The first reference gas mixtures of sulfur-free natural gas odorants that are traceable to the International System of Units (SI) have been produced and their compositions validated. These mixtures, which contain methyl acrylate and ethyl acrylate at amount fractions between 1.1 and 2.1 μmol mol-1, can be used to underpin measurements of sulfur-free odorants, which are increasingly being used to odorize natural gas in transmission networks as they have less harmful properties than traditional sulfur-containing odorants. The reference gas mixtures produced have been shown to be stable in passivated aluminum cylinders for at least 8 months and have been validated (to within 6% or less) by interlaboratory measurements at three National Measurement Institutes. The stability of methyl acrylate and ethyl acrylate in gas sampling bags has been investigated, and the challenges of analyzing 2-ethyl-3- methylpyrazine, which is used as a stabilizer in sulfur-free odorants, are also briefly discussed.

Objectives. The aim of this study was to evaluate the bone tissue response to fiber-reinforced composite (FRC) in comparison with titanium (Ti) implants after 12 weeks of implantation in cancellous bone using histomorphometric and ultrastructural analysis. Materials and methods. Thirty grit-blasted cylindrical FRC implants with BisGMA-TEGDMA polymer matrix were fabricated and divided into three groups: (1) 60 s light-cured FRC (FRC-L group), (2) 24 h polymerized FRC (FRC group), and (3) bioactive glass FRC (FRC-BAG group). Titanium implants were used as a control group. The surface analyses were performed with scanning electron microscopy and 3D SEM. The bone-implant contact (BIC) and bone area (BA) were determined using histomorphometry and SEM. Transmission electron microscopy (TEM) was performed on Focused Ion Beam prepared samples of the intact bone-implant interface. Results. The FRC, FRC-BAG and Ti implants were integrated into host bone. In contrast, FRC-L implants had a consistent fibrous capsule around the circumference of the entire implant separating the implant from direct bone contact. The highest values of BIC were obtained with FRC-BAG (58 ± 11%) and Ti implants (54 ± 13%), followed by FRC implants (48 ± 10%), but no significant differences in BIC or BA were observed (p = 0.07, p = 0.06, respectively). TEM images showed a direct contact between nanocrystalline hydroxyapatite of bone andboth FRC and FRC-BAG surfaces. Conclusion. Fiber-reinforced composite implants are capable of establishing a close bone contact comparable with the osseointegration of titanium implants having similar surface roughness.

Detailed quantitative characterization of the combustion gases from a series of room fires is reported in this article. Three simulated room fires were conducted with a test room containing a typical domestic fuel load of furniture including a TV-set. Two types of TV-sets were studied in the experiments, i.e. those containing fire retarded and non-fire retarded enclosure material. The measurement of the combustion gases included inorganic species and various organic species among them polychlorinated and polybrominated dibenzodioxins and furans, and selected brominated flame retardant agents. The detailed quantitative characterization of the combustion gases from the room fires forms a unique source of emission data for fire incidents in buildings. Chlorinated dibenzodioxins and furans were found in the combustion gases from all room tests. No brominated dioxins were found, however brominated furans were found. Further, the results from the room tests indicate that a TV-set treated with brominated flame retardants included in the fire load of a room fire does not necessarily increase the emission of bromine containing organic combustion products. The methodology applied for the sampling and analysis has been described in Part I of this series of articles.

The accurate quantification of low-concentration sulfur-containing compounds is essential for the biogas and natural gas industries. We review literature data for the stability of these compounds in standard gas mixtures when sampled in cylinders with different passivations, sample bags, sorbent tubes, solid-phase microextraction and glass sampling bulbs, and we present new data obtained at our three National Measurement Institutes. We show that losses of sulfur-containing compounds are minimized when using passivated sampling cylinders, and the most suitable sorbent material for sampling these compounds is Tenax TA. We also discuss methods for transferring gas from sample vessels to analyzers and give recommendations for the selection of regulators (and other pressure-reducing devices) and transfer lines. Further, we propose approaches that could be taken to reduce or correct for losses in order to provide more accurate measurements of sulfur-containing compounds.

Phthalate esters are among the most ubiquitous of indoor pollutants and have been associated with various adverse health effects. In the present study we assessed the cross-sectional association between eight different phthalate metabolites in urine and allergic disease in young children. As part of the Danish Indoor Environment and Children's Health study, urine samples were collected from 440 children aged 3-5 years, of whom 222 were healthy controls, 68 were clinically diagnosed with asthma, 76 with rhinoconjunctivitis and 81 with atopic dermatitis (disease subgroups are not mutually exclusive; some children had more than one disease). There were no statistically significant differences in the urine concentrations of phthalate metabolites between cases and healthy controls with the exception of MnBP and MECPP, which were higher in healthy controls compared with the asthma case group. In the crude analysis MnBP and MiBP were negatively associated with asthma. In the analysis adjusted for multiple factors, only a weak positive association between MEP in urine and atopic dermatitis was found; there were no positive associations between any phthalate metabolites in urine and either asthma or rhinoconjunctivitis. These findings appear to contradict earlier studies. Differences may be due to higher exposures to certain phthalates (e.g., BBzP) via non-dietary pathways in earlier studies, phthalates serving as surrogates for an agent associated with asthma (e.g., PVC flooring) in previous studies but not the present study or altered cleaning habits and the use of "allergy friendly" products by parents of children with allergic disease in the current study in contrast to studies conducted earlier.

