Ions species size distribution in particulate matter associated with VOCs and meteorological conditions over an urban region

Airborne particulate matter (PM10, PM2.5, PM1) and volatile organic compounds (benzene, toluene, m,p-xylene, o-xylene) samples were collected during winter and summer seasons of 2005 at two sites, representing an urban and a suburban region of the Greater Athens Area. Urban site traffic emissions were the major contributor to the concentration of PM2.5, PM10, toluene, and xylenes, while benzene and PM1 concentrations were presented in significant spatial variations. K+, Na+, Mg2+, Ca2+, NO3-, Cl- and SO42- ions were analyzed for the chemical characterization of the collected PM samples. The results showed that Na+ cations and SO42- anions were the dominant species, during winter and summer, respectively, in both sites. The analysis of the synoptic scale and mesoscale atmospheric circulation during the experimental periods demonstrated that the meteorological conditions play a key role, not only in the variation but also in the distribution of the ionic concentrations at the three fractions of particulates and the dominant character (alkaline/acidic/neutral) of the particulates at the two sampling sites.     

A GIS-Based Multicriteria Evaluation for Aiding Risk Management <Emphasis Type="Italic">Pinus pinaster</Emphasis> Ait. Forests: A Case Study in Corsican Island,Western Mediterranean Region

Forest management can benefit from decision support tools, including GIS-based multicriteria decision-aiding approach. In the Mediterranean region, Pinus pinaster forests play a very important role in biodiversity conservation and offer many socioeconomic benefits. However, the conservation of this species is affected by the increase in forest fires and the expansion of Matsucoccus feytaudi. This paper proposes a methodology based on commonly available data for assessing the values and risks of P. pinaster forests and to generating maps to aid in decisions pertaining to fire and phytosanitary risk management. The criteria for assessing the values (land cover type, legislative tools for biodiversity conservation, environmental tourist sites and access routes, and timber yield) and the risks (fire and phytosanitation) of P. pinaster forests were obtained directly or by considering specific indicators, and they were subsequently aggregated by means of GIS-based multicriteria analysis. This approach was tested on the island of Corsica (France), and maps to aid in decisions pertaining to fire risk and phytosanitary risk (M. feytaudi) were obtained for P. pinaster forest management. Study results are used by the technical offices of the local administration—Corsican Agricultural and Rural Development Agency (ODARC)—for planning the conservation of P. pinaster forests with regard to fire prevention and safety and phytosanitary risks. The decision maker took part in the evaluation criteria study (weight, normalization, and classification of the values). Most suitable locations are given to target the public intervention. The methodology presented in this paper could be applied to other species and in other Mediterranean regions.     

Competition of Hydrogen and Manganese Ions for Adsorption Sites in Sitka Spruce Litter

The competition of hydrogen and manganese ions for adsorption sites in Sitka spruce litter was investigated in a factorial design, simulated acid rain experiment, which involved leaching of litter with simulated throughfall solutions at three pH levels (5.3, 4.3 and 3.3) and three manganese concentrations (0 to 0.2 mg1^-1). the throughfall solution at the lowest pH was the most efficient in removing exchangeable manganese from litter. the manganese concentration in the leachates was approximately proportional to the hydrogen ion concentration in the simulated throughfall solution. Under field conditions, throughfall manganese concentration also naturally tends to increase as a consequence of enhanced foliar leaching of manganese in response to increasing precipitation acidity. the manganese concentration in the simulated throughfall also affected manganese concentration in the leachates, however, and contributed to a buildup of exchangeable manganese in litter, thus counteracting to some extent possible adverse effects of excess leaching due to increased throughfall acidity.     

PM2.5 and volatile organic compounds (VOCs) in ambient air: a focus on the effect of meteorology

PM(2.5) and VOCs (benzene, toluene, m-p-o-xylenes) concentrations were measured in an urban and a suburban site in Athens, Greece, during the period between April and November 2004. This period, which is considered to be the warmer period in Greece, is characterized by the development of sea-breeze over the Attica Basin. Additionally strong Northern, North-eastern winds called "The Etesians", predominate during the summer months (July-August), acting positively to the dispersion of pollutants. In this campaign, 24 days with sea-breeze development were observed, 15 days with northern winds, 6 days with southern winds while the rest of the days presented no specific wind profile. Maximum concentrations of PM(2.5), VOCs and nitrogen oxides, were detected during the days with sea-breeze, while minimum concentrations during the days with northern winds. Ozone was the only pollutant that appeared to have higher concentrations in the background site and not in the city centre, where benzene presented strong negative correlation with ozone, indicating the photochemical reaction of hydrocarbons that lead to the ozone formation. The BTX ratios were similar for both sites and wind profiles, indicating common sources for those pollutants. T/B ratio ranged in low levels, between 3-5 for site A and 2-5 for site B, suggesting vehicles emissions as the main sources of volatile compounds. Finally, the strong correlations of PM(2.5) and benzene concentrations, between the two sampling sites, indicate that both the city centre and the background site, are affected by the same sources, under common meteorological conditions (sea-breeze, northern winds).     

PM1 and PM2.5 ionic composition and VOCs measurements in two typical apartments in Athens, Greece: investigation of smoking contribution to indoor air concentrations

During the last decades, the air quality of the city of Athens has been quite aggravated. Scientific interest has been focused on health effects caused by both outdoor and indoor air pollution. The purpose of this study was the presentation of results from air quality measurements in two similar typical Athenian apartments in the same suburban area. In addition, smoking contribution is investigated, as it is the main factor which differentiates the two apartments. The results showed that it is the outdoor environment that mainly contributes to the air quality of the non-smokers’ house. In the second apartment, PM_2.5, PM₁, and benzene concentrations were found significantly higher due to smoking activity. In contrast, no clear difference in particulate matter ionic composition between the two areas was observed, although in the smoker’s house, ion concentrations were found elevated. This observation amplifies the assumption that in the smoker’s apartment, significant outdoor sources’ contribution cannot be excluded.     

Recovery of Nd and Dy from rare earth magnetic waste sludge by hydrometallurgical process

This paper describes a hydrometallurgical process for recovering neodymium (Nd) and dysprosium (Dy) from a magnetic waste sludge generated from the Nd–Fe–B(–Dy) manufacturing process. Phase analysis by XRD study revealed Nd(OH)₃ and Fe₂O₃ as main mineral phases, and chemical analysis by ICP showed the contents of 35.1 wt% Nd, 29.5 wt% Fe, 1.1 wt% Dy and 0.5 wt% B. A solution of 1 M HNO₃ + 0.3 M H₂O₂ was used to dissolve up to 98 % Nd and 81 % Dy, while keeping Fe dissolution below 15 % within 10 min. Fe dissolved in solution was completely removed as Fe(OH)₃ at pH 3 followed by precipitation of Nd and Dy with oxalic acid (H₂C₂O₄) and recovered 91.5 % of Nd and 81.8 % of Dy from solution. The precipitate containing Nd and Dy was calcined at 800 °C to obtain Nd₂O₃ as final product with 68 % purity, and final recovery of 69.7 % Nd and 51 % of Dy was reported in this process.