Found 9759 publications. Showing page 321 of 391:
Chemicals of emerging concern (CECs) in coastal waters: Environmental impact & Management strategies
2024
2010
2010
Chemical speciation of fine airborne particles in Abu Dhabi. NILU OR
PM2.5 was sampled at two urban background sites in Abu Dhabi (Khalifa in the city of Abu Dhabi and Bida Zayed) and analysed chemically for further source identification and quantification. Understanding of source contributions to PM2.5 is a prerequisite for the formulation of effective control strategies for PM2.5 emissions.
For both sites, five source factors were identified. Long-range transported aerosol is the largest contributor (~41%) to average PM2.5 mass concentrations at both sites. It gradually forms from SO2, which is possibly emitted into ambient in the Arabian Gulf area, while it is transported to the sites. Mineral dust was found to be the second most important source, contributing ~25% at both sites. It represents an ubiquitous natural contribution of mainly regional origin to particulate matter in Abu Dhabi.
Other source contributions to particle concentrations found at Khalifa identified were: local traffic (15.1%), shipping/industry (10.5%) and sea salt (4.0%). The latter is a natural contribution.
At Bida Zayed, a mixed traffic/industry factor (13.2%) was found, as well as another two factors of natural origin, explaining 11.4% and 8.7%
2013
Chemical speciation of fine airborne particles in Abu Dhabi. NILU OR
Chemical speciation results of PM2.5 filter samples from eight sites in Abu Dhabi are discussed. This is the third interim report, covering a total of 40 filter samples. As one aim of this sampling study was to use the speciation results for health impact studies, samples with high particle loads and high degree of blackness were selected for analysis, and compared to samples with typical particle loads. Particles with diameters less than 2.5 µm were analysed for elements, inorganic ions and carbonaceous fractions.
The most abundant elements were found to be crustal elements, contributing on average 14% to PM2.5 mass. Reconstructing the mass of crustal oxides, approximately 44% of the fine particle mass was estimated to be associated with mineral dust. The concentrations of most heavy metals were below limit values for annual averages at all sites. For nickel, it was found that the Guideline Value may be exceeded at one traffic site.
Inorganic ions (sulphate, nitrate, ammonium, sodium, chloride) explain on average 34% of the PM2.5 mass in Abu Dhabi. Remarkably high sulphate concentrations account for the major part (on average 26%). Particulate sulphate in Abu Dhabi is likely to have both natural (as a result of the local composition of mineral dust) and anthropogenic sources which cannot be separated with the applied analytical methods. An anthropogenic contribution of ~6% comes from the secondary inorganic ions nitrate and ammonium.
Total carbon, which consists of elemental carbon, organic carbon and carbonate carbon contributed on average 14% to PM2.5 mass. About 30% of total carbon was estimated to be carbonate of likely natural origin. Elemental carbon and most organic carbon are expected to be of anthropogenic origin.
PM in Abu Dhabi has a strong signature of natural sources (mineral dust). A detailed apportionment of sources requires further analyses.
2011
This scoping study proposes a methodology to develop indicator(s) on the risk of chemicals on various types of ecosystems, habitats and species. This indicator is designed to answer the very different needs coming from environmental policy and strategies. Its aim is to reflect the consequences of human activities (e.g., farming) on ecosystems taking into account different protection goals that can cover specific or protected habitats (or the relevant communities or species in these habitats) or intensively used areas such as agricultural landscapes, which are very relevant in terms of representativity.
In order to develop such an indicator, the methodological approach retained to calculate maps showing a specific risk, illustrated as different degrees of exceedance of tolerable effect thresholds, is to combine different layers of information on which areas/habitats/ecosystems, contain which species, that are exposed to which amounts of chemicals. Information on the sensitivity of the species towards different toxicological effects, and how sensitive the species are to the applied chemicals, is used as ‘connectors’ between the different layers of spatial information.
The report highlights the data required for the development of such an indicator and their availability through a review of existing databases. A case study illustrates the applicability of the indicator and the need for further development.
ETC/HE
2022
Chemical properties of Arctic aerosol particles collected at the Zeppelin station during the aerosol transition period in May and June of 2004. Report series in aerosol science, No. 92
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