Precipitation scavenging of particle-bound contaminants – A case study of PCDD/Fs

Precipitation scavenging of particles is a major mechanism for atmospheric deposition of organic contaminants, but there have been few field studies. We studied precipitation scavenging of PCDD/Fs with the aim of deepening understanding of environmental variables influencing this process. Bulk deposition of PCDD/Fs and their concentrations in ambient air measured at a background site in Sweden were used to calculate precipitation scavenging ratios. Contrary to expectations, increasing scavenging ratios with decreasing degree of chlorination of the PCDD/F congeners were observed when the particle-associated PCDD/F concentrations in air were used for the calculation. This was attributed to differences in temperature and thereby in the gas – particle partitioning of the PCDD/Fs between ground level and clouds where much of the particle scavenging occurs. When the particle-associated PCDD/F concentrations were recalculated for a 10–20 °C lower temperature, the scavenging ratios of the different PCDD/F congeners were similar. Hence differences between ground level and in-cloud temperature should be considered when calculating scavenging ratios from field observations and when modeling this process. The scavenging ratios averaged ～200 000, with lower values when the particle-associated PCDD/F concentration in air was lower. The soot concentration in air was a good predictor of bulk deposition of PCDD/Fs.     

TiO2 nanoparticles – Relationship between dispersion preparation method and ecotoxicity in the algal growth test

Abstract Purpose Little is known about the ecotoxicity of nanomaterials and there are no specific guidelines for sample preparation and testing. We set out to establish whether the method used to prepare TiO₂ dispersions had a significant impact on aquatic ecotoxicity. We also followed the formation of agglomerates during the incubation period.     

Bench-scale gasification of cedar wood – Part II: Effect of Operational conditions on contaminant release

Here, we present the evolution profile of tar in the product gas during cedar biomass gasification. We also discuss the evolution of other contaminants (H₂S, COS, NH₃, HCN, and HCl). The cedar wood was gasified under various operating conditions in a bench-scale externally heated updraft gasifier; this was followed by thermal reforming.Tar levels in the product gas were significantly affected by the operating conditions used. At a gasification temperature of 923 K, there was no clear relation between the evolution of phenolic tar in the product gas as a function of residence time. The evolution of PAH tar at a low gasification temperature was lower than the evolution of phenolic tar. With increasing temperature, the proportion of PAH tar content became significant. At a gasification temperature of 1223 K, increasing the residence time reduced the content of PAH tar owing to a catalytic effect associated with ash generation at high temperatures. Increasing the steam-to-carbon (S/C) ratio under thermal conditions had a slight effect on PAH conversion. However, increasing the equivalence ratio (ER) effectively reduced the tar levels.The conversion of fuel-sulfur and fuel-nitrogen to volatile-sulfur and volatile-nitrogen, respectively, increased with increasing S/C ratio and ER. The evolutions of COS and HCN gases were much smaller than the evolution of H₂S and NH₃. The evolution of HCl in the product gas decreased slightly with increasing ER. Increasing the S/C ratio decreased the HCl levels in the product gas. The effect of temperature on contaminant levels could not be fully understood due to limited availability of experimental data at various temperatures. We also compare our findings with data in the literature.     

Electron paramagnetic resonance (EPR) investigations of lichens – 1: effects of air pollution

Electron paramagnetic resonance (EPR) investigations were carried out on more than 800 samples of lichens from Lower Silesia, southwest Poland. A statistically confirmed correlation between annual average concentration of sulphur dioxide in the atmosphere and concentration of semiquinone radicals in Hypogymnia physodes thalli was found. Similar results were obtained for Umbilicaria species from the Karkonosze Mountains. Distribution of semiquinone radicals in lichen thalli was also investigated. The action of nitrogen dioxide on Umbilicaria species resulted in the synthesis of iminoxy radicals in the thalli. The intensification of the semiquinone free radical production in lichen thalli from atmospherically polluted environments and the degradation of lichen acids to β-diketone compounds would appear to be parallel processes. The properties of the iminoxyls derived from β-diketones in the lichen matrix (anisotropic spectra at room temperature) and in organic solutions after extraction procedure were also examined by EPR.     

