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The chemical composition of the upper troposphere/lower stratosphere region (UTLS) is influenced by horizontal transport of air masses, vertical transport within convective systems and warm conveyor belts, rapid turbulent mixing, as well as photochemical production or loss of species. This results in the formation of the extratropical transition layer (ExTL), which is defined by the vertical structure of CO and has been studied until now mostly by means of trace gas correlations. Here, we extend the analysis to include aerosol particles and derive the sulfate–ozone correlation in central Europe from aircraft in situ measurements during the CAFE-EU (Chemistry of the Atmosphere Field Experiment over Europe)/BLUESKY mission. The mission probed the UTLS during the COVID-19 period with significantly reduced anthropogenic emissions. We operated a compact time-of-flight aerosol mass spectrometer (C-ToF-AMS) to measure the chemical composition of non-refractory aerosol particles in the size range from about 40 to 800 nm. In our study, we find a correlation between the sulfate mass concentration and O 3 in the lower stratosphere. The correlation exhibits some variability exceeding the mean sulfate–ozone correlation over the measurement period. Especially during one flight, we observed enhanced mixing ratios of sulfate aerosol in the lowermost stratosphere, where the analysis of trace gases shows tropospheric influence. However, back trajectories indicate that no recent mixing with tropospheric air occurred within the last 10 d. Therefore, we analyzed volcanic eruption databases and satellite SO 2 retrievals from the TROPOspheric Monitoring Instrument (TROPOMI) for possible volcanic plumes and eruptions to explain the high amounts of sulfur compounds in the UTLS. From these analyses and the combination of precursor and particle measurements, we conclude that gas-to-particle conversion of volcanic SO 2 leads to the observed enhanced sulfate aerosol mixing ratios. [ABSTRACT FROM AUTHOR]

Introduction Patients with prurigo nodularis (PN) often report high disease burden with substantial impact on quality of life. Patient Global Impression of Change (PGIC) and Severity (PGIS) are patient self-assessment measures that quantify their experience of disease during treatment. Dupilumab has recently been approved as the first systemic treatment for PN in the US and Europe. Objectives: To evaluate patient-reported global impression of disease severity improvement in dupilumab-treated patients with PN during the LIBERTY-PN PRIME and PRIME 2 trials. Materials & Methods: PRIME and PRIME2 were randomized, double-blind, multicenter, parallel-group, 24-week, phase 3 trials in adults with PN with ≥20 nodules and severe itch, inadequately controlled with topical prescription therapies or for whom these are inadvisable. Patients received 300 mg dupilumab subcutaneously (600 mg loading dose; n = 153) or matched placebo (n = 158) every 2 weeks. In this analysis, data from the two studies were pooled. Patient satisfaction was assessed in the overall placebo group, overall dupilumab-treated group, and those treated with dupilumab who did not achieve the stringent multicomponent endpoint (n = 99) of ≥4-point improvement from baseline in Worst Itch Numerical Rating Scale (WI-NRS, range: 0-10) and an Investigator's Global Assessment PN Stage (IGA PN-S, score range: 0-4) score 0 or 1 (clear or almost clear; ≤5 nodules) at Week (W) 24. Endpoints include proportion of patients achieving: PGIC (range: 0-6) scores of 0 or 1 (very much better or moderately better) at W12, and W24; and PGIS (range: 1-4) score of 1 or 2 (none or mild) at baseline, W12, and W24. Safety was also assessed. Results: Baseline demographic and clinical characteristics were generally similar between groups. In the overall dupilumab and placebo groups, baseline mean (SD) WI-NRS scores were 8.6 (0.9) and 8.4 (1.1), respectively; 32.7% and 34.2% had an IGA PN-S score of 4 (remaining patients had IGA PN-S 3); and mean (SD) PGIS scores were 3.7 (0.5) and 3.7 (0.5) respectively. In dupilumab multicomponent endpoint non-responders, mean (SD) WI-NRS score was 8.6 (0.9). 35.4% and 64.6% had an IGA PN-S score of 4 and 3 respectively; and mean (SD) PGIS score was 3.7 (0.5). At W12, 68.0% vs 38.0% (P < 0.0001 vs placebo) of dupilumab-treated vs placebo-receiving patients achieved PGIC 0 or 1, while 55.6% of dupilumab multicomponent non-responders achieved this endpoint (P = 0.0099 vs placebo). At W24, this increased to 74.5% vs 32.9% (P < 0.0001 vs placebo) of dupilumab-treated vs placebo-receiving patients achieving PGIC 0 or 1, and 61.6% of multicomponent non-achievers (P < 0.0001 vs placebo). At W12, 51.6% vs 22.2% (P < 0.0001 vs placebo) of dupilumab-treated vs placebo-receiving patients achieved PGIS 1 or 2, while 40.4% of multicomponent non-responders achieved the endpoint (P = 0.0027 vs placebo). At W24, 61.4% vs 24.1% (P < 0.0001 vs placebo) of dupilumab-treated vs placebo-receiving patients achieved PGIS 1 or 2, while 44.4% of multicomponent non-responders achieved the endpoint (P = 0.0025 vs placebo). Safety findings were consistent with the known dupilumab safety profile. Conclusions: While not all patients achieved the stringent multicomponent endpoint within the 24-week treatment period during PRIME and PRIME 2 trials, around half of the dupilumab-treated patients still reported significantly more improvement in disease severity and satisfaction with therapy. Overall safety was consistent with the known dupilumab safety profile. [ABSTRACT FROM AUTHOR]

