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Hydrofluorocarbons (HFCs) are used in a range of industrial applications and have largely replaced previously used gases (CFCs and HCFCs). HFCs are not ozone-depleting but have large global warming potentials and are, therefore, reported to the United Nations Framework Convention on Climate Change (UNFCCC). Here, we use four independent inverse models to estimate European emissions of the two HFCs contributing the most to global warming (HFC-134a and HFC-125) and of SF6 for the year 2011. Using an ensemble of inverse models offers the possibility to better understand systematic uncertainties in inversions. All systems relied on the same measurement time series from Jungfraujoch (Switzerland), Mace Head (Ireland), and Monte Cimone (Italy) and the same a priori estimates of the emissions, but differed in terms of the Lagrangian transport model (FLEXPART, NAME), inversion method (Bayesian, extended Kalman filter), treatment of baseline mole fractions, spatial gridding, and a priori uncertainties. The model systems were compared with respect to the ability to reproduce the measurement time series, the spatial distribution of the posterior emissions, uncertainty reductions, and total emissions estimated for selected countries. All systems were able to reproduce the measurement time series very well, with prior correlations between 0.5 and 0.9 and posterior correlations being higher by 0.05 to 0.1. For HFC-125, all models estimated higher emissions from Spain + Portugal than reported to UNFCCC (median higher by 390 %) though with a large scatter between individual estimates. Estimates for Germany (+140 %) and Ireland (+850 %) were also considerably higher than UNFCCC, whereas the estimates for France and the UK were consistent with the national reports. In contrast to HFC-125, HFC-134a emissions from Spain + Portugal were broadly consistent with UNFCCC, and emissions from Germany were only 30 % higher. The data suggest that the UK over-reports its HFC-134a emissions to UNFCCC, as the model median emission was significantly lower, by 50 %. An overestimation of both HFC-125 and HFC-134a emissions by about a factor of 2 was also found for a group of eastern European countries (Czech Republic + Poland + Slovakia), though with less confidence since the measurement network has a low sensitivity to these countries. Consistent with UNFCCC, the models identified Germany as the highest national emitter of SF6 in Europe, and the model median emission was only 1 % lower than the UNFCCC numbers. In contrast, the model median emissions were 2–3 times higher than UNFCCC numbers for Italy, France, and Spain + Portugal. The country-aggregated emissions from the different models often did not overlap within the range of the analytical uncertainties formally given by the inversion systems, suggesting that parametric and structural uncertainties are often dominant in the overall a posteriori uncertainty. The current European network of three routine monitoring sites for synthetic greenhouse gases has the potential to identify significant shortcomings in nationally reported emissions, but a denser network would be needed for more reliable monitoring of country-wide emissions of these important greenhouse gases across Europe.

The Paris Agreement requires accurate accounting of greenhouse gases (GHGs) by all countries. Complementary to bottom-up emission inventories, global, regional and national GHG emissions can be estimated using atmospheric measurements and atmospheric models (the "top-down" approach). This report provides an overview of current capabilities, potential, and further perspectives to use the "top-down" approach to evaluate and improve estimates of greenhouse gas emissions in support of the Paris Agreement., JRC.C.5-Air and Climate

Contains fulltext : 169689.pdf (Publisher’s version ) (Open Access) BACKGROUND: Tuberculosis is the world's leading infectious disease killer. We aimed to identify shorter, safer drug regimens for the treatment of tuberculosis. METHODS: We did a randomised controlled, open-label trial with a multi-arm, multi-stage design. The trial was done in seven sites in South Africa and Tanzania, including hospitals, health centres, and clinical trial centres. Patients with newly diagnosed, rifampicin-sensitive, previously untreated pulmonary tuberculosis were randomly assigned in a 1:1:1:1:2 ratio to receive (all orally) either 35 mg/kg rifampicin per day with 15-20 mg/kg ethambutol, 20 mg/kg rifampicin per day with 400 mg moxifloxacin, 20 mg/kg rifampicin per day with 300 mg SQ109, 10 mg/kg rifampicin per day with 300 mg SQ109, or a daily standard control regimen (10 mg/kg rifampicin, 5 mg/kg isoniazid, 25 mg/kg pyrazinamide, and 15-20 mg/kg ethambutol). Experimental treatments were given with oral 5 mg/kg isoniazid and 25 mg/kg pyrazinamide per day for 12 weeks, followed by 14 weeks of 5 mg/kg isoniazid and 10 mg/kg rifampicin per day. Because of the orange discoloration of body fluids with higher doses of rifampicin it was not possible to mask patients and clinicians to treatment allocation. The primary endpoint was time to culture conversion in liquid media within 12 weeks. Patients without evidence of rifampicin resistance on phenotypic test who took at least one dose of study treatment and had one positive culture on liquid or solid media before or within the first 2 weeks of treatment were included in the primary analysis (modified intention to treat). Time-to-event data were analysed using a Cox proportional-hazards regression model and adjusted for minimisation variables. The proportional hazard assumption was tested using Schoelfeld residuals, with threshold p

