Results of the baseline assessment for NSL monitoring

Om de luchtkwaliteit in Nederland te verbeteren is het Nationaal Samenwerkingsprogramma Luchtkwaliteit (NSL) opgezet. In dit programma werken de Rijksoverheid en decentrale overheden samen om te zorgen dat Nederland overal tijdig aan de grenswaarden voor fijnstof en stikstofdioxide zal voldoen. Bij het NSL is ook een monitoringsprogramma opgezet om het bereiken van dit doel te waarborgen. Belangrijk onderdeel hiervan is een informatie- en rekensysteem (Monitoringtool) dat met een jaarlijks actualisatieproces het halen van de grenswaarden inzichtelijk moet maken. Voorafgaand aan de start van de monitoring heeft het RIVM een analyse (nulmeting) van dit systeem uitgevoerd. Vooral vanwege de consistente aanpak heeft de Monitoringtool veel potentie. Desondanks liggen er nog belangrijke verbeterpunten om het daadwerkelijk een robuust systeem te maken. Ondanks de consistente aanpak hebben de berekeningen voor toekomstige jaren een relatief grote onzekerheid, vooral doordat de kwaliteit van de invoergegevens niet bekend is. De kwaliteit van deze locatiespecifieke invoergegevens is primair de verantwoordelijkheid van lokale overheden die deze aanleveren. Thans zijn niet alle relevante onderbouwingen van deze gegevens in het monitoringstraject beschikbaar. Hierdoor is het moeilijk om de kwaliteit van deze gegevens en de daarop gebaseerde rekenresultaten te beoordelen. Met de nu voorliggende combinatie van de Monitoringstool en de bijbehorende invoergegevens kan het RIVM de kwaliteit van de monitoringsresultaten niet objectief vaststellen. Als gevolg hiervan kunnen in de monitoring van het NSL geen conclusies aan deze resultaten worden verbonden. In dit rapport worden aanbevelingen gedaan om de kwaliteit van de invoergegevens te vergroten en daarmee de onzekerheid van het eindresultaat te verkleinen. Bij het opstellen van de eerste Monitoringrapportage wordt in meer detail naar de kwaliteit van de resultaten van de Monitoring worden gekeken. De Monitoringtool vormt een belangrijke invulling van het Aarhus protocol waarin toegang van burgers tot milieugegevens wordt geregeld. Het rekeninstrument dat de kern vormt van het monitoringsprogramma is onder grote tijdsdruk tot stand gekomen en is deels nog in ontwikkeling. Het RIVM kan daardoor op dit moment alleen concluderen dat de gebruikte rekenmethoden voldoen aan de technisch-inhoudelijk en wettelijke regels om de luchtkwaliteit te berekenen. Het goed werken van het gehele rekeninstrument (inclusief volledige database en website) kon slechts beperkt worden getest. Een algemene uitspraak hierover, en dus ook over de kwaliteit van de monitoringsresultaten, is in deze nulmeting dan ook niet mogelijk.In order to improve the air quality in the Netherlands, the Ministry of Spatial Planning and the Environment (VROM) has authorised the establishment of The National Air Quality Cooperation Programme (NSL). Within the framework of this programme, the central government and local and regional authorities are collaborating to ensure that the Netherlands achieves timely compliance throughout the entire country with the limit values for particulate matter and nitrogen dioxide. The NSL includes a monitoring programme to ensure that this objective is achieved. One important part of this programme is an information and calculation system - i.e., a monitoring tool - that aims to guarantee compliance with the limit values through a yearly process of actualisation. The National Institute for Public Health and the Environment (RIVM) has performed a baseline assessment of this system prior to the start of monitoring. Due specifically to the consistency of its approach, the monitoring tool has great potential. However, there remain a number of important points for improvement before it will be a truly robust system. Despite the consistency of the approach, the prognostic calculations show a relatively high degree of uncertainty - mainly because the quality of the input data is unknown. The quality of the locality-specific input data is primarily the responsibility of local authorities, which provide the information. At the present time, these data are not subjected to further substantiation in the monitoring programme and, consequently, it is difficult to assess the quality of both the data and the calculated concentrations that are based on these data. Given the current limitations of this combination of monitoring tool and input data, it is not possible to draw any conclusion to the monitoring results. This report contains recommendations on how to improve the quality of the input data and thereby reduce the uncertainty of the end result. The quality of the monitoring results will be examined in more detail during the drafting of the first Monitoring Report. The monitoring tool constitutes an important supplement to the Aarhus protocol which ratifies public access to environmental information within the EU. The calculation instrument that forms the core of the monitoring programme was developed under great time pressure, and parts of it are still in the development stage. Therefore, at the present time, the only conclusion that can be drawn by the RIVM is that the calculation methods used satisfy the technical and statutory regulations for calculating air quality. It is not yet possible to comprehensively test whether the entire system (including the complete database and website) performs correctly. Consequently, it is also not possible to make a general pronouncement on either the system or the quality of the monitoring results in this baseline assessment.VRO