Emissions of land transport and anthropogenic non-traffic emissions (e.g. industry, households and power generation) are significant sources of nitrogen oxides, carbon monoxide, and volatile organic compounds. These emissions are important precursors of tropospheric ozone and affect air quality. The contribution of emission sectors to ozone cannot be mea- sured directly, but calculated with sophisticated models of atmospheric chemistry only. For this study we apply a the MECO(n) model system (MESSy-fied ECHAM and COSMO models nested n times) equipped with a source attribution method to investigate the contribution of anthropogenic (land transport and non-traffic) and biogenic emissions to ozone in Europe. This model system couples a global chemistry-climate mode with a regional chemistry-climate model. Our source attribution (tag- ging) method fully decomposes the budgets of ozone and ozone precursors into contributions from various emission sources and regions. To estimate also the contributions of regional versus long-range transported contributions we distinguish four different source regions: Europe, North America, East Asia and Rest of the World. We performed one simulation covering 2 years with two regional refinements, one covering Europe (50 km resolution), and one covering Central Europe (12 km resolution). The model results are evaluated with data from European air quality stations and in situ data from the flight campaign Effect of Megacities on the Transport and Transformation of Pollutants on the Regional to Global Scales (EMeRGe) Europe in Summer 2017. Two study areas with large anthropogenic emissions, Benelux and Po Valley, are compared in detail. The absolute contributions of European land transport emissions to ground-level ozone for JJA 2017 in the Po Valley are larger than in the Benelux region (7 nmol mol−1 and ≈ 3 nmol mol−1), the same applies for the relative contributions with 12 % in the Po Valley and 7 % in the Benelux regions. Similar results are found for the contribution of European anthropogenic non-traffic emissions. Here, absolute contributions are larger in the Po Valley with 11 nmol mol−1 (19 %) than 5 nmol mol−1 (15 %) in the Benelux regions. The relative contributions to ozone from long-range transported land transport emissions in both regions in the range of 5–6 %, and the relative contributions from long-range transported non-traffic emissions are 9 % in the Po Valley and 13 % in the Benelux region. Contributions to ozone from long-range transported emissions are clearly more homogeneously distributed throughout Europe, whereas the distribution of contributions to ozone from European emissions is notably in-homogeneous. During periods of high ozone, contributions of European land transport and anthropogenic non-traffic emissions increase in particular over the Po Valley and in the Benelux. Especially in the Po Valley the increase is very strong and extreme ozone values could be mitigated in the Po Valley by reducing anthropogenic emissions. [ABSTRACT FROM AUTHOR]