The effect of intercontinental transport on measurements of nitrogen oxides (NOx) peroxyacetyl nitrate (PAN) and reactive nitrogen species (NOy) at the high altitude site Jungfraujoch (3580 m asl) Switzerland was evaluated using a combination of backward trajectories and chemical filters (NOy to carbon monoxide (CO) ratio). Mixing ratios associated with air masses transported from the planetary boundary layers (PBL) of the three continental source regions Europe North America and Asia and of free tropospheric origin were characterized. The analysis was applied to PAN NOx and NOy measurements of the period 1997 1998 and to a period more than 10 years later covering several months in 2008 and 2009 2010. The results show that the mixing ratios of PAN NOx and NOy are largest in air advected from the European PBL. In contrast to previous studies our results indicate that the springtime maximum in PAN and NOy mixing ratios is largely attributable to air originating from the European PBL whereas air of free tropospheric origin and intercontinental transport contribute less significantly. PAN and NOy mixing ratios in air masses classified as free tropospheric are also highest in spring but substantially lower than those influenced by European PBL air. Air masses last influenced by the North American source region show considerably lower mixing ratios of nitrogen species than European air masses suggesting that a large fraction of NOy is removed during intercontinental transport probably due to washout of soluble species such as HNO3. The seasonal contributions from different source regions to PAN mixing ratios at Jungfraujoch were evaluated. The average European contribution is highest during the warm seasons with 47 57 in 1997 1998 and 61 69 in 2009 2010. The maximum contribution of North American air masses is also observed in the warm season and was about 5 7 in 1997 1998 and 6 10 in 2009 2010. Air from Asian source regions did not make a significant contribution due to the limited number of cases of direct transport from Asia but when they occurred the air masses contained significant pollutant levels. (C) 2012 Elsevier Ltd. All rights reserved.

High frequency, in situ observations from 11 globally distributed sites for the period 1994–2014 and archived air measurements dating from 1978 onward have been used to determine the global growth rate of 1,1-difluoroethane (HFC-152a, CH3CHF2). These observations have been combined with a range of atmospheric transport models to derive global emission estimates in a top-down approach. HFC-152a is a greenhouse gas with a short atmospheric lifetime of about 1.5 years. Since it does not contain chlorine or bromine, HFC-152a makes no direct contribution to the destruction of stratospheric ozone and is therefore used as a substitute for the ozone depleting chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs). The concentration of HFC-152a has grown substantially since the first direct measurements in 1994, reaching a maximum annual global growth rate of 0.84 ± 0.05 ppt yr−1 in 2006, implying a substantial increase in emissions up to 2006. However, since 2007, the annual rate of growth has slowed to 0.38 ± 0.04 ppt yr−1 in 2010 with a further decline to an annual average rate of growth in 2013–2014 of −0.06 ± 0.05 ppt yr−1. The annual average Northern Hemisphere (NH) mole fraction in 1994 was 1.2 ppt rising to an annual average mole fraction of 10.1 ppt in 2014. Average annual mole fractions in the Southern Hemisphere (SH) in 1998 and 2014 were 0.84 and 4.5 ppt, respectively. We estimate global emissions of HFC-152a have risen from 7.3 ± 5.6 Gg yr−1 in 1994 to a maximum of 54.4 ± 17.1 Gg yr−1 in 2011, declining to 52.5 ± 20.1 Gg yr−1 in 2014 or 7.2 ± 2.8 Tg-CO2 eq yr−1. Analysis of mole fraction enhancements above regional background atmospheric levels suggests substantial emissions from North America, Asia, and Europe. Global HFC emissions (so called “bottom up” emissions) reported by the United Nations Framework Convention on Climate Change (UNFCCC) are based on cumulative national emission data reported to the UNFCCC, which in turn are based on national consumption data. There appears to be a significant underestimate ( > 20 Gg) of “bottom-up” reported emissions of HFC-152a, possibly arising from largely underestimated USA emissions and undeclared Asian emissions.

