3511. A study of pollutant concentration variability in an urban street under low wind speedsDamien Martin, Catheryn S Price, Iain R. White, Graham Nickless, Adrian Dobre, Dudley E Shallcross, 2008, original scientific article Abstract: The short time‐scale variability in pollutant concentrations in an urban street under very low wind speed conditions and short source–receptor distance has been investigated using the inert tracer sulfur hexafluoride (SF6) as a continuous point‐source (release times ≥ 5 min), and fast detection using separation by gas chromatography coupled with a μ‐electron capture detector (ECD). The results are complex but can be broadly interpreted in terms of horizontal wind speed and direction coherence. Comparisons with a simple dispersion model suggest that observed time‐averaged maximum concentrations approach predicted values, whilst instantaneous maximum concentrations vary greatly and would therefore be difficult to predict.
Keywords: dispersion, tracer, intermittency
Published in RUNG: 17.07.2019; Views: 3129; Downloads: 128
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3512. An estimation of the global emission of methyl bromide from rapeseed (Brassica napus) from 1961 to 20032008, original scientific article Abstract: Gan et al. [Gan, J., Yates, S.R., Ohr, H.D., Sims, J.J., 1998. Production of methyl bromide by terrestrial higher plants. Geophysical Research Letters 25 (19), 3595–3598] have reported that plants of the family Brassicaceae take up bromide from soils and subsequently release methyl bromide (CH3Br) to the atmosphere deriving a significant emission from this source of about 7 Gg(109 g) yr−1. In this study, we determine a yearly global emission rate for CH3Br from one such species, rapeseed, from 1961 to 2003 using data on crop harvest index and growth rate in conjunction with global production data. This study suggests that CH3Br emissions from rapeseed have increased 10-fold from 1961 to 2003 and by a factor of 3–4 since 1980. It also suggests that the geographical distribution of emissions has also changed substantially in the last 40 yr. The annual emission of CH3Br from mustard and cabbage is also estimated; whilst relative levels emitted from these species are less significant, as these crops are continually exploited for new applications CH3Br emissions are set to increase.
Keywords: CH3Br, Rapeseed, Brassica, Ozone, Biosphere
Published in RUNG: 17.07.2019; Views: 2965; Downloads: 0
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3515. Experimental determination of black and brown carbon heating rate from mid-latitudes to the Arctic ocean, and related energy gradientLuca Ferrero, Luca Cataldi, Griša Močnik, Asta Gregorič, Piotr Markuszewski, Przemek Makuch, Paulina Pakszys, Tomek Petelski, E. Bolzacchini, Tymon Zielinski, 2019, published scientific conference contribution abstract Keywords: black carbon, heating rate, Arctic
Published in RUNG: 17.07.2019; Views: 3600; Downloads: 0
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3516. Multi-wavelength aerosol absorption coefficient measurements: instrument inter-comparison and results of source and source-component modellingVera Bernardoni, Luca Ferrero, Francesca Soldan, Sara Valentin, Mario Massabò, Griša Močnik, Asta Gregorič, Marco Cataldi A., Ezio Bolzacchini, Paolo Prati, Gianluigi Valli, Roberta Vecchi, 2019, published scientific conference contribution abstract Keywords: aerosol absorption, method intercomparison
Published in RUNG: 17.07.2019; Views: 3546; Downloads: 0
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3518. Implementation of liquid chromatography coupled to thermal lens spectrometry (HPLC-TLC) in studies of yeats' role in formation of stable pigments in Pinot Noir winesBranka Mozetič Vodopivec, Jelena Topić, Lorena Butinar, Natka Ćurko, Karin Kovačević Ganić, Dorota Korte, Mladen Franko, 2019, published scientific conference contribution abstract Keywords: thermal lens spectrometry, pigments, Pinot Noir wines
Published in RUNG: 16.07.2019; Views: 3598; Downloads: 0
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3520. Determination of bioavailable Fe redox fractions of sediment pore waters by DGT passive sampling and BDS detectionHanna Budasheva, Dorota Korte, Arne Bratkič, Mladen Franko, 2019, published scientific conference contribution abstract Abstract: The bioavailability and toxicity of contaminants in sediments to benthic organisms depend on the speciation of the contaminant [1]. The level of iron supply to sediments creates contrasting chemical pathways, each producing distinctive mineral assemblag- es. Reliable measurement of Fe redox species (Fe2+ and Fe3+) in sediments is essential for studies of pollutants or trace-element cycling. This is, however, a difficult task, because the distribution of chemical species often changes during sampling and storage.
In this work the Diffusive Gradients in Thin-films technique (DGT) is investigated as a passive sampling approach used in combination with photothermal beam deflection spectroscopy (BDS) as a detection method for determination of labile Fe-redox species in sediments and natural waters. DGT offers the advantage of pre-concentration of labile (i.e. bioavailable) Fe species from the total dissolved Fe pool in sediment pore waters [2]. The advantage of using BDS [3-4] is also in avoiding contamination by using additional steps as extraction or pre-concentration. Furthermore, combined DGT-BDS provides 2D information about distribution of Fe2+ and the total Fe content in the resin hydrogels [5].
The goal of this research is to show the repeatability of this technique for determining trace amounts of Fe redox species in environmental samples.
Keywords: beam deflection spectrometry, diffusive gradients in thin-films, iron species
Published in RUNG: 16.07.2019; Views: 3512; Downloads: 0
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