Bench-scale gasification of cedar wood – Part I: Effect of operational conditions on product gas characteristics

The present study was conducted within the framework of R&D activities on the development of gasification and reforming technologies for energy and chemical recovery from biomass resources. Gasification of the Japanese cedar wood has been investigated under various operating conditions in a bench-scale externally heated updraft gasifier; this was followed by thermal reforming. Parametric tests by varying the residence times, gasification temperatures, equivalence ratios (ERs) and steam-to-carbon (S/C) ratios were performed to determine their effects on the product gas characteristics. Thermodynamic equilibrium calculations were preformed to predict the equilibrium gas composition and compared with the experimental value.We found that the product gas characteristics in terms of the H₂/CO ratio, CO₂/CO ratio, and CH₄ and lighter hydrocarbons concentrations are significantly affected by the operating conditions used. Increasing the residence time decreased the CO₂/CO ratio; however, a nominal effect was noticed on H₂ concentration as a function of the residence time. At sufficient residence time, increasing the temperature led to higher H₂ yields, CO efficiency and higher heating value (HHV) of the product gas. The presence of steam during gasification effectively enhanced the proportion of H₂ in the product gas. However, higher S/C ratio reduced the HHV of the product gas. Increasing the ER from 0 to 0.3 increased the H₂ yields and CO efficiency and decreased the HHV of the product gas.The evolution of CH₄ and lighter hydrocarbons at low gasification temperatures was relatively higher than that at high temperature gasification. The evolution of CH₄ and lighter hydrocarbons at high gasification temperatures hardly varied over the investigated operating conditions.     

Bioclimate and city planning – open space planning

The planning and using of open spaces in urban areas very much depend on the shading of the surrounding building structures. This article presents a method for the investigation of the sunlight and the bioclimatic conditions in dependence on the surrounding buildings. It is illustrated for typical courtyards in Berlin, Germany, as one type of open spaces. The programme HelioDat determines the shading of any spot of an open space. It gives the possible duration of direct sunlight for the selected spot for each day of the year. The sunlight conditions in the courtyards differ from one another a lot in dependence on their size the tallness of the surrounding buildings. The calculation of the PMV on the basis of the results of the programme HelioDat determine the bioclimatic situation in the discussed courtyards. Although the results of HelioDat are only one input among the weather conditions and the personal characteristics of the test-person, the bioclimatic conditions correlate very much with the sunlight conditions. In a projected building structure, the sunlight conditions vary a lot between the present situation and the two architectural alternatives. Since the bioclimatic situation is correlated to the sunlight conditions, this example demonstrates the importance for the investigation of the sunlight conditions and the bioclimate already during the planning process of buildings.     

Lidar-assisted measurement of PM10 emissions from agricultural tilling in California's San Joaquin Valley – Part I: lidar

Vertical profiling with point samplers is an accepted method for quantifying the fluxes of PM₁₀ from non-point fugitive dust sources, but is limited by uncertainty in estimates of the actual height of the dust plume, especially for plumes that exceed the highest sampling height. Agricultural land preparation operations in the San Joaquin Valley were monitored using upwind–downwind vertical PM₁₀ profiles and data collected during the first successful experiment to include light detection and ranging (lidar), in 1998, were analyzed to provide modeling criteria for the 1996 and 1997 data. A series of six comprehensive PM₁₀ tests with concurrent lidar data was examined to: (a) develop a framework for analyzing upwind–downwind point PM₁₀ concentration profiles of land preparation operations (disking, listing, root cutting, and ripping) and (b) identify conditions under which the field sampling strategies affect the reproducibility of PM₁₀ concentration measurements. Lidar data were used to verify that the plume heights and shapes extrapolated from the point sampler vertical profiles adequately described the plumes. The shortcomings of the vertical profiling technique and lidar methods are discussed in the light of developing efficient robust methods for accurate PM₁₀ emissions quantification from complex non-point sources.     