Flux of Organic Compounds from Grass measured by Relaxed Eddy Accumulation Technique.

Det antas ibland att byggmaterial genom sitt innehåll av kemiska ämnen påverkar omgivande miljö. Rapporten inleds därför med en internationell översikt av praktikfall där kemiska ämnen, huvudsakligen genom utlakning, har avgivits kring byggnader och anläggningar. Antalet tekniskt väldokumenterade typfall där ämnen har avgivits till miljön kring en byggnad eller anläggning är få. Det finns dock ett stort antal laboratorieundersökningar som visar på byggmaterials potential för att avge ämnen till den yttre miljön. Det har därvid visat sig att innehållet av kemiska ämnen ofta inte har något direkt samband med materialets faktiska miljöpåverkan. Avvecklingslistor för kemiska ämnen som används vid upphandling av byggmaterial bör därför användas med viss eftertänksamhet. I avsnitt om metaller, polymera material respektive betong och andra cementbunda material samt i substansinriktade avsnitt om PAH, flamskyddsmedel, träskyddsmedel och andra biocider kommenteras de olika praktikfallen och laboratorieundersökningarna. Potentialen för avgivning till närmiljön är en hörnsten i EGs regelverk för byggprodukter. Rapporten behandlar därför direktivet om byggprodukter [1989/106/EEG] med inriktning på CE-märkning och det anslutande pågående arbetet med att utveckla standarder för bl a utlakning av reglerade ämnen. En översikt ges också av den europagemensamma kemikalielagstiftningen med inriktning på riskbedömning av byggprodukter. Rapporten behandlar även nationella notifierade tyska och främst nederländska bestämmelser vilka detaljerat beaktar miljöaspekter för byggmaterial samt olika slag av restprodukter som främst kan användas i vägar och annat anläggningsbyggande. Sådana nationella regler saknas i Sverige. Med utgångspunkt från officiella regelverk och frivilliga kvalificerade miljömärkningsordningar har en översiktlig och riskorienterad värderingsmall för inledande miljöbedömning av utvändiga byggmaterial utarbetats. Rapporten riktar sig till tillverkare, projektörer, arkitekter, inköpare, handläggare vid miljöförvaltningar och miljöansvariga inom bygg- och anläggningssektorn. Rapporten innehåller 190 litteraturreferenser samt hänvisningar till ett stort antal EG-direktiv och internationella standarder med anknytning till området byggmaterial och miljö. 116 sidor.

Kinetics of the gas-phase reaction of n-C6-C10 aldehydes with the nitrate radical

The flux of isoprene from a willow coppice plantation and the effect on the local air quality”, Atmospheric Environment, 39(11), 2061-2070, 2005.

Around the world humans use products that contain phthalates, and human exposure to certain of these phthalates has been associated with various adverse health effects. The aim of the present study has been to determine the concentrations of the metabolites of diethyl phthalate (DEP), di(n-butyl) phthalate (DnBP), di(iso-butyl) phthalate (DiBP), butyl benzyl phthalate (BBzP) and di(2-ethylhexyl) phthalate (DEHP) in urine samples from 441 Danish children (3-6 years old). These children were subjects in the Danish Indoor Environment and Children's Health study. As part of each child's medical examination, a sample from his or her first morning urination was collected. These samples were subsequently analyzed for metabolites of the targeted phthalates. The measured concentrations of each metabolite were approximately log-normally distributed, and the metabolite concentrations significantly correlated with one another. Additionally, the mass fractions of DEP, DnBP, DiBP and BBzP in dust collected from the children's bedrooms and daycare centers significantly correlated with the concentrations of these phthalates' metabolites (monoethyl phthalate (MEP), mono-n-butyl phthalate (MnBP), mono-isobutyl phthalate (MiBP) and monobenzyl phthalate (MBzP), respectively) in the children's urine. Such correlations indicate that indoor exposures meaningfully contributed to the Danish children's intake of DEP, DnBP, DiBP and BBzP. This was not the case for DEHP. The urine concentrations of the phthalate metabolites measured in the present study were remarkably similar to those measured in urine samples from children living in countries distributed over four continents. These similarities reflect the globalization of children's exposure to phthalate containing products.