observations and with a tracer transported in COSMO. Further in-depth validation of the LPDM against methane observations at a tall tower site in Switzerland shows that the model's ability to predict the observed tracer variability and concentration at different heights above ground is considerably enhanced using the updated turbulence description. The high-resolution simulations result in a more realistic and pronounced diurnal cycle of the tracer concentration peaks and overall improved correlation with observations when compared to previously used coarser resolution simulations (at 7 km × 7 km). Our results indicate that the stochastic turbulence schemes of LPDMs, developed in the past for coarse resolution models, should be revisited to include a resolution dependency and resolve only the part of the turbulence spectrum that is a subgrid process at each different mesh size. Although our new scheme is specific to COSMO simulations at 1 × 1 km 2 resolution, the methodology for deriving the scheme can easily be applied to different resolutions and other regional models., Supplementary Information: The online version contains supplementary material available at 10.1007/s10546-022-00728-3., Competing Interests: Conflict of interestThe authors declare that they have no conflict of interest., (© The Author(s) 2022.)

Background: Male androgenetic alopecia (AGA) has been implicated as a putative risk factor in severe COVID-19 based on high incidences of advanced AGA in male hospitalized COVID-19 patients. Research further suggests that androgen signalling, which plays a central role in AGA aetiology, promotes SARS-CoV-2 infection and is associated with severe COVID-19 symptoms in men., Objectives: We aimed to systematically investigate a potential association between AGA and COVID-19 both on an epidemiological and a genetic level in a large single-population cohort., Methods: We performed regression, genetic correlation and polygenic risk score (PRS) analyses using data from the UK Biobank and published GWAS data on AGA and COVID-19., Results: Our analyses did not reveal any significant epidemiological or genome-wide genetic association between AGA and severe COVID-19. Pathway-based PRS analyses however revealed a significant association in specific pathways, namely vitamin metabolism, natural killer cell-mediated cytotoxicity, WNT signalling and aryl hydrocarbon receptor signalling., Limitations: We restricted our analyses to the white British population and used self-reported AGA status. Sample size may be a limitation in our regression and PRS analyses., Conclusions: Our data yield no evidence for an epidemiological association between AGA and COVID-19 but suggest that a shared genetic basis for both traits exists in specific pathways., Competing Interests: The authors declare no conflict of interests., (© 2021 The Authors. Skin Health and Disease published by John Wiley & Sons Ltd on behalf of British Association of Dermatologists.)

Recently, we found many immune cells including antigen presenting cells neurally hard wired in the T-cell zone of most lymphoid organs like amongst others, lymph nodes in rats, mice and humans. Single immune cells were reached by single neurites and enclosed with a dense neural meshwork. As it is well known that axons are always accompanied by glial cells, we were able to identify Schwann cells in the hilum, medullary and capsule region, like expected. Unexpected was the result, that we found oligodendrocyte-like cells in these regions, myelinating more than one axon. Likewise important was the finding, that one of the standard glial markers used, a polyclonal GFAP antibody equally bound to desmin and therefore marked nearly all stromal cells in cortical, paracortical and medullary cord regions. More detailed analysis showed that these results also appeared in many other non-lymphoid organs. Therefore, polyclonal GFAP antibodies are only conditionally usable for immunohistochemical analysis in peripheral tissues outside the central nervous system. It remains to be elucidated, if the binding of the GFAP antibody to desmin has its reason in a special desmin variant that can give stromal cells glial character.