Amino acids in dew – origin and seasonal variation

At two sites in the Armenhof district, 10 km east of Fulda, Germany, dew samples were collected from June 1996 to June 1997 and investigated for free and protein-bound amino acids. On account of the high pollen content, at the beginning of June 1996 and in May 1997 total amino acid concentrations were 53–390 μmol l⁻¹, in one sample 922 μmol l⁻¹. At other times the concentration in dew was 8–164 μmol l⁻¹. On 4 and 5 June 1996 the diluted free amino acid fraction (DFAA) of the total hydrolysed amino acids (THAA) at both sites amounted to 35–44% and was predominantly arginine, proline and glutamine/glutamate. Likewise on 11 March 1997 the fraction of DFAA was found to be 39.5% with extremely high arginine and proline fractions. At other times the DFAA-fraction was in the range 14–26%. From July 1996 to June 1997 the amino acid concentrations in the vapours rising from a meadow were also measured and it ranged from 8 to 51 μmol l⁻¹. From July to October 1996 the amino acid composition in the hydrolysates of dew samples and meadow vapours collected overnight were almost identical. The DFAA fraction in the condensation water collected overnight from the meadow varied from 18 to 40%. From 4 to 6 June 1996, on 11 and 13 March 1997 and in the period 16–20 May 1997, the amino acid distribution in dew showed much variation. The percentage fraction of arginine and proline in the hydrolysate increased greatly, whereas that of glycine and serine decreased. The large increase in proline and arginine in hydrolysate is attributable solely to the large amounts of free arginine and proline. This effect occurred in both 1996 and 1997 over several days at both sites at any one time and therefore appears confirmed.     

Atmospheric composition change – global and regional air quality

Air quality transcends all scales with in the atmosphere from the local to the global with handovers and feedbacks at each scale interaction. Air quality has manifold effects on health, ecosystems, heritage and climate. In this review the state of scientific understanding in relation to global and regional air quality is outlined. The review discusses air quality, in terms of emissions, processing and transport of trace gases and aerosols. New insights into the characterization of both natural and anthropogenic emissions are reviewed looking at both natural (e.g. dust and lightning) as well as plant emissions. Trends in anthropogenic emissions both by region and globally are discussed as well as biomass burning emissions. In terms of chemical processing the major air quality elements of ozone, non-methane hydrocarbons, nitrogen oxides and aerosols are covered. A number of topics are presented as a way of integrating the process view into the atmospheric context; these include the atmospheric oxidation efficiency, halogen and HO_x chemistry, nighttime chemistry, tropical chemistry, heat waves, megacities, biomass burning and the regional hot spot of the Mediterranean. New findings with respect to the transport of pollutants across the scales are discussed, in particular the move to quantify the impact of long-range transport on regional air quality. Gaps and research questions that remain intractable are identified. The review concludes with a focus of research and policy questions for the coming decade. In particular, the policy challenges for concerted air quality and climate change policy (co-benefit) are discussed.     

Aromatic hydrocarbons in the atmospheric environment – Part II: univariate and multivariate analysis and case studies of indoor concentrations

The concentrations of the aromatic hydrocarbons benzene, toluene, ethylbenzene and the isomeric xylenes (BTEX) have been determined in the indoor air of 115 private non-smoker homes (∼380 individual rooms) situated in areas with an extreme traffic situation, i.e. in city streets (street canyons) with high traffic density and in rural areas with hardly any traffic at all. The influence of the traffic on the indoor concentration was apparent in the high traffic area. In order to identify other factors influencing the BTEX concentrations, the data and additional questionnaires were analyzed by univariate and multivariate analysis. The analysis was supplemented by some case studies. It is shown that meteorology (the seasons), the type of room (e.g. living room versus bedroom), the ventilation and, in particular, garages in the house strongly influence the indoor concentration of BTEX. Thus, the indoor BTEX level is significantly higher in winter than in summer. Moreover, garages with a connecting door to the living quarters lead to high indoor concentrations of aromatic hydrocarbons in these rooms. In addition, the storage of solvents and hobby materials, and also the presence of smoking guests increase the BTEX level. If rooms are directly heated by coal or wood, the BTEX level is higher compared to the use of gas heating. Surprisingly, no correlation was found between the building materials used and the BTEX level. Case studies were carried out for two homes with an integrated garage (and a connecting door to the living rooms) and for seven homes where redecoration work was carried out during sampling. In both instances, a pronounced increase was observed in the BTEX concentration.     

