Results of the First EC/OC Comparison Exercise for EU National Air Quality Reference Laboratories (AQUILA)

The JRC-IES European Reference Laboratory for Air Pollution (ERLAP) has organized an inter-laboratory comparison for the measurement of elemental carbon (EC) and organic carbon (OC) in particulate matter sampled on filters. To this comparison European Union National Reference Laboratories for air quality or delegated organizations have participated, all using instrumentation of the same make (Sunset Laboratories Inc. ). The objectives of this comparison have been to evaluate the performances of participants but also to study the effects of the use of different thermal analysis protocols currently used for analysis. It has been shown – based on z-scores – that all participants using laboratory analyzers are able to meet a 25% expanded uncertainty as a “fitness-for-purpose” criterion for total carbon (TC, as the sum of OC and EC) and OC. For EC this criterion is only met when results are evaluated by specific protocols (NIOSH or EUSAAR_2) separately. Field versions of the analyzer have been found for a number of samples to yield aberrant results.JRC.H.2-Air and Climat

Literature review on the performance of diffusive samplers for the measurement of ammonia in ambient air and emissions to air

The information in this document has formed the basis from which a new standard on measurements employing ammonia diffusive samplers by CEN TC264 WG11 'Ambient air - Diffusive samplers' is being developed and provides an open reference document for the ammonia passive sampling techniques

Feasibility Study of Preparation and Certification of Reference Materials for Nitrogen Dioxide and Sulfur Dioxide in Diffusive Samplers

Feasibility study of preparation and certification of reference materials for nitrogen dioxide and sulfur dioxide in diffusive samplers Michel Gerboles*, Daniela Buzica, Luciano Amantini, Friedrich Lagler and Theo Hafkenscheid+ European Commission - Joint Research Centre, Institute for Environment and Sustainability, Emissions and Health Unit, 21020 Ispra, Italy. Fax: +39-332-785652; Tel: +39-332-789364; E-mail: [email protected] +Dutch Measurement Institute, Delft, Netherlands This paper presents the results of a feasability study for the preparation and certification of reference materials (RMs) for nitrogen dioxide (NO2) and sulphur dioxide (SO2) in diffusive samplers. RMs for NO2 were prepared by exposure to gas mixtures in a chamber while the RMs for SO2 were prepared by liquid spiking. Certification of RMs for NO2 was found feasible with a certified uncertainty of 5.8 % and a proposed shelf life of 5 years. The uncertainty was calculated with contribution from the homogeneity of preparation, stability and transport of the CRMs and from an external verification of the certified value. To reach 5.8 % of uncertainty, the contribution of the differences between the results of analysis by ion chromatography and colorimetry must be eliminated. It is proposed to solve this by pre-extracting the samplers with water before analysis. The results of this study indicate that the samplers are stable for at least two years before and after exposure when stored in refrigerator. On the opposite, the certification of RMs for SO2 was found not feasible due to instability problems. This instability was attributed to reaction of sulfate on the walls of the samplers. Alternatively, the preparation of RMs by simultaneous exposure to SO2 and NO2 have been tested. Satisfying homogeneities has been reached both for NO2 and SO2.JRC.H.4-Transport and air qualit

The Emerging Importance of IgG Fab Glycosylation in Immunity

Human IgG is the most abundant glycoprotein in serum and is crucial for protective immunity. In addition to conserved IgG Fc glycans, ∼15-25% of serum IgG contains glycans within the variable domains. These so-called "Fab glycans" are primarily highly processed complex-type biantennary N-glycans linked to N-glycosylation sites that emerge during somatic hypermutation. Specific patterns of Fab glycosylation are concurrent with physiological and pathological conditions, such as pregnancy and rheumatoid arthritis. With respect to function, Fab glycosylation can significantly affect stability, half-life, and binding characteristics of Abs and BCRs. Moreover, Fab glycans are associated with the anti-inflammatory activity of IVIgs. Consequently, IgG Fab glycosylation appears to be an important, yet poorly understood, process that modulates immunit

A Technical Review of the Feasibility of Producing Certified Reference Materials for the Measurement of Gaseous Pollutants in Ambient Air