Small number concentrations render it difficult to quantify ice nucleators (IN) in the atmosphere active at warm temperatures. A useful new method for IN measurement based around filter collections is proposed. It makes use of quartz filters used in 24 h PM10 monitoring (720 m(3) air sample). Small subsamples (1.8mm diameter) from the effective filter area and from the clean fringe (blank) are subjected to immersion freezing tests. We applied the method to eight filters from the High Alpine Research Station Jungfraujoch (3580m above sea level) in the Swiss Alps. All filters carried IN active at 7 degrees C and below. Number concentrations of IN active at 8 10 and 12 degrees C were on average 3.3 10.7 and 17.2m( 3) respectively. Several fold larger numbers of IN active at >= 12 degrees C per unit mass of PM10 were found in air masses influenced by Swiss and southern German atmospheric boundary layer air compared to a Saharan dust event. In combination with data on PM10 mass the method may be used to re construct time series of IN number concentrations.

The atmospheric layer closest to the ground is strongly influenced by variable surfacefluxes (emissions, surface deposition) and can therefore be very heterogeneous. Inorder to perform air quality measurements that are representative of a larger domainor a certain degree of pollution, observatories are placed away from population cen-5tres or within areas of specific population density. Sites are often categorised basedon subjective criteria that are not uniformly applied within different administrative do-mains. A novel approach for the assessment of parameters reflecting site represen-tativeness is presented here, taking emissions, deposition and transport towards 34sites covering Western and Central Europe into account. These parameters are di-10rectly inter-comparable among the sites and can be used to select sites that are, onaverage, more or less suitable for data assimilation and comparison with satellite andmodel data. Advection towards these sites was simulated by backward LagrangianParticle Dispersion Modelling (LPDM) to determine the sites’ annual catchment areasfor the year 2005 and advection times of 12, 24 and 48 h. Only variations caused by15emissions and transport during these periods were considered assuming that thesedominate the short-term variability of most but especially short lived trace gases. Theparameters of representativeness derived were compared between sites and a novel,uniform and observation-independent categorisation of the sites based on a clusteringapproach was established. Six groups of European background sites were identified20ranging from very remote coastal to polluted rural sites. These six categories explained50 to 80% of the inter-site variability of median mixing ratios and their standard devia-tion for NO2and O3, while differences between group means of the longer lived tracegas CO were insignificant. The derived annual catchment areas strongly dependedon the applied LPDM and input wind fields, the catchment settings and the year of25analysis. Nevertheless, the parameters of representativeness showed considerablyless variability than the catchment geometry, supporting the robustness of the derivedstation categorisation., Atmospheric Chemistry and Physics, 10 (8), ISSN:1680-7375, ISSN:1680-7367

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 us to capture variations on hourly and diurnal timescales. For CO2 the mean diurnal peak-to-peak amplitude is about 1 μmol mol−1 in spring, autumn and winter and about 2 μmol mol−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., Atmospheric Measurement Techniques, 6 (7), ISSN:1867-1381, ISSN:1867-8548

International audience; Small number concentrations render it difficult to quantify ice nucleators (IN) in the atmosphere active at warm temperatures. A useful new method for IN measurement based around filter collections is proposed. It makes use of quartz filters used in 24 h PM10 monitoring (720 m(3) air sample). Small subsamples (1.8mm diameter) from the effective filter area and from the clean fringe (blank) are subjected to immersion freezing tests. We applied the method to eight filters from the High Alpine Research Station Jungfraujoch (3580m above sea level) in the Swiss Alps. All filters carried IN active at -7 degrees C and below. Number concentrations of IN active at -8, -10, and -12 degrees C were on average 3.3, 10.7, and 17.2m(-3), respectively. Several-fold larger numbers of IN active at >= -12 degrees C per unit mass of PM10 were found in air masses influenced by Swiss and southern German atmospheric boundary layer air, compared to a Saharan dust event. In combination with data on PM10 mass, the method may be used to re-construct time series of IN number concentrations.

