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Ethane and propane are the most abundant non-methane hydrocarbons in the atmosphere. However, their emissions, atmospheric distribution, and trends in their atmospheric concentrations are insufficiently understood. Atmospheric model simulations using standard community emission inventories do not reproduce available measurements in the Northern Hemisphere. Here, we show that observations of pre-industrial and present-day ethane and propane can be reproduced in simulations with a detailed atmospheric chemistry transport model, provided that natural geologic emissions are taken into account and anthropogenic fossil fuel emissions are assumed to be two to three times higher than is indicated in current inventories. Accounting for these enhanced ethane and propane emissions results in simulated surface ozone concentrations that are 5-13% higher than previously assumed in some polluted regions in Asia. The improved correspondence with observed ethane and propane in model simulations with greater emissions suggests that the level of fossil (geologic + fossil fuel) methane emissions in current inventories may need re-evaluation. © 2018 The Author(s).

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.

The report summaries the activities and results of the greenhouse gas monitoring at the Zeppelin and observatory situated on Svalbard in Arctic Norway during the period 2001-2010 and the greenhouse gas monitoring and aerosol observations from Birkenes for 2010. The monitoring programme is performed by the NILU ¿ Norwegian Institute for Air Research and funded by the Norwegian Pollution Control Authority (SFT) (now Climate and Pollution Agency) and NILU ¿ Norwegian Institute for Air Research.

Volatile organic compounds (VOC) including Benzene-Toluene-Xylene (BTX) related compounds were monitored in ambient air samples during Spring (April-Mai) and Autumn (October) 2010 as a follow-up of an earlier BTX ambient air monitoring program in 2007 (Reimann et al 2007) at the Research park in Longyearbyen (Forskningsparken). In addition, BTX related compounds were measured in 18 ¿headspace¿ samples above collected surface soil along snowmobile tracks in Longyeardalen, Adventdalen, Todalen as well as Sassendalen (Fredheim). In addition, during the 2010 VETAPOS in a parallel surface soil sampling campaign 18 samples were analysed for 15 priority PAH compounds.

The report summaries the activities and results of the greenhouse gas monitoring at the Zeppelin observatory situated on Svalbard in Arctic Norway during the period 2001-2008.The monitoring programme is performed by the Norwegian Institute for Air Research (NILU) and funded by the Norwegian Pollution Control Authority (SFT) (now Climate and Pollution Agency) andNorwegianInstitute for Air Research (NILU).

Norsk institutt for luftforskning (NILU) har utført måleprogram ved Kollsnes prosessanlegg i Øygarden på oppdrag fra Statoil. Dette var et omfattende måleprogram som løp fra desember 2008 - november 2009. To målestasjoner ble benyttet, Blomvåg sør for prosessanlegget og Herdlevær nord for anlegget. Det ble målt meteorologi, NOxog ozon (O3) i luft, støv (PM10, konsentrasjon i luft og nedfall), SO2, tungmetaller (konsentrasjoner i luft og i nedbør), kvikksølv (Hg) i nedbør, hovedkomponenter i nedbør, samt PAH i luft og i nedbør. Luften ved Kollsnes er det man kan kalle ”ren”, dvs. stort sett bakgrunnsluft. Alle gjeldende luftkvalitetskriterier er overholdt, bortsett fra O3. O3 er bestemt av langtransportert forurensning fra kontinentet.

The nitrate radical (NO3) was first measured in the atmosphere in the 1970s and suggestions were made that it could play a major role in oxidising many unsaturated hydrocarbons, such as those emitted from the biosphere. Analysis of the hydrocarbon mix over the North Atlantic Ocean suggested subsequently that the influence of NO3 radical chemistry at night was even more extensive, being on a par with hydroxyl radical chemistry at some times of the year. The paper presents a detailed analysis of an extensive database of many nonmethane hydrocarbons collected at various sites around the North Sea in the mid 1990s during the HANSA project. By comparing the relative rates of oxidation of iso and normal pentane with that of toluene and benzene it clearly shows that the efficiency of NO3 radical chemistry and hydroxyl radical chemistry over northwest Europe are similar in springtime and predicts an average nighttime NO3 concentration of the order of 350 pptv, assuming an annual average OH concentration of 0.6×106 cm-3. This value is very dependant on the average emission ratios of the different hydrocarbons and values between 200 and 600 pptv are possible. It is much larger than direct measurements made in Europe at the surface, but is of the same magnitude as concentrations measured recently from aircraft in the boundary layer over the northeast USA, and previously in vertical profiles by remote sounding over Europe. A simple analytical expression can be derived to calculate the NO3 concentration at night with the only variables being ozone and the loss rate of N2O5, either to the ground or to aerosol surfaces. The concentrations of NO3 calculated in this manner are similar to those derived from the analysis of the HANSA hydrocarbon database for typical conditions expected over Europe, but they are very dependant on the efficiency of the aerosol sink for N2O5. It is shown that NO3 oxidation of many unsaturated hydrocarbons can indeed be more efficient than OH oxidation, especially at times of the year outside the summer season. Direct evidence for hydrocarbon oxidation by NO3 radicals is shown by a series of peroxy radical measurements where the nighttime concentrations can be significantly higher than daytime concentrations in polluted air on occasion. Also the winter/summer (W/S) ratios of many unsaturated hydrocarbons are much lower than those expected from their removal purely by hydroxyl radical chemistry. The consequences of these findings are profound especially as satellite measurements of NO2, a major precursor to NO3, suggest that these high average concentrations of several hundred pptv could be widespread over most of the continents. This needs to be confirmed by direct in-situ measurement of nitrate radicals but it suggests a much larger role for NO3 chemistry in the oxidation capacity of the atmosphere than realised hitherto. © 2006 Elsevier Ltd. All rights reserved.