Within the frame of the EU sponsoredproject ‘Cermatair’ (CertifiedReference Materials for the Measurement of Gaseous Pollutants in Ambient Air, contract G6RD-CT-2001-00517) the feasibility of preparing andcertifying reference materials for the measurement of sulphur dioxide, nitrogen dioxide, carbon monoxide and benzene in ambient air was studied. The project focused on measurements at concentration levels corresponding to limit values given in EU Ambient Air Quality Directives andcovered reference materials for the reference methods specifiedin these Directives and for alternative methods based on diffusive sampling. State-of-the-art technologies for the production and certification of the reference materials were identified through literature surveys. Limited batches of reference materials were preparedand , wherever appropriate, testedfor homogeneity. The reference materials were subsequently tested in small-scale external verifications, performedby 2–4 laboratories other than the preparation laboratory, aimedat identifying possible discrepancies between concentration values from the preparation processes and experimental values. The results of these verifications revealedpossible mechanisms of certification (basedon preparation or measurements). The remaining materials were subjectedto a one-year stability study.JRC.H.4-Transport and air qualit

Review of the Application of Diffusive Samplers for the Measurement of Nitrogen Dioxide in Ambient Air in the European Union

A number of diffusive samplers that are used for longer-term monitoring of nitrogen dioxide in the European Union were subjected to a review of their use and performance characteristics. The information collected was used to evaluate the capacity of diffusive samplers for monitoring the European Union annual limit value of 40 µg.m-3 and to draft a proposal method for monitoring nitrogen dioxide in ambient air using diffusive samplers for later standardisation by the CEN Technical Committee 264 ¿Air Quality¿ Working Group 11 ¿Diffusive Samplers¿. A bibliographic review was carried out to determine the availability of validation data for these samplers, their capacity to meet the data quality objectives for indicative and/or fixed measurements of the European Directive, the possibility for users to analyse the samplers and their current use throughout the European Union for measuring ambient air quality. Two tubes-type samplers and a radial sampler were found to be used throughout the European Union. Based on the findings of the review it was concluded only for tube-type samplers based on the application of triethanolamine as the sorbent sufficient information was available to underpin its potential for meeting European Union data quality objectives, at the least, for indicative measurements of nitrogen dioxide in ambient air.JRC.H.4-Transport and air qualit

Different collector types for sampling deposition of polycyclic aromatic hydrocarbons - comparison of measurement results and their uncertainty

International audienceDifferent collector types, sample workup procedures and analysis methods to measure the deposition of polycyclic aromatic hydrocarbons (PAH) were tested and compared. Whilst sample workup and analysis methods did not influence the results of PAH deposition measurements, using different collector types changed the measured deposition rates of PAH significantly. The results obtained with a funnel-bottle collector showed the highest deposition rates and a low measurement uncertainty. The deposition rates obtained with the wet-only collectors were the lowest at industrial sites and under dry weather conditions. For the open-jar collectors the measurement uncertainty was high. Only at an industrial site with extremely high PAH deposition rates the results of open-jar collectors were comparable to those obtained with funnel-bottle collectors. Thus, if bulk deposition of PAH has to be measured, funnel-bottle combinations are proved to be the collectors of choice. These collectors were the only ones always fulfilling the requirements of European legislation

The extensive glycosylation of the ACPA variable domain observed for ACPA-IgG is absent from ACPA-IgM

Transplantation and autoimmunit

Adaptive antibody diversification through-linked glycosylation of the immunoglobulin variable region

A hallmark of B-cell immunity is the generation of a diverse repertoire of antibodies from a limited set of germline V(D)J genes. This repertoire is usually defined in terms of amino acid composition. However, variable domains may also acquire-linked glycans, a process conditional on the introduction of consensus amino acid motifs (-glycosylation sites) during somatic hypermutation. High levels of variable domain glycans have been associated with autoantibodies in rheumatoid arthritis, as well as certain follicular lymphomas. However, the role of these glycans in the humoral immune response remains poorly understood. Interestingly, studies have reported both positive and negative effects on antibody affinity. Our aim was to elucidate the role of variable domain glycans during antigen-specific antibody responses. By analyzing B-cell repertoires by next-generation sequencing, we demonstrate that-glycosylation sites are introduced at positions in which glycans can affect antigen binding as a result of a specific clustering of progenitor glycosylation sites in the germline sequences of variable domain genes. By analyzing multiple human monoclonal and polyclonal (auto)antibody responses, we subsequently show that this process is subject to selection during antigen-specific antibody responses, skewed toward IgG4, and positively contributes to antigen binding. Together, these results highlight a physiological role for variable domain glycosylation as an additional layer of antibody diversification that modulates antigen binding.status: publishe