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In this study, airborne measurements of the sum of hydroperoxyl (HO2) and organic peroxy (RO2) radicals that react with nitrogen monoxide (NO) to produce nitrogen dioxide (NO2), coupled with actinometry and other key trace gases measurements, have been used to test the current understanding of the fast photochemistry in the outflow of major population centres. The measurements were made during the airborne campaign of the EMeRGe (Effect of Megacities on the transport and transformation of pollutants on the Regional to Global scales) project in Europe on board the High Altitude and Long Range Research Aircraft (HALO). The measurements of RO 2∗ on HALO were made using the in situ instrument Peroxy Radical Chemical Enhancement and Absorption Spectrometer (PeRCEAS). RO 2∗ is to a good approximation the sum of peroxy radicals reacting with NO to produce NO2. RO 2∗ mixing ratios up to 120 pptv were observed in air masses of different origins and composition under different local actinometric conditions during seven HALO research flights in July 2017 over Europe. Radical production rates were estimated using knowledge of the photolysis frequencies and the RO2∗ precursor concentrations measured on board, as well as the relevant rate coefficients. Generally, high RO2∗ concentrations were measured in air masses with high production rates. In the air masses investigated, RO2∗ is primarily produced by the reaction of O 1 D with water vapour and the photolysis of nitrous acid (HONO) and of the oxygenated volatile organic compounds (OVOCs, e.g. formaldehyde (HCHO) and glyoxal (CHOCHO)). Due to their short lifetime in most environments, the RO 2∗ concentrations are expected to be in a photostationary steady state (PSS), i.e. a balance between production and loss rates is assumed. The RO2∗ production and loss rates and the suitability of PSS assumptions to estimate the RO2∗ mixing ratios and variability during the airborne observations are discussed. The PSS assumption for RO2∗ is considered robust enough to calculate RO2∗ mixing ratios for most conditions encountered in the air masses measured. The similarities and discrepancies between measured and PSS calculated RO2∗ mixing ratios are discussed. The dominant terminating processes for RO2∗ in the pollution plumes measured up to 2000 m are the formation of nitrous acid, nitric acid, and organic nitrates. Above 2000 m, HO2 – HO2 and HO2 – RO2 reactions dominate the RO2∗ removal. RO2∗ calculations by the PSS analytical expression inside the pollution plumes probed often underestimated the measurements. The underestimation is attributed to the limitations of the PSS equation used for the analysis. In particular, this expression does not account for the yields of RO2∗ from the oxidation and photolysis of volatile organic compounds, VOCs, and OVOCs other than those measured during the EMeRGe research flights in Europe. In air masses with NO mixing ratios ≤50 pptv and low VOC/NO ratios, the RO2∗ measured is overestimated by the analytical expression. This may be caused by the formation of H 2 O and O 2 from OH and HO2 , being about 4 times faster than the rate of the OH oxidation reaction of the dominant OVOCs considered. [ABSTRACT FROM AUTHOR]

Sulfur compounds in the upper troposphere and lower stratosphere (UTLS) impact the atmosphere radiation budget, either directly as particles or indirectly as precursor gas for new particle formation. In situ measurements in the UTLS are rare but are important to better understand the impact of the sulfur budget on climate. The BLUESKY mission in May and June 2020 explored an unprecedented situation. (1) The UTLS experienced extraordinary dry conditions in spring 2020 over Europe, in comparison to previous years, and (2) the first lockdown of the COVID-19 pandemic caused major emission reductions from industry, ground, and airborne transportation. With the two research aircraft HALO and Falcon, 20 flights were conducted over central Europe and the North Atlantic to investigate the atmospheric composition with respect to trace gases, aerosol, and clouds. Here, we focus on measurements of sulfur dioxide (SO 2) and particulate sulfate (SO 42-) in the altitude range of 8 to 14.5 km which show unexpectedly enhanced mixing ratios of SO 2 in the upper troposphere and of SO 42- in the lowermost stratosphere. In the UT, we find SO 2 mixing ratios of (0.07±0.01) ppb, caused by the remaining air traffic, and reduced SO 2 sinks due to low OH and low cloud fractions and to a minor extent by uplift from boundary layer sources. Particulate sulfate showed elevated mixing ratios of up to 0.33 ppb in the LS. We suggest that the eruption of the volcano Raikoke in June 2019, which emitted about 1 Tg SO 2 into the stratosphere in northern midlatitudes, caused these enhancements, in addition to Siberian and Canadian wildfires and other minor volcanic eruptions. Our measurements can help to test models and lead to new insights in the distribution of sulfur compounds in the UTLS, their sources, and sinks. Moreover, these results can contribute to improving simulations of the radiation budget in the UTLS with respect to sulfur effects. [ABSTRACT FROM AUTHOR]

