Processes of air pollutant transport and transformation at the urban scale are in general more complex than at larger scales: Buildings and other obstructions lead to complex wind flow patterns in an urban area, while the presence of large concentration gradients within cities makes it extremely difficult to find representative locations for air quality monitoring stations. Additional difficulties may arise from the typical intermittency of air pollutant concentrations in an urban area and from the strong impact that concentration fluctuations may have with regard to chemical reactions occuring in an urban airshed. Addressing these issues is vital for solving major air pollution problems in Europe.
The goal of SATURN is, in line with EUROTRAC-2, to lead to a better understanding of urban air pollution as a prerequisite for finding effective solutions to air quality problems and for a sustainable development in the urban environment. For this purpose, the main scientific objective of this subproject is to substantially improve our ability of establishing source-receptor relationships at the urban scale. Ensuring the validity of such relationships may also facilitate assessing the impact of urban areas to regional and global scale problems of the atmospheric environment.
To meet this objective, the following methodology will be followed within SATURN:
In accordance with