H.G. Stoker as student - die wysgerige denkklimaat en akademiese wisselwerking met Scheler en Buytendijk

This article represents an indispensable part of the total corpus of this issue. It contains a transcription of the letters of H.G. Stoker to F.J.J. Buytendijk, annotated by Arnold Beijk and further illuminated and commented on by Theo van der Merwe. This kind of archival material is of immense value in developing a comprehensive vision and overview of H.G. Stoker’s work not only for the more casual reader, but more particularly for the serious scholar who can find solid academic support in these documents for assumptions made about Stoker's work. Stoker’s creative and illuminating personal style of thinking and writing is well demonstrated here. The letters reveal very strikingly the course o f the academic interaction between Stoker and Buytendijk about his study on conscience which he was conducting under the guidance of Max Scheler. The material also provides fascinating incidental material about Stoker's vision of the country and its universities, more particularly the University of Potchefstroom, at the time. His perspective on his own academic ideals comes out well and ties in with considerations drawn from the European milieu

Progress of the National Air Quality Cooperation Programme (NSL)

Om de luchtkwaliteit in Nederland te verbeteren is het Nationaal Samenwerkingsprogramma Luchtkwaliteit (NSL) opgezet. In dit programma werken de Rijksoverheid en decentrale overheden samen om te zorgen dat Nederland overal tijdig aan de grenswaarden voor fijnstof (2011) en stikstofdioxide (2015) zal voldoen. Om de voortgang te volgen is bij het NSL een monitoringsprogramma opgezet. Centraal onderdeel daarvan is een rekeninstrument waarvoor de overheden de brongegevens aanleveren. De daaruitvolgende rekenresultaten zijn vervolgens door het Bureau Monitoring (samenwerkingsverband RIVM en InfoMil) samengevoegd in voorliggende voortgangsrapportage. De prognoses voor 2011 en 2015 laten zien dat voor een groot deel van Nederland de resultaten onder de Europese grenswaarden voor PM10 (fijnstof) en NO2 liggen. Op een aantal plekken zijn er wel nieuwe of grotere overschrijdingen van de PM10- en NO2-grenswaarden zichtbaar. Bij de fijnstof (PM10) overschrijdingen gaat het hoofdzakelijk om locaties bij veehouderijen en een aantal industriele gebieden. Vooral nabij veehouderijen is op een aantal plekken nog sprake van grote overschrijdingen die lastig voor medio 2011 op te lossen zijn. De huidige prognose voor de concentraties stikstofdioxide in 2015 laat een minder gunstige ontwikkeling zien ten opzichte van wat is berekend in de vaststelling van het NSL. Dit komt voor een belangrijk deel door tegenvallende verkeersemissies wat heeft geleid tot een aantal nieuwe overschrijdingen. De nu in de prognoses berekende concentraties liggen op veel locaties net onder de grenswaarde. Met veel concentraties net onder de grenswaarde neemt het aantal overschrijdingen snel toe bij een tegenvaller in een van de gemaakte aannamen. In combinatie met een grote en deels onbekende onzekerheid in de rekenresultaten vormt dit een risico voor het behalen van de doelstelling van het NSL.The NSL has been put in place to improve air quality in the Netherlands and to ensure that the Netherlands meets the date of compliance with the EU limit values for particulate matter and nitrogen dioxide. Local, regional and national authorities work together within the framework of this programme to ensure that these goals are met. A monitoring programme, centred around a specially designed assessment tool, has been set up to monitor the progress. This tool uses data that the participating authorities are required to provide as part of the annual monitoring cycle. The results of the tool have been bundled by the Bureau Monitoring into this progress report. The prognosis for 2011 and 2015, based on the results obtained using the assessment tool, are that the concentrations of PM10 and NO2 fall below the EU limit values in most parts of the Netherlands. However, exceedances of the limit values do occur at specific locations. For PM10, these exceedances mostly occur close to a number of industrial sites and stock farms. Particularly high exceedances in the vicinity of these stock farms will make it difficult to meet the limit values by mid 2011 at these locations. The prognostications for NO2 show a less favourable decline in NO2 concentrations than was modelled at the establishment of the NSL. This is mostly due to the decline in traffic emissions falling short of expectations, resulting in new exceedances. At many locations, the calculated concentrations in the prognostications fall just under the limit value and, consequently, there will be a large increase in the number of exceedances when one or more of the premises become less favourable. This possibility, together with the large and partially unknown uncertainty in the calculation results, add up to a risk for not meeting the limit values by the date of compliance.VRO