Global and regional atmospheric measurements and modeling can play key roles in discovering and quantifying unexpected nascent emissions of environmentally important substances. We focus here on three hydrochlorofluorocarbons (HCFCs) that are restricted by the Montreal Protocol because of their roles in stratospheric ozone depletion. Based on measurements of archived air samples and on in situ measurements at stations of the Advanced Global Atmospheric Gases Experiment (AGAGE) network, we report global abundances, trends, and regional enhancements for HCFC-132b ([Formula: see text]), which is newly discovered in the atmosphere, and updated results for HCFC-133a ([Formula: see text]) and HCFC-31 ([Formula: see text]ClF). No purposeful end-use is known for any of these compounds. We find that HCFC-132b appeared in the atmosphere 20 y ago and that its global emissions increased to 1.1 Gg⋅y -1 by 2019. Regional top-down emission estimates for East Asia, based on high-frequency measurements for 2016-2019, account for ∼95% of the global HCFC-132b emissions and for ∼80% of the global HCFC-133a emissions of 2.3 Gg⋅y -1 during this period. Global emissions of HCFC-31 for the same period are 0.71 Gg⋅y -1 Small European emissions of HCFC-132b and HCFC-133a, found in southeastern France, ceased in early 2017 when a fluorocarbon production facility in that area closed. Although unreported emissive end-uses cannot be ruled out, all three compounds are most likely emitted as intermediate by-products in chemical production pathways. Identification of harmful emissions to the atmosphere at an early stage can guide the effective development of global and regional environmental policy., Competing Interests: The authors declare no competing interest.

Emissions of ozone-depleting substances, including trichlorofluoromethane (CFC-11), have decreased since the mid-1980s in response to the Montreal Protocol 1,2 . In recent years, an unexpected increase in CFC-11 emissions beginning in 2013 has been reported, with much of the global rise attributed to emissions from eastern China 3,4 . Here we use high-frequency atmospheric mole fraction observations from Gosan, South Korea and Hateruma, Japan, together with atmospheric chemical transport-model simulations, to investigate regional CFC-11 emissions from eastern China. We find that CFC-11 emissions returned to pre-2013 levels in 2019 (5.0 ± 1.0 gigagrams per year in 2019, compared to 7.2 ± 1.5 gigagrams per year for 2008-2012, ±1 standard deviation), decreasing by 10 ± 3 gigagrams per year since 2014-2017. Furthermore, we find that in this region, carbon tetrachloride (CCl 4 ) and dichlorodifluoromethane (CFC-12) emissions-potentially associated with CFC-11 production-were higher than expected after 2013 and then declined one to two years before the CFC-11 emissions reduction. This suggests that CFC-11 production occurred in eastern China after the mandated global phase-out, and that there was a subsequent decline in production during 2017-2018. We estimate that the amount of the CFC-11 bank (the amount of CFC-11 produced, but not yet emitted) in eastern China is up to 112 gigagrams larger in 2019 compared to pre-2013 levels, probably as a result of recent production. Nevertheless, it seems that any substantial delay in ozone-layer recovery has been avoided, perhaps owing to timely reporting 3,4 and subsequent action by industry and government in China 5,6 .

During the summer of 2018, a widespread drought developed over Northern and Central Europe. The increase in temperature and the reduction of soil moisture have influenced carbon dioxide (CO 2 ) exchange between the atmosphere and terrestrial ecosystems in various ways, such as a reduction of photosynthesis, changes in ecosystem respiration, or allowing more frequent fires. In this study, we characterize the resulting perturbation of the atmospheric CO 2 seasonal cycles. 2018 has a good coverage of European regions affected by drought, allowing the investigation of how ecosystem flux anomalies impacted spatial CO 2 gradients between stations. This density of stations is unprecedented compared to previous drought events in 2003 and 2015, particularly thanks to the deployment of the Integrated Carbon Observation System (ICOS) network of atmospheric greenhouse gas monitoring stations in recent years. Seasonal CO 2 cycles from 48 European stations were available for 2017 and 2018. Earlier data were retrieved for comparison from international databases or national networks. Here, we show that the usual summer minimum in CO 2 due to the surface carbon uptake was reduced by 1.4 ppm in 2018 for the 10 stations located in the area most affected by the temperature anomaly, mostly in Northern Europe. Notwithstanding, the CO 2 transition phases before and after July were slower in 2018 compared to 2017, suggesting an extension of the growing season, with either continued CO 2 uptake by photosynthesis and/or a reduction in respiration driven by the depletion of substrate for respiration inherited from the previous months due to the drought. For stations with sufficiently long time series, the CO 2 anomaly observed in 2018 was compared to previous European droughts in 2003 and 2015. Considering the areas most affected by the temperature anomalies, we found a higher CO 2 anomaly in 2003 (+3 ppm averaged over 4 sites), and a smaller anomaly in 2015 (+1 ppm averaged over 11 sites) compared to 2018. This article is part of the theme issue 'Impacts of the 2018 severe drought and heatwave in Europe: from site to continental scale'.