Aerosols influence the Earth's energy balance directly by modifying the radiation transfer and indirectly by altering the cloud microphysics. Anthropogenic aerosol emissions dropped considerably when the global COVID-19 pandemic resulted in severe restraints on mobility, production, and public life in spring 2020. We assess the effects of these reduced emissions on direct and indirect aerosol radiative forcing over Europe, excluding contributions from contrails. We simulate the atmospheric composition with the ECHAM5/MESSy Atmospheric Chemistry (EMAC) model in a baseline (business-as-usual) and a reduced emission scenario. The model results are compared to aircraft observations from the BLUESKY aircraft campaign performed in May–June 2020 over Europe. The model agrees well with most of the observations, except for sulfur dioxide, particulate sulfate, and nitrate in the upper troposphere, likely due to a biased representation of stratospheric aerosol chemistry and missing information about volcanic eruptions. The comparison with a baseline scenario shows that the largest relative differences for tracers and aerosols are found in the upper troposphere, around the aircraft cruise altitude, due to the reduced aircraft emissions, while the largest absolute changes are present at the surface. We also find an increase in all-sky shortwave radiation of 0.21 ± 0.05 Wm-2 at the surface in Europe for May 2020, solely attributable to the direct aerosol effect, which is dominated by decreased aerosol scattering of sunlight, followed by reduced aerosol absorption caused by lower concentrations of inorganic and black carbon aerosols in the troposphere. A further increase in shortwave radiation from aerosol indirect effects was found to be much smaller than its variability. Impacts on ice crystal concentrations, cloud droplet number concentrations, and effective crystal radii are found to be negligible. [ABSTRACT FROM AUTHOR]

This paper presents measurements of ozone, water vapour and nitric acid (HNO 3) in the upper troposphere/lower stratosphere (UTLS) over North Atlantic and Europe. The measurements were acquired with the Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) during the Wave Driven Isentropic Exchange (WISE) campaign in October 2017. GLORIA is an airborne limb imager capable of acquiring both 2-D data sets (curtains along the flight path) and, when the carrier aircraft is flying around the observed air mass, spatially highly resolved 3-D tomographic data. Here, we present a case study of a Rossby wave (RW) breaking event observed during two subsequent flights 2 d apart. RW breaking is known to steepen tracer gradients and facilitate stratosphere–troposphere exchange (STE). Our measurements reveal complex spatial structures in stratospheric tracers (ozone and nitric acid) with multiple vertically stacked filaments. Backward-trajectory analysis is used to demonstrate that these features are related to several previous Rossby wave breaking events and that the small-scale structure of the UTLS in the Rossby wave breaking region, which is otherwise very hard to observe, can be understood as stirring and mixing of air masses of tropospheric and stratospheric origin. It is also shown that a strong nitric acid enhancement observed just above the tropopause is likely a result of NO x production by lightning activity. The measurements showed signatures of enhanced mixing between stratospheric and tropospheric air near the polar jet with some transport of water vapour into the stratosphere. Some of the air masses seen in 3-D data were encountered again 2 d later, stretched to very thin filament (horizontal thickness down to 30 km at some altitudes) rich in stratospheric tracers. This repeated measurement allowed us to directly observe and analyse the progress of mixing processes in a thin filament over 2 d. Our results provide direct insight into small-scale dynamics of the UTLS in the Rossby wave breaking region, which is of great importance to understanding STE and poleward transport in the UTLS. [ABSTRACT FROM AUTHOR]