The suitability of a seasonal ensemble hybrid framework including data-driven approaches for hydrological forecasting

Hydrological forecasts are important for operational water management and near-future planning, even more so in light of the increased occurrences of extreme events such as floods and droughts. Having a forecasting framework, which is flexible in terms of input forcings and forecasting locations (local, regional, or national) that can deliver this information in fast and computational efficient manner, is critical. In this study, the suitability of a hybrid forecasting framework, combining data-driven approaches and seasonal (re)forecasting information from dynamical models, to predict hydrological variables was explored. Target variables include discharge and surface water levels for various stations at a national scale, with the Netherlands as the focus. Five different machine learning (ML) models, ranging from simple to more complex and trained on historical observations of discharge, precipitation, evaporation, and seawater levels, were run with seasonal (re)forecast data, including the European Flood Awareness System (EFAS) and ECMWF seasonal forecast system (SEAS5), of these driver variables in a hindcast setting. The results were evaluated using the evaluation metrics, i.e. anomaly correlation coefficient (ACC), continuous ranked probability (skill) score (CRPS and CRPSS), and Brier skill score (BSS), in comparison to a climatological reference hindcast. Aggregating the results of all stations and ML models revealed that the hindcasting framework outperformed the climatological reference forecasts by roughly 60g% for discharge predictions (80g% for surface water level predictions). Skilful prediction for the first lead month, independently of the initialization month, can be made for discharge. The skill extends up to 2-3 months for spring months due to snowmelt dynamic captured in the training phase of the model. Surface water level hindcasts showed similar skill and skilful lead times. While the different ML models showed differences in performance during a testing and training phase using historical observations, running the ML framework in a hindcast setting showed only minor differences between the models, which is attributed to the uncertainty in seasonal forecasts. However, despite being trained on historical observations, the hybrid framework used in this study shows similar skilful predictions to previous large-scale forecasting systems. With our study, we show that a hybrid framework is able to bring location-specific skilful seasonal forecast information with global seasonal forecast inputs. At the same time, our hybrid approach is flexible and fast, and as such, a hybrid framework could be adapted to make it even more interesting to water managers and their needs, for instance, as part of a fast model-predictive control framework

Adsorption of titanium dioxide nanoparticles onto zebrafish eggs affects colonizing microbiota

Teleost fish embryos are protected by two acellular membranes against particulate pollutants that are present in the water column. These membranes provide an effective barrier preventing particle uptake. In this study, we tested the hypothesis that the adsorption of antimicrobial titanium dioxide nanoparticles onto zebrafish eggs nevertheless harms the developing embryo by disturbing early microbial colonization. Zebrafish eggs were exposed during their first day of development to 2, 5 and 10 mg TiO2 L-1 (NM-105). Additionally, eggs were exposed to gold nanorods to assess the effectiveness of the eggs' membranes in preventing particle uptake, localizing these particles by way of two-photon microscopy. This confirmed that particles accumulate onto zebrafish eggs, without any detectable amounts of particles crossing the protective membranes. By way of particle-induced X-ray emission analysis, we inferred that the titanium dioxide particles could cover 25-45 % of the zebrafish egg surface, where the concentrations of sorbed titanium correlated positively with concentrations of potassium and correlated negatively with concentrations of silicon. A combination of imaging and culture-based microbial identification techniques revealed that the adsorbed particles exerted antimicrobial effects, but resulted in an overall increase of microbial abundance, without any change in heterotrophic microbial activity, as inferred based on carbon substrate utilization. This effect persisted upon hatching, since larvae from particle-exposed eggs still comprised higher microbial abundance than larvae that hatched from control eggs. Notably, pathogenic aeromonads tolerated the antimicrobial properties of the nanoparticles. Overall, our results show that the adsorption of suspended antimicrobial nanoparticles on aquatic eggs can have cascading effects across different life stages of oviparous animals. Our study furthermore suggests that aggregation dynamics may occur that could facilitate the dispersal of pathogenic bacteria through aquatic ecosystems