Measurements of H2 at the high-altitude site of Jungfraujoch, Switzerland are reported upon for the period of August, 2005–November, 2009. The time series consists of measurements that are primarily representative of free tropospheric background conditions. Highest background H2 mixing ratios were observed in May, while the lowest were observed in November. The mean seasonal H2 peak-to-trough amplitude of 21 parts per billion (ppb, 10-9 dry air mixing ratio) at Jungfraujoch was considerably less than at other stations at similar latitudes and the seasonal minimum in November was comparatively delayed. These differences are primarily attributed to a dampening and delay of the surface soil sink signal during its vertical propagation to the free troposphere. Excess (mixing ratio minus corresponding baseline value) H2 (ΔH2) and excess CO (ΔCO) displayed no significant correlation. This lacking correlation is attributed to H2 removal by soil during transport to Jungfraujoch, thereby significantly altering the ΔH2/ΔCO ratio from traffic combustion sources, which is the largest source of anthropogenic H2 influencing measurements at Jungfraujoch.DOI: 10.1111/j.1600-0889.2010.00509.x

Small number concentrations render it difficult to quantify ice nucleators (IN) in the atmosphere active at warm temperatures. A useful new method for IN measurement based around filter collections is proposed. It makes use of quartz filters used in 24 h PM10 monitoring (720m3 air sample). Small subsamples (1.8mm diameter) from the effective filter area and from the clean fringe (blank) are subjected to immersion freezing tests. We applied the method to eight filters from the High Alpine Research Station Jungfraujoch (3580m above sea level) in the Swiss Alps. All filters carried IN active at −7 °C and below. Number concentrations of IN active at −8, −10, and −12 °C were on average 3.3, 10.7, and 17.2m−3, respectively. Several-fold larger numbers of IN active at −12 °C per unit mass of PM10 were found in air masses influenced by Swiss and southern German atmospheric boundary layer air, compared to a Saharan dust event. In combination with data on PM10 mass, the method may be used to re-construct time series of IN number concentrations.

International audience; In this study we present the seasonal variability of ozone production efficiencies (EN), defined as the net number of ozone molecules produced per molecule of nitrogen oxides (nitrogen oxide (NO) + nitrogen dioxide (NO2)=NOx) oxidized to NOz (total reactive nitrogen (NOy)?NOx) determined from field measurements of a seven-year period (1998?2004) at the Swiss high-alpine research station Jungfraujoch (JFJ), 3580 m a.s.l. This dataset is a unique long-term data series of nitrogen levels in the free troposphere over Central Europe and hence it offers an excellent opportunity to perform such an analysis and provide further evidence to the photochemical origin of the ozone spring maximum at locations of the northern hemisphere distant from nearby pollution sources. Experimentally derived daily EN values have been selected for 571 days out of the 2557 days from 1998 to 2004, from which an average ozone production efficiency of 18.8±1.3 molecules of O3 produced per molecule of NOx oxidized was calculated. This value indicates the great potential and importance of photochemical ozone production in the free troposphere. The monthly means of experimentally derived daily EN values show a seasonal variation with lower values from May to August, which can be probably attributed to more efficient vertical transport of polluted air masses from the atmospheric boundary layer up to JFJ. In agreement, theoretically derived monthly EN values show similar seasonal variation. The ratio NOy/CO, a parameter to assess the aging process that has occurred in an air parcel, was used as a criterion to disaggregate the 571 selected days between undisturbed and disturbed free tropospheric (FT). The monthly means of experimentally derived EN values for the undisturbed FT conditions show a distinct seasonal cycle with higher values in the cold season from November to April. The EN values for undisturbed FT conditions are particularly higher than the respective monthly EN values for disturbed FT conditions from February to October. It should be noted that the monthly EN values of March (EN=35.8) and April (EN=34.9) are among the highest values throughout the year for undisturbed FT conditions at JFJ. These results highlight the key and possibly the dominant role for photochemistry in the observed build-up of tropospheric ozone in the winter-spring transition period.

Net vertical air mass export by thermally driven f\\/lows from the atmospheric boundary layer (ABL) to the free troposphere (FT) above deep Alpine valleys was investigated. The vertical export of pollutants above mountainous terrain is presently poorly represented in global chemistry transport models (GCTMs) and needs to be quantified. Air mass budgets were calculated using aircraft observations obtained in deep Alpine valleys. The results show that on average 3 times the valley air mass is exported vertically per day under fair weather conditions. During daytime the type of valleys investigated in this study can act as an efficient "air pump" that transports pollutants upward. The slope wind system within the valley plays an important role in redistributing pollutants. Nitrogen oxide emissions in mountainous regions are efficiently injected into the FT. This enhances their ozone production efficiency and thus influences tropospheric pollution budgets. Once lifted to the FT above the Alps pollutants are transported horizontally by the synoptic flow and are subject to European pollution export. Forward trajectory studies show that under fair weather conditions two major pathways for air masses above the Alps dominate. Air masses moving north are mixed throughout the whole tropospheric column and further transported eastward towards Asia. Air masses moving south descend within the subtropical high pressure system above the Mediterranean.