Background: Identifying the optimal treatment in an acute postoperative setting remains a challenge. Multiple analgesic options are available, but comparing outcomes is limited by a lack of head-to-head trials. In addition, decisions based on efficacy only do not take drug safety into account. In such cases, multi-criteria decision analysis (MCDA) can be utilized to quantify and compare the efficacy and safety data of various drugs. Methodology: The efficacy-safety profiles of eight parenteral, postoperative analgesics (acetaminophen, diclofenac, ketorolac, metamizole, morphine, nefopam, parecoxib, tramadol) widely used in Europe were evaluated using an MCDA model that included 17 criteria: three for efficacy and 14 for safety. Each drug was scored on each criterion on a scale from 0 (worst) to 100 (best), according to published data and the judgment of an expert panel. A weighting process was then applied to standardize the impact of each criterion and adjust drugs' preference scores accordingly, normalizing them on the 0– 100 scale. Sensitivity analyses were also performed, including a model in which analgesic profiles were compared when opioid sparing effect was set at a zero value for all drugs. Results: In the primary model, efficacy and safety had relative weightings of 64% and 36%, respectively. Efficacy and safety criteria with the highest values were pain relief (relative weight, 29%) and gastrointestinal effects (12%). Parecoxib received the highest overall score (93), followed by diclofenac (80), and ketorolac (75). Morphine scored the lowest (57), due to the lack of an opioid sparing effect. When opioid sparing was given a zero rating, parecoxib remained the highest scoring analgesic (93), followed by diclofenac (80), metamizole (76), and morphine (76). Parecoxib remained the most preferred analgesic in several other sensitivity analyses. Conclusion: This MCDA-based assessment suggests that parecoxib has the most favorable efficacy-safety profile among the assessed postoperative analgesics. [ABSTRACT FROM AUTHOR]

Poorly controlled pain is a global public health issue. The personal, familial and societal costs are immeasurable. Only a minority of European patients have access to a comprehensive specialist pain clinic. More commonly the responsibility for chronic pain management and initiating opioid therapy rests with the primary care physician and other non-specialist opioid prescribers. There is much confusing and conflicting information available to non-specialist prescribers regarding opioid therapy and a great deal of unjustified fear is generated. Opioid therapy should only be initiated by competent clinicians as part of a multi-faceted treatment programme in circumstances where more simple measures have failed. Throughout, all patients must be kept under close clinical surveillance. As with any other medical therapy, if the treatment fails to yield the desired results and/or the patient is additionally burdened by an unacceptable level of adverse effects, the overall management strategy must be reviewed and revised. No responsible clinician will wish to pursue a failed treatment strategy or persist with an ineffective and burdensome treatment. In a considered attempt to empower and inform non-specialist opioid prescribers, EFIC convened a European group of experts, drawn from a diverse range of basic science and relevant clinical disciplines, to prepare a position paper on appropriate opioid use in chronic pain. The expert panel reviewed the available literature and harnessed the experience of many years of clinical practice to produce these series of recommendations. Its success will be judged on the extent to which it contributes to an improved pain management experience for chronic pain patients across Europe.Significance: This position paper provides expert recommendations for primary care physicians and other non- specialist healthcare professionals in Europe, particularly those who do not have ready access to specialists in pain medicine, on the safe and appropriate use of opioid medications as part of a multi-faceted approach to pain management, in properly selected and supervised patients. [ABSTRACT FROM AUTHOR]

