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Kevin C Jones - One of the best experts on this subject based on the ideXlab platform.

  • seasonal variation of Atmospheric organochlorine pesticides and polybrominated diphenyl ethers in parangipettai tamil nadu india implication for Atmospheric Transport
    Science of The Total Environment, 2019
    Co-Authors: Paromita Chakraborty, Gan Zhang, P Sampathkumar, T Balasubramanian, K Kathiresan, Shin Takahashi, Annamalai Subramanian, Shinsuke Tanabe, Kevin C Jones
    Abstract:

    Past studies have reported several persistent organic pollutants (POPs) in different environmental matrices from a tropical coastal site, Parangipettai (PI), located along the bank of the Vellar River in Tamil Nadu, south India. Hence to fill the data gap after the strict ban on several POPs, high volume air sampling was conducted in PI to study the variability of Atmospheric organochlorine pesticides (OCPs) and polybrominated diphenyl ethers (PBDEs) during summer, pre-monsoon and monsoon seasons. Emission source regions were tracked by using five days back trajectory analysis. Range of air concentrations in pg/m3 were: dichlorodiphenyltrichloroethane (DDT), 13 - 1976; hexachlorocyclohexane (HCH), 260-1135, hexachlorocyclobenzene (HCB), 52-135, chlordanes, 36-135 and endosulfans, 66-1013. Six PBDE congeners ranged between 25 and 155 pg/m3 with the highest concentration in summer followed by pre-monsoon and monsoon. Atmospheric DDT and HCH in PI have drastically reduced from the past report thereby showing the strict ban on agricultural use of these compounds. During monsoon, fresh source of o,p'-DDT, trans-chlordane and α-endosulfan was evident. Higher level of endosulphan sulfate in PI seems to be likely affected by the air mass, originating from a neighbouring state Kerela, where endosulfan has been extensively used for cashew plantations. Similarly in summer, the day recorded with the highest level of PBDEs, the sample was concurrently impacted by air parcel comprised of two major clusters, 1 (25%) and 2 (49%) that traversed through the metropolitan cities like Bangalore and Chennai. Dominance of BDE-99 over BDE-47 in PI is in line with the PBDE profile reported from Chennai city during similar time frame. Average concentration of tetra and penta BDE congeners in summer samples were nearly 2-3 folds higher than pre-monsoon or monsoon. Given the fact that strong localised sources for heavier BDE congeners are lacking in PI, regional Atmospheric Transport from the strong emission source regions in Chennai might have impacted PBDE concentration in PI.

  • Atmospheric Transport cycling and dynamics of polychlorinated biphenyls pcbs from source regions to remote oceanic areas occurrence fate and impact of Atmospheric pollutants on environmental and human health
    2013
    Co-Authors: Rosalinda Gioia, Jordi Dachs, Luca Nizzetto, Rainer Lohmann, Kevin C Jones
    Abstract:

    Polychlorinated biphenyls (PCBs) are ubiquitous in the environment. Their persistence coupled with their potential toxicity has prompted international regulations and increased effort to understand their regional and global scale presence, and the processes that influence their fate and Transport. PCBs can travel in the atmosphere away from source regions through long-range Atmospheric Transport and be deposited to water and terrestrial surfaces. This chapter focuses on the Atmospheric concentrations of PCBs and factors controlling their spatial and temporal variability from source regions to oceanic remote areas. Air data show a strong latitudinal trend with the highest PCB concentrations in Europe and the lowest in the Arctic and in the tropical and subtropical southern hemisphere. High PCB levels were observed off the west coast of Africa and Asia, and possible factors controlling these high levels and their implications for the global cycling of PCBs are discussed. Furthermore, air-water interactions are disussed in remote areas of the open ocean. Of particular importance is the evidence for near steady-state air-water equilibrium or net volatilization in the tropical and subtropical regions, while advective inputs still dominate in the Northern hemisphere. Net deposition dominates over volatilization in the Arctic region. This chapter seeks o examine recent findings in the global Transport of PCBs and to identify areas of uncertainty in the understanding of the factors controlling the residence time of PCBs in different areas of the globe.