CFCs (chlorofluorocarbons) and other strong ozone-depleting halogenated organic trace gases were used in numerous industrial, household and agriculture applications. First atmospheric measurements of CFCs were performed in the 1970s, well ahead of the detection of the ozone hole in the 1980s. The continuous observation of these ozone-depleting substances (ODSs) is crucial for monitoring their global ban within the Montreal Protocol. In addition, also HFCs (fluorinated hydrocarbons) are measured, which were introduced as substitutes of ODSs and are potent greenhouse gases. Since 2000, Empa continuously measures more than 50 halogenated trace gases at the high-Alpine station of Jungfraujoch (3850 m asl) as part of the global AGAGE network (Advanced Global Atmospheric Gases Experiment). Jungfraujoch is the highest location worldwide where such measurements are performed, and the site where several of these compounds were measured in the atmosphere for the first time. The measurements at Jungfraujoch and at other globally well-positioned sites serve as an early warning system, i. e. before potentially harmful halogenated organic substances can accumulate and detrimentally affect the natural environment.

The recovery of the stratospheric ozone layer relies on the continued decline in the atmospheric concentrations of ozone-depleting gases such as chlorofluorocarbons 1 . The atmospheric concentration of trichlorofluoromethane (CFC-11), the second-most abundant chlorofluorocarbon, has declined substantially since the mid-1990s 2 . A recently reported slowdown in the decline of the atmospheric concentration of CFC-11 after 2012, however, suggests that global emissions have increased 3,4 . A concurrent increase in CFC-11 emissions from eastern Asia contributes to the global emission increase, but the location and magnitude of this regional source are unknown 3 . Here, using high-frequency atmospheric observations from Gosan, South Korea, and Hateruma, Japan, together with global monitoring data and atmospheric chemical transport model simulations, we investigate regional CFC-11 emissions from eastern Asia. We show that emissions from eastern mainland China are 7.0 ± 3.0 (±1 standard deviation) gigagrams per year higher in 2014-2017 than in 2008-2012, and that the increase in emissions arises primarily around the northeastern provinces of Shandong and Hebei. This increase accounts for a substantial fraction (at least 40 to 60 per cent) of the global rise in CFC-11 emissions. We find no evidence for a significant increase in CFC-11 emissions from any other eastern Asian countries or other regions of the world where there are available data for the detection of regional emissions. The attribution of any remaining fraction of the global CFC-11 emission rise to other regions is limited by the sparsity of long-term measurements of sufficient frequency near potentially emissive regions. Several considerations suggest that the increase in CFC-11 emissions from eastern mainland China is likely to be the result of new production and use, which is inconsistent with the Montreal Protocol agreement to phase out global chlorofluorocarbon production by 2010.

Carbon tetrachloride (CCl 4 ) is an ozone-depleting substance, accounting for about 10% of the chlorine in the troposphere. Under the terms of the Montreal Protocol, its production for dispersive uses was banned from 2010. In this work we show that, despite the controls on production being introduced, CCl 4 emissions from the eastern part of China did not decline between 2009 and 2016. This finding is in contrast to a recent bottom-up estimate, which predicted a significant decrease in emissions after the introduction of production controls. We find eastern Asian emissions of CCl 4 to be 16 (9-24) Gg/year on average between 2009 and 2016, with the primary source regions being in eastern China. The spatial distribution of emissions that we derive suggests that the source distribution of CCl 4 in China changed during the 8-year study period, indicating a new source or sources of emissions from China's Shandong province after 2012.