Severe winter storms in combination with precipitation extremes pose a serious threat to Europe. Located at the southeastern exit of the North Atlantic's storm track, European coastlines are directly exposed to impacts by high wind speeds, storm floods and coastal erosion. In this study we analyze potential changes in simulated winter storminess and extreme precipitation, which may occur under 1.5 or 2 °C warming scenarios. Here we focus on a first simulation suite of the atmospheric model CAM5 performed within the HAPPI project and evaluate how changes of the horizontal model resolution impact the results regarding atmospheric pressure, storm tracks, wind speed and precipitation extremes. The comparison of CAM5 simulations with different resolutions indicates that an increased horizontal resolution to 0.25° not only refines regional-scale information but also improves large-scale atmospheric circulation features over the Euro-Atlantic region. The zonal bias in monthly pressure at mean sea level and wind fields, which is typically found in low-resolution models, is considerably reduced. This allows us to analyze potential changes in regional- to local-scale extreme wind speeds and precipitation in a more realistic way. Our analysis of the future response for the 2 °C warming scenario generally confirms previous model simulations suggesting a poleward shift and intensification of the meridional circulation in the Euro-Atlantic region. Additional analysis suggests that this shift occurs mainly after exceeding the 1.5 °C global warming level, when the midlatitude jet stream manifests a strengthening northeastward. At the same time, this northeastern shift of the storm tracks allows an intensification and northeastern expansion of the Azores high, leading to a tendency of less precipitation across the Bay of Biscay and North Sea. Regions impacted by the strengthening of the midlatitude jet, such as the northwestern coasts of the British Isles, Scandinavia and the Norwegian Sea, and over the North Atlantic east of Newfoundland, experience an increase in the mean as well as daily and sub-daily precipitation, wind extremes and storminess, suggesting an important influence of increasing storm activity in these regions in response to global warming. [ABSTRACT FROM AUTHOR]

The article examines the transition of 2014 Hurricane Gonzalo to an extratropical storm in Europe. Topics covered include unusually long track of Gonzalo, interaction of extratropical transition extratropical low pressure systems or upper-level troughs and the findings that despite its strength Gonzalo was within the historical range of transforming storms.

Rationale, aims and objectives Management of post-operative pain is unsatisfactory worldwide. An estimated 240 million patients undergo surgery each year. Forty to 60% of these patients report clinically significant pain. Discrepancy exists between availability of evidence-based medicine ( EBM)-derived knowledge about management of perioperative pain and increased implementation of related practices versus lack of improvement in patient-reported outcomes ( PROs). We aimed to assist health care providers to optimize perioperative pain management by developing and validating a medical registry that measures variability in care, identifies best pain management practices and assists clinicians in decision making. Methods PAIN OUT was established from 2009 to 2012 with funding from the European Commission. It now continues as a self-sustaining, not-for-profit project, targeting health care professionals caring for patients undergoing surgery. Results The growing registry includes data from 40 898 patients, 60 hospitals and 17 countries. Collaborators upload data (demographics, clinical, PROs) from patients undergoing surgery in their hospital/ward into an Internet-based portal. Two modules make use of the data: (1) online, immediate feedback and benchmarking compares PROs across sites while offline analysis permits in-depth analysis; and (2) the case-based clinical decision support system offers practice-based treatment recommendations for individual patients; it is available now as a prototype. The E lectronic K nowledge L ibrary provides succinct summaries on perioperative pain management, supporting knowledge transfer and application of EBM. Conclusion PAIN OUT, a large, growing international registry, allows use of 'real-life' data related to management of perioperative pain. Ultimately, comparative analysis through audit, feedback and benchmarking will improve quality of care. [ABSTRACT FROM AUTHOR]

During the Great Recession mass demonstrations indicated weakened political support in Europe. We show that growing dissatisfaction often reflects poor economic conditions and unemployment is particularly important. Using individual level data for 16 Western European countries for 1976-2010, we find that national economic performance matters even beyond personal economic outcomes. Finally, while the effects of growth and unemployment rates are the same across demographic subsets, the effect of inflation is heterogeneous. Well-educated or working individuals put a relatively higher weight on price stability than the less skilled or not working. Our findings reinforce the political importance of employment and growth policies. [ABSTRACT FROM AUTHOR]

The article focuses on the labour law crisis in Europe regarding distinction between economic and social rights. The European Trade Union Confederation had introduced labour relations with collective action on the free movement rights after denying fundamental rights violation and poor understanding of the industrial relations. It emphasizes the need to incorporate social rights within the employment context to reduce issues that create inequality in protection of domestic and posted workers.