  • evidence for the grasshopper effect and fractionation during long range Atmospheric Transport of organic contaminants
    Environmental Pollution, 2004
    Co-Authors: Todd Gouin, Donald Mackay, Kevin C Jones, Tom Harner, Sandra N Meijer
    Abstract:

    Although there is indisputable evidence that long-range Atmospheric Transport (LRAT) of organic contaminants occurs on a global scale, uncertainties remain about the detailed mechanism and extent of this phenomenon as well as the physical–chemical properties which facilitate LRAT. In this study, we discuss how mass balance models and monitoring data can contribute to a fuller understanding of the mechanism and extent of LRAT. Specifically we address the issues of “grasshopping” or “hopping” (the extent to which molecules are subject to multiple hops as distinct from a single emission-deposition event) and “global fractionation” (the differing behavior of chemicals as they are Transported). It is shown that simple mass balance models can be used to assist the interpretation of monitoring data while also providing an instrument that can be used to assess the LRAT potential and the extent of hopping that organic substances may experience. The available evidence supports the notion that many persistent organic pollutants experience varying degrees of “hopping” during their environmental journey and as a consequence become fractionated with distance from source.

Andreas Stohl - One of the best experts on this subject based on the ideXlab platform.

  • Atmospheric Transport is a major pathway of microplastics to remote regions
    Nature Communications, 2020
    Co-Authors: Nikolaos Evangeliou, Henrik Grythe, Z Klimont, C Heyes, Sabine Eckhardt, Susana Lopezaparicio, Andreas Stohl
    Abstract:

    In recent years, marine, freshwater and terrestrial pollution with microplastics has been discussed extensively, whereas Atmospheric microplastic Transport has been largely overlooked. Here, we present global simulations of Atmospheric Transport of microplastic particles produced by road traffic (TWPs – tire wear particles and BWPs – brake wear particles), a major source that can be quantified relatively well. We find a high Transport efficiencies of these particles to remote regions. About 34% of the emitted coarse TWPs and 30% of the emitted coarse BWPs (100 kt yr−1 and 40 kt yr−1 respectively) were deposited in the World Ocean. These amounts are of similar magnitude as the total estimated direct and riverine Transport of TWPs and fibres to the ocean (64 kt yr−1). We suggest that the Arctic may be a particularly sensitive receptor region, where the light-absorbing properties of TWPs and BWPs may also cause accelerated warming and melting of the cryosphere. Plastic pollution is a critical concern across diverse ecosystems, yet most research has focused on terrestrial and aquatic Transport, neglecting other mechanisms. Here the authors show that Atmospheric Transport is a major pathway for road plastic pollution over remote regions.

  • long term trends of black carbon and sulphate aerosol in the arctic changes in Atmospheric Transport and source region emissions
    Atmospheric Chemistry and Physics, 2010
    Co-Authors: D Hirdman, Sabine Eckhardt, John F Burkhart, Harald Sodemann, Anne Jefferson, Patricia K Quinn, Sandeep Sharma, Johan Strom, Andreas Stohl
    Abstract:

    Abstract. As a part of the IPY project POLARCAT (Polar Study using Aircraft, Remote Sensing, Surface Measurements and Models, of Climate, Chemistry, Aerosols and Transport) and building on previous work (Hirdman et al., 2010), this paper studies the long-term trends of both Atmospheric Transport as well as equivalent black carbon (EBC) and sulphate for the three Arctic stations Alert, Barrow and Zeppelin. We find a general downward trend in the measured EBC concentrations at all three stations, with a decrease of −2.1±0.4 ng m−3 yr−1 (for the years 1989–2008) and −1.4±0.8 ng m−3 yr−1 (2002–2009) at Alert and Zeppelin respectively. The decrease at Barrow is, however, not statistically significant. The measured sulphate concentrations show a decreasing trend at Alert and Zeppelin of −15±3 ng m−3 yr−1 (1985–2006) and −1.3±1.2 ng m−3 yr−1 (1990–2008) respectively, while there is no trend detectable at Barrow. To reveal the contribution of different source regions on these trends, we used a cluster analysis of the output of the Lagrangian particle dispersion model FLEXPART run backward in time from the measurement stations. We have investigated to what extent variations in the Atmospheric circulation, expressed as variations in the frequencies of the Transport from four source regions with different emission rates, can explain the long-term trends in EBC and sulphate measured at these stations. We find that the long-term trend in the Atmospheric circulation can only explain a minor fraction of the overall downward trend seen in the measurements of EBC (0.3–7.2%) and sulphate (0.3–5.3%) at the Arctic stations. The changes in emissions are dominant in explaining the trends. We find that the highest EBC and sulphate concentrations are associated with Transport from Northern Eurasia and decreasing emissions in this region drive the downward trends. Northern Eurasia (cluster: NE, WNE and ENE) is the dominant emission source at all Arctic stations for both EBC and sulphate during most seasons. In wintertime, there are indications that the EBC emissions from the eastern parts of Northern Eurasia (ENE cluster) have increased over the last decade.