Lidar-assisted measurement of PM10 emissions from agricultural tilling in California's San Joaquin Valley – Part II: emission factors

Emission factors for agricultural operations are needed in order to develop reliable PM₁₀ emissions inventories and air quality models for air basins with significant agricultural land use. A framework was developed to analyze the PM₁₀ vertical profiles collected downwind of tilling operations in the San Joaquin Valley. The methods calculate emission factors on the basis of profile shape and assign quality ratings to each land preparation test. Uncertainties in the calculated emission factors and plume heights were used as one criterion for evaluating the relative quality of the reported emission factor. Other quality ratings were based on the magnitude of the difference in measured up- and downwind concentrations, wind direction, whether the tests were conducted near the edges of the field, and how well the proposed model fit the profile data. The emission factors from different operations were compared taking the quality of the emission factor into account. Plume heights and emission factors for 24 valid test profiles ranged from 2 to 20 m (mean=9.8; SD=3.6; median=9.8) and zero to 800 mg m⁻² (mean=152; SD=240; median=43), respectively. Key environmental properties governing PM₁₀ emission from these operations include relative humidity, soil moisture and vertical temperature gradient. Surprisingly, no discernable relationships were found between implement type or wind speed and the measured emission factors.     

Organochlorine compounds,nitro musks and perfluorinated substances in breast milk – Results from Bavarian Monitoring of Breast Milk 2007/8

The aim of the Bavarian Monitoring of Breast Milk (BAMBI) project was to examine 10 organochlorine pesticides (OPs), 3 nitro musks, 6 indicator polychlorinated biphenyls (PCBs), 7 polychlorinated dibenzo-p-dioxins (PCDDs), 10 polychlorinated dibenzofurans (PCDFs), 12 dioxin-like PCBs (dl-PCBs) and several perfluorinated alkyl compounds in breast milk samples. A total of 516 breast milk samples were collected from seven regions in Bavaria and were analyzed by means of GC/ECD, GC/HRMS, and LC/MS-MS.     

Wasser – elementare und strategische Ressource des 21. Jahrhunderts

Zusammenfassung   Hintergrund und Ziel Die steigende Nachfrage nach Sü?wasser bei begrenzten oder als Folge des Klimawandels regional zurückgehenden Wasserressourcen, verknüpft mit einer zunehmenden qualitativen Belastung, wirft immer h?ufiger die Frage auf, ob die Bev?lkerung einzelner Regionen, ganzer Kontinente oder gar der Erde in Zukunft mit einer Mangelsituation bezüglich verfügbarer Wasserressourcen konfrontiert sein wird. Diskussion Aufbauend auf einer Analyse der drei global relevanten Wasserkreisl?ufe (mariner, terrestrischer und Verbindungskreislauf ) werden die einwohnerspezifischen sich erneuernden Wasserressourcen der Kontinente quantitativ abgesch?tzt. Die aufgrund technisch-?konomischer Restriktionen zug?nglichen Wassermengen werden den menschlichen Nutzungsansprüchen gegenübergestellt und dabei die herausragende Bedeutung der Erzeugung von Biomasse (zur Verwendung als Nahrungsmittel, Futtermittel, Produktionsstoff oder Energietr?ger) im Hinblick auf den weltweiten Bedarf von Wasser dargestellt. Ergebnisse Im globalen Ma?stab besteht kein Wassermangel. Knappheiten treten regional oder saisonal auf. Ein Gro?teil des weltweit eingesetzten Wassers dient zur Erzeugung von Biomasse. Deshalb liegt in diesem Sektor ein wesentlicher Schlüssel zum strategischen Umgang mit Wasser. Die bisher übliche Bilanzierung von Wasserdargebot und -nachfrage übersieht oftmals auf der Dargebotsseite die Bedeutung des so genannten „grünen Wassers“ bei der Erzeugung von Biomasse und suggeriert deshalb Knappheiten, die de facto so nicht bestehen. Unserer Ansicht nach ist die Mengenangabe des sich j?hrlich global erneuernden Sü?wasservorkommens im Hinblick auf die gesamte menschliche Wassernutzung deutlich zu korrigieren. Die in der heutigen Literatur dominierende Angabe von etwa 40.000 km3 ist auf über 100.000 km3 anzuheben. Schlussfolgerungen und Perspektiven Wassermangel besteht weniger aus Gründen mangelnder Ressourcenverfügbarkeit oder aufgrund fehlender Technologien, sondern oftmals mangels Bewusstseins, fehlenden politischen Willens oder unzureichenden sozio-?konomischen Potenzialen. Aufgrund einer umfassenden Dargebots-Nachfrage-Bilanzierung, die alle Wassernutzungsformen integriert, sollten nationale und internationale Potenziale für die Bedarfsdeckung analysiert werden, um darauf aufbauend notwendige Versorgungsszenarien zu entwickeln.