This paper provides an overview of the existing systems of natural hazard insurance in Europe, their structural characteristics and peculiarities. It also 0discusses the difficulties of adaptation of these systems to climate change and the growing number of natural disasters. Using Germany, Austria and Switzerland as examples, the paper demonstrates that based on the status quo, the Swiss monopoly insurance system, which is embedded within a unique direct voting environment, is most able to reduce micro- and macroeconomic disruptions resulting from natural hazards. 'Change in diversity' is seen to offer the best chance to arrive at insurance systems that are prepared for climate change while being adapted to local particularities. Efforts to harmonize national and regional systems as well as top-down EU initiatives are argued to be inadequate. Copyright © 2010 John Wiley & Sons, Ltd and ERP Environment. [ABSTRACT FROM AUTHOR]

Between May 2005 and March 2008 the CARIBIC (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container) observatory was deployed to make atmospheric observations on 42 flights between Frankfurt, Germany and Manila, the Philippines. This nearly 3 year flight series provides information about atmospheric composition in the upper troposphere over Europe and Asia during all seasons and was used to investigate seasonal and regional differences in trace gas distributions and the influence of long range transport and local convection on composition. The flight route was separated into three different regions having characteristic differences in transport and composition; these were Europe and Western Asia (5°E–60°E), Central Asia (60°E–100°E) and Southeast Asia (100°E–125°E). The region over Europe and Western Asia was strongly influenced by air masses from North America, while the region over Southeast Asia was mostly influenced by local emissions, particularly from biomass/biofuel burning as indicated by high levels of acetonitrile and carbon monoxide. Air masses over Central Asia were found to be influenced by both recent convection from the Indian subcontinent and mid-range transport from Europe, Western Asia and the Middle East. Elevated levels of propane and other non-methane hydrocarbons, both with and without concomitant elevations in other trace gases (i.e. carbon monoxide, acetonitrile) was a persistent feature over Central Asia in all seasons except summer, and were particularly prominent in fall. Influences on composition over Central Asia were investigated in detail for a case study from a series of flights in October 2006, where elevated levels of pollutants were found to be the result of convective transport of both biomass/biofuel burning and urban emissions from South Asia and fossil fuel related emissions from Eastern Europe. [ABSTRACT FROM AUTHOR]

The composition of the lower stratosphere is crucial for a quantitative understanding of surface temperatures (e.g. Riese et al., 2012), but subject to large uncertainties due to the variability of and the range of scales of the underlying processes and the spatio temporal variability of the tropopause itself. The seasonal cycle of large scale dynamical processes like diabatic downwelling from the stratosphere or impact from the monsoon systems further affects the structure of the lower stratosphere. We will present a comparison of trace gas measurements of CO, N2O, and ozone from different HALO missions over the Europe and the northern Atlantic (TACTS: September 2012, PGS: December to March 2015/16 and WISE: September to October 2017) to investigate the seasonal cycle the chemical composition and the age structure in the upper troposphere/lower stratosphere (UTLS). To analyse the underlying time scales of transport we will perform comparisons with the chemical Lagrangian model of the stratosphere (ClaMS). For this purpose we will particularly use information from age spectra, which are provided by ClaMS and which are available for each individual data point along the flight track The consistent comparison of simulated chemical tracers with observations in combination with the age spectral information shows a remarkably good agreement of the CO measurements and the ‚young' age fraction (younger than six months). We find a distinct seasonal cycle of tropospheric air in the lowermost stratosphere maximising by the end of summer and a large fraction of aged air by the end of winter as expected. For equivalent latitudes > 50° the fraction of CO-rich young air dominates the extratropical transition layer (ExTL). Its upper boundary corresponds to the location of the tropopause inversion layer (TIL).We extended the campaign based data to the climatological view including the southern hemisphere. The vertical extent of the SH ExTL is less pronounced than in the northern hemisphere particularly during the respective winter. During summer, the northern hemisphere lower stratosphere shows a larger contribution of young air than the southern summer counterpart. [ABSTRACT FROM AUTHOR]