  • characteristics of Atmospheric Transport into the arctic troposphere
    Journal of Geophysical Research, 2006
    Co-Authors: Andreas Stohl
    Abstract:

    [1] The Lagrangian particle dispersion model FLEXPART was used to construct a global data set of 1.4 million continuous trajectories. At the model start, particles were distributed homogeneously in the atmosphere and were then Transported for 5.5 years using both resolved winds from European Centre for Medium-Range Weather Forecasts analyses and parameterized turbulent and convective Transport. On the basis of this data set, a climatology of Transport in and to the Arctic was developed. It was found that the time air resides continuously north of 70°N, called its Arctic age, is highest near the surface in the North American sector of the Arctic. North of 80°N and near the surface, the mean Arctic age of air is about 1 week in winter and 2 weeks in summer. It decreases rapidly with altitude to about 3 days in the upper troposphere. In the most isolated regions of the Arctic, air is exposed to continuous darkness for, on average, 10–14 days in December. Transport from the stratosphere to the lower troposphere is much slower in the Arctic than in the middle latitudes. In the central Arctic, for instance, the probability that air near the surface was Transported from the stratosphere within 10 days is only about 1% in winter and 0.3% in summer. Air pollution can be Transported into the Arctic along three different pathways: low-level Transport followed by ascent in the Arctic, low-level Transport alone, and uplift outside the Arctic, followed by descent in the Arctic. Only this last pathway is frequent for pollution originating from North America and Asia, whereas European pollution can follow all three pathways in winter, and pathways one and three in summer. Sensitivities of Arctic air masses to emissions of air pollutants, based on Transport alone, were calculated for times of up to 30 days before the air masses reached the Arctic. They were highest over Siberia and Europe in winter and over the oceans in summer. Using an inventory for anthropogenic black carbon (BC) emissions, it was found that near the surface and for Transport timescales of 5 and 10 days, BC source contributions from south Asia are only 1.6% and 10%, respectively, of the corresponding European values, despite much higher emissions in south Asia. Using an inventory for BC emissions from forest fires, BC source contributions to the Arctic, particularly from fires in Siberia, were larger than anthropogenic BC source contributions in summer in years of average burning.

  • technical note the lagrangian particle dispersion model flexpart version 6 2
    Atmospheric Chemistry and Physics, 2005
    Co-Authors: Andreas Stohl, C Forster, A Frank, Petra Seibert, Gerhard Wotawa
    Abstract:

    Abstract. The Lagrangian particle dispersion model FLEXPART was originally (about 8 years ago) designed for calculating the long-range and mesoscale dispersion of air pollutants from point sources, such as after an accident in a nuclear power plant. In the meantime FLEXPART has evolved into a comprehensive tool for Atmospheric Transport modeling and analysis. Its application fields were extended from air pollution studies to other topics where Atmospheric Transport plays a role (e.g., exchange between the stratosphere and troposphere, or the global water cycle). It has evolved into a true community model that is now being used by at least 25 groups from 14 different countries and is seeing both operational and research applications. A user manual has been kept actual over the years and was distributed over an internet page along with the model's source code. In this note we provide a citeable technical description of FLEXPART's latest version (6.2).

Paul W Eslinger - One of the best experts on this subject based on the ideXlab platform.