Spatial variations in the aeolian deposition of dust – the effect of a city: a case study in Be'er-Sheva,Israel

The effect of buildings on the dry deposition of dust particles was investigated in Be'er-Sheva, a desert city with about 140,000 inhabitants in southern Israel, and at two reference points in the surrounding rural area. The mineral and chemical composition of dust sampled at all sites was similar, reflecting the composition of the local loess soil, its likely origin. However, dust deposited in the traps set up in the vicinity of buildings in the city was significantly coarser than the dust which accumulated in similar traps at exposed sites in the countryside. The amount of dust (by weight) in the urban dust traps was on an average more than twice the amount deposited in the rural area. The differences in grain-size distribution and quantity of dust are attributed to the properties of the urban wind field and to various effects of human activity in the city.     

The application of profluorescent nitroxides to detect reactive oxygen species derived from combustion-generated particulate matter: Cigarette smoke – A case study

Reactive oxygen species (ROS) and related free radicals are considered to be key factors underpinning the various adverse health effects associated with exposure to ambient particulate matter. Therefore, measurement of ROS is a crucial factor for assessing the potential toxicity of particles. In this work, a novel profluorescent nitroxide, BPEAnit, was investigated as a probe for detecting particle-derived ROS. BPEAnit has a very low fluorescence emission due to inherent quenching by the nitroxide group, but upon radical trapping or redox activity, a strong fluorescence is observed. BPEAnit was tested for detection of ROS present in mainstream and sidestream cigarette smoke. In the case of mainstream cigarette smoke, there was a linear increase in fluorescence intensity with an increasing number of cigarette puffs, equivalent to an average of 101 nmol ROS per cigarette based on the number of moles of the probe reacted. Sidestream cigarette smoke sampled from an environmental chamber exposed BPEAnit to much lower concentrations of particles, but still resulted in a clearly detectible increase in fluorescence intensity with sampling time. It was calculated that the amount of ROS was equivalent to 50 ± 2 nmol per mg of particulate matter; however, this value decreased with ageing of the particles in the chamber. Overall, BPEAnit was shown to provide a sensitive response related to the oxidative capacity of the particulate matter. These findings present a good basis for employing the new BPEAnit probe for the investigation of particle-related ROS generated from cigarette smoke as well as from other combustion sources.     

Biomonitoring of air quality in the Cologne Conurbation using pine needles as a passive sampler – Part III: Major and trace elements

We here report complementary trace element (Fe, Pb, Cd, Zn, Cr, Cu, Ni and sulfur) concentrations and ratios in pine needles collected in the urban area of Cologne, Germany. Potential element sources are discussed in conjunction with enviromagnetic and PAH data to evaluate air quality. Foliar trace element concentrations of Zn, Cr, Cu, Ni and sulfur are close to essential nutrient levels. Median concentrations of foliar Fe, Pb and Cd in Cologne are 132, 1.1, and 0.06 μg g^?1, respectively. Thus these elements are enhanced over biogenic background levels and show significant accumulation with needle exposure time. Foliar sulfur concentrations vary between 868 and 2076 μg g^?1 with a median value of 1409 μg g^?1, except for two locations where 2370 and 2379 μg g^?1 were observed. Cadmium serves as an indicator for local industrial emissions with short transport distances of only a few kilometres in Cologne City. Elevated Fe, Pb and Zn concentrations mark areas with higher traffic loads and agree with enhanced PAH burdens and magnetic susceptibility intensities of pine needles. Isopleths mapping and source differentiation of atmospheric pollutants using foliar trace elements is feasible. For temporal or spatial high-resolution studies more cost-effective environmental magnetics is recommended, which may guide in design of detailed studies aiming at identification and allocation of emission sources. Hereby, a combination of organic tracers (PAH), magnetic properties, and trace metals is considered most reliable.