HFO-1234yf (2,3,3,3-tetrafluoropropene) was proposed as an automobile air conditioner (MAC) refrigerant worldwide. However, its atmospheric degradation product is the highly soluble and phytotoxic trifluoroacetic acid (TFA), which persists in aquatic environments. We used a global three-dimensional chemical transport model to assess the potential environmental effects resulting from complete future conversion of the refrigerant in all MAC to HFO-1234yf in China, the United States, and Europe. The annual mean atmospheric concentrations of HFO-1234yf were 2.62, 2.20, and 2.73 pptv, and the mean deposition rates of TFA were 0.96, 0.45, and 0.52 kg km -2 yr -1 , in three regions. The regional TFA deposition sources mainly came from emissions within the same region. The annual TFA deposition in the North Pole region was lower than the global average and mainly originated from European emissions. A potential doubling in the future HFO-1234yf emissions in China mainly affected the local TFA depositions. The TFA concentrations in rainwater were strongly affected by the regional precipitation rates. North Africa and the Middle East, regions with scant rainfall, had extremely high TFA concentrations. The rainwater concentrations of TFA during individual rain events can exceed the level considered to be safe, indicating substantial potential regional risks from future HFO-1234yf use.

The reduction of emissions of mercury is a declared aim of the Minamata Convention, a UN treaty designed to protect human health and the environment from adverse effects of mercury. To assess the effectiveness of the convention in the future, better constraints about the current mercury emissions is a premise. In our study, we applied a top-down approach to quantify mercury emissions on the basis of atmospheric mercury measurements conducted at the remote high altitude monitoring station Jungfraujoch, Switzerland. We established the source-receptor relationships and by the means of atmospheric inversion we were able to quantify spatially resolved European emissions of 89 ± 14 t/a for elemental mercury. Our European emission estimate is 17% higher than the bottom-up emission inventory, which is within stated uncertainties. However, some regions with unexpectedly high emissions were identified. Stationary combustion, in particular in coal-fired power plants, is found to be the main responsible sector for increased emission estimates. Our top-down approach, based on measurements, provides an independent constraint on mercury emissions, helps to improve and refine reported emission inventories, and can serve for continued assessment of future changes in emissions independent from bottom-up inventories.

The Nematomorpha (horsehair worms) and Nematoda (round worms) are sister taxa (together Nematoida) and closely related to Scalidophora (Priapulida, Kinorhyncha, Loricifera). To date, all species were assumed to possess a specific brain type, i.e., the "cycloneuralian" brain that forms a ring-shaped neuropil around the pharynx and is composed of anteriorly and posteriorly located somata. However, descriptions of the nematomorph nervous system are rare and somewhat variable, calling in to question the validity of the cycloneuralian condition. To clarify whether there is a typical cycloneuralian pattern in the nematomorph brain, we investigated the anterior end of Gordius aquaticus with different methods: histology, immunohistochemistry and micro-CT analysis. Three-dimensional reconstructions were made from histological serial sections. The brain is composed of a central neuropil and a ring-shaped structure with associated somata. The unpaired ventral nerve cord emerges from the posteroventral part of the brain. A pharynx/esophagus is absent. In addition to the brain, a peripheral nerve plexus was detected. In summary, we interpret the architecture of the brain as potentially derived from a cycloneuralian structure, but being highly modified. The central position of the neuropil is possibly a consequence of the reduction of the anterior intestinal system as a result of the parasitic lifestyle. The ring-shaped arrangement of the somata may be a remnant of a cycloneuralian arrangement, after the two rings of somata (= cycloneuralian condition) either fused or one ring was reduced to form one massive ring-shaped structure in G. aquaticus. J. Morphol. 278:106-118, 2017. ©© 2016 Wiley Periodicals,Inc., (© 2016 Wiley Periodicals, Inc.)