  • international challenge to model the long range Transport of radioxenon released from medical isotope production to six comprehensive nuclear test ban treaty monitoring stations
    Journal of Environmental Radioactivity, 2018
    Co-Authors: Christian Maurer, Paul W Eslinger, Petra Seibert, Jonathan Bare, Jolanta Kusmierczykmichulec, Alice M Crawford, Anne Philipp, Ole Ross, S Generoso, Pascal Achim
    Abstract:

    Abstract After performing a first multi-model exercise in 2015 a comprehensive and technically more demanding Atmospheric Transport modelling challenge was organized in 2016. Release data were provided by the Australian Nuclear Science and Technology Organization radiopharmaceutical facility in Sydney (Australia) for a one month period. Measured samples for the same time frame were gathered from six International Monitoring System stations in the Southern Hemisphere with distances to the source ranging between 680 (Melbourne) and about 17,000 km (Tristan da Cunha). Participants were prompted to work with unit emissions in pre-defined emission intervals (daily, half-daily, 3-hourly and hourly emission segment lengths) and in order to perform a blind test actual emission values were not provided to them. Despite the quite different settings of the two Atmospheric Transport modelling challenges there is common evidence that for long-range Atmospheric Transport using temporally highly resolved emissions and highly space-resolved meteorological input fields has no significant advantage compared to using lower resolved ones. As well an uncertainty of up to 20% in the daily stack emission data turns out to be acceptable for the purpose of a study like this. Model performance at individual stations is quite diverse depending largely on successfully capturing boundary layer processes. No single model-meteorology combination performs best for all stations. Moreover, the stations statistics do not depend on the distance between the source and the individual stations. Finally, it became more evident how future exercises need to be designed. Set-up parameters like the meteorological driver or the output grid resolution should be pre-scribed in order to enhance diversity as well as comparability among model runs.

  • estimates of radioxenon released from southern hemisphere medical isotope production facilities using measured air concentrations and Atmospheric Transport modeling
    Journal of Environmental Radioactivity, 2014
    Co-Authors: Paul W Eslinger, H S Miley, Judah I Friese, Justin D Lowrey, Justin I Mcintyre, Brian T Schrom
    Abstract:

    Abstract The International Monitoring System (IMS) of the Comprehensive-Nuclear-Test-Ban-Treaty monitors the atmosphere for radioactive xenon leaking from underground nuclear explosions. Emissions from medical isotope production represent a challenging background signal when determining whether measured radioxenon in the atmosphere is associated with a nuclear explosion prohibited by the treaty. The Australian Nuclear Science and Technology Organisation (ANSTO) operates a reactor and medical isotope production facility in Lucas Heights, Australia. This study uses two years of release data from the ANSTO medical isotope production facility and 133 Xe data from three IMS sampling locations to estimate the annual releases of 133 Xe from medical isotope production facilities in Argentina, South Africa, and Indonesia. Atmospheric dilution factors derived from a global Atmospheric Transport model were used in an optimization scheme to estimate annual release values by facility. The annual releases of about 6.8 × 10 14  Bq from the ANSTO medical isotope production facility are in good agreement with the sampled concentrations at these three IMS sampling locations. Annual release estimates for the facility in South Africa vary from 2.2 × 10 16 to 2.4 × 10 16  Bq, estimates for the facility in Indonesia vary from 9.2 × 10 13 to 3.7 × 10 14  Bq and estimates for the facility in Argentina range from 4.5 × 10 12 to 9.5 × 10 12  Bq.

  • source term estimation of radioxenon released from the fukushima dai ichi nuclear reactors using measured air concentrations and Atmospheric Transport modeling
    Journal of Environmental Radioactivity, 2014
    Co-Authors: Paul W Eslinger, Steven R Biegalski, Ted W Bowyer, M W Cooper, Derek A Haas, James C Hayes, Ian Hoffman, Ed Korpach, Jing Yi, H S Miley
    Abstract:

    Abstract Systems designed to monitor airborne radionuclides released from underground nuclear explosions detected radioactive fallout across the northern hemisphere resulting from the Fukushima Dai-ichi Nuclear Power Plant accident in March 2011. Sampling data from multiple International Modeling System locations are combined with Atmospheric Transport modeling to estimate the magnitude and time sequence of releases of 133Xe. Modeled dilution factors at five different detection locations were combined with 57 Atmospheric concentration measurements of 133Xe taken from March 18 to March 23 to estimate the source term. This analysis suggests that 92% of the 1.24 × 1019 Bq of 133Xe present in the three operating reactors at the time of the earthquake was released to the atmosphere over a 3 d period. An uncertainty analysis bounds the release estimates to 54–129% of available 133Xe inventory.