The report summarises the activities and results of the climate monitoring at the Zeppelin station situated on Svalbard in arctic Norway during year 2001. The measurement programme is performed by the Norwegian Institute for Air Research (NILU) and funded by the Norwegian Pollution Control Authority (SFT).

International audience; abstract simple

This report presents measurements of ozone, non-methane hydrocarbons, sulphate, ammonium, halocarbon and meteorological parameters from Spitsbergen in the Arctic. The focus is the rapid depletion of surface ozone in spring. Trajectories show that the ozone loss is mainly observed when the transport is from W-N. Ozone soundings and surface time series indicate that the loss process is of regional extent. The trace constituents indicate that hydrocarbons are chemically lost, as well as ozone, and that sulphate and ice particles may take part in the reactions.

This report presents regular measurements of nine light non-methane hydrocarbons at South Norway from 1988- 1993. The average seasonal cycle of the concentrations and episodes are shown. Sector analyses based on trajectories are also presented. Calculated trends showed an increase in the acetylene concentration and decreasing alkene concentration.

The Norwegian scientific participation in the Eureka project EUROTRAC 1986-1990 is documented in the report. The main Norwegian activity is centered within TOR (Tropospheric Ozone Research) where measurements are carried. out at Birkenes and Ny-Ålesund on svalbard, and model calculations are done in support of the measurements to interpret atmospheric chemical change both on a European and global scale. There is also Norwegian contributions in Lactoz, Halipp, Glomac and Eumac.

Analysis of spot samples of air taken approx. every second day at a rural site in south Norway for one year showed that alkanes dominated in the samples. Ethane and propane made up about 50% of the total on a C-basis. The sum of C2 - C5 hydrocarbons peaked at 52.6 ppb C in February 1988. The alkanes and acetylene had a distinct late winter peak. while the alkenes had a secondary summer maximum as well. The individual hydrocarbons are quite well correlated with N02 and SO2 but not with O3 or sulphate in air.

Atmospheric measurement techniques 8(7), 2715-2736 (2015). doi:10.5194/amt-8-2715-2015, Published by Copernicus, Katlenburg-Lindau

Μη διαθέσιμη περίληψη Not available summarization Παρουσιάστηκε στο: European Aerosol Conference

Methane stored in seabed reservoirs such as methane hydrates can reach the atmosphere in the form of bubbles or dissolved in water. Hydrates could destabilize with rising temperature further increasing greenhouse gas emissions in a warming climate. To assess the impact of oceanic emissions from the area west of Svalbard, where methane hydrates are abundant, we used measurements collected with a research aircraft (Facility for Airborne Atmospheric Measurements) and a ship (Helmer Hansen) during the Summer 2014 and for Zeppelin Observatory for the full year. We present a model-supported analysis of the atmospheric CH$_{4}$mixing ratios measured by the different platforms. To address uncertainty about where CH$_{4}$ emissions actually occur, we explored three scenarios: areas with known seeps, a hydrate stability model, and an ocean depth criterion. We then used a budget analysis and a Lagrangian particle dispersion model to compare measurements taken upwind and downwind of the potential CH$_{4}$ emission areas. We found small differences between the CH$_{4}$ mixing ratios measured upwind and downwind of the potential emission areas during the campaign. By taking into account measurement and sampling uncertainties and by determining the sensitivity of the measured mixing ratios to potential oceanic emissions, we provide upper limits for the CH$_{4}$ fluxes. The CH$_{4}$ flux during the campaign was small, with an upper limit of 2.5 nmol m$^{-2}$ s$^{-1}$ in the stability model scenario. The Zeppelin Observatory data for 2014 suggest CH$_{4}$ fluxes from the Svalbard continental platform below 0.2 Tg yr$^{-1}$. All estimates are in the lower range of values previously reported., MOCA—Methane Emissions from the Arctic OCean to the Atmosphere: Present and Future Climate Effects is funded by the Research Council of Norway, grant 225814. CAGE—Centre for Arctic Gas Hydrate, Environment and Climate research work was supported by the Research Council of Norway through its Centres of Excellence funding scheme grant 223259. eSTICC—eScience Tools for Investigating Climate Change in northern high latitudes is supported by Nordforsk as Nordic Center of Excellence grant 57001. NERC grants NE/I029293/1 (PI. H. Coe) and NE/I02916/1 (PI J. Pyle) and Methane & Other Greenhouse Gases in the Arctic—Measurements, Process Studies and Modelling (MAMM). The ERC through the ACCI project, project number 267760. The biogenic methane emission data from the LPX-Bern v1.2 model were provided by Renato Spahni. The methane emission data from the GAINS model were provided by IIASA. GFED data are available from http://www.globalfiredata.org/index.html. Airborne data were obtained using the BAe-146-301 Atmospheric Research Aircraft (ARA) flown by Directflight Ltd. and managed by the Facility for Airborne Atmospheric Measurements (FAAM), which is a joint entity of the Natural Environment Research Council (NERC) and the Met Office. Zeppelin and Helmer Hansen atmospheric measurement data are archived in EBAS (http://ebas.nilu.no/) for long-term preservation, access and use. All Zeppelin data for 2014: http://ebas.nilu.no/DataSets.aspx?stations=NO0042G&fromDate=2014-01-01&toDate=2014-12-31. All atmospheric data from RV Helmer Hanssen: http://ebas.nilu.no/DataSets.aspx?stations=NO1000R&fromDate=2014-01-01&toDate=2014-12-31 (password is required until the end of 2017).