F Ruggieri - One of the best experts on this subject based on the ideXlab platform.

Gerhard Wotawa - One of the best experts on this subject based on the ideXlab platform.

  • estimation of the time dependent radioactive source term from the fukushima nuclear power plant accident using Atmospheric Transport modelling
    Journal of Environmental Radioactivity, 2012
    Co-Authors: Michael Schoppner, Wolfango Plastino, P P Povinec, Gerhard Wotawa, F Bella, A Budano, Mario De Vincenzi, F Ruggieri
    Abstract:

    Abstract Caesium-137 and Iodine-131 radionuclides released after the Fukushima Dai-ichi nuclear power plant accident in March 2011 were detected at monitoring stations throughout the world. Using the CTBT radionuclide data and the assumption that the Fukushima accident was the only source of these radionuclides, it was possible to estimate their time-dependent source-term fourteen days following the accident by using Atmospheric Transport modelling. A reasonable agreement was obtained between the modelling results and the estimated radionuclide release rates from the Fukushima accident.

  • technical note the lagrangian particle dispersion model flexpart version 6 2
    Atmospheric Chemistry and Physics, 2005
    Co-Authors: Andreas Stohl, C Forster, A Frank, Petra Seibert, Gerhard Wotawa
    Abstract:

    Abstract. The Lagrangian particle dispersion model FLEXPART was originally (about 8 years ago) designed for calculating the long-range and mesoscale dispersion of air pollutants from point sources, such as after an accident in a nuclear power plant. In the meantime FLEXPART has evolved into a comprehensive tool for Atmospheric Transport modeling and analysis. Its application fields were extended from air pollution studies to other topics where Atmospheric Transport plays a role (e.g., exchange between the stratosphere and troposphere, or the global water cycle). It has evolved into a true community model that is now being used by at least 25 groups from 14 different countries and is seeing both operational and research applications. A user manual has been kept actual over the years and was distributed over an internet page along with the model's source code. In this note we provide a citeable technical description of FLEXPART's latest version (6.2).

  • Atmospheric Transport modelling in support of ctbt verification overview and basic concepts
    Atmospheric Environment, 2003
    Co-Authors: Gerhard Wotawa, Larserik De Geer, Philippe Denier, Martin Kalinowski, H Toivonen, Real Damours, Franco Desiato, Jeanpierre Issartel
    Abstract:

    Abstract Under the provisions of the Comprehensive Nuclear-Test-Ban Treaty (CTBT), a global monitoring system comprising different verification technologies is currently being set up. The network will include 80 radionuclide (RN) stations distributed all over the globe that measure treaty-relevant radioactive species. While the seismic subsystem cannot distinguish between chemical and nuclear explosions, RN monitoring would provide the “smoking gun” of a possible treaty violation. Atmospheric Transport modelling (ATM) will be an integral part of CTBT verification, since it provides a geo-temporal location capability for the RN technology. In this paper, the basic concept for the future ATM software system to be installed at the International Data Centre is laid out. The system is based on the operational computation of multi-dimensional source–receptor sensitivity fields for all RN samples by means of adjoint tracer Transport modelling. While the source–receptor matrix methodology has already been applied in the past, the system that we suggest will be unique and unprecedented, since it is global, real-time and aims at uncovering source scenarios that are compatible with measurements. Furthermore, it has to deal with source dilution ratios that are by orders of magnitude larger than in typical Transport model applications. This new verification software will need continuous scientific attention, and may well provide a prototype system for future applications in areas of environmental monitoring, emergency response and verification of other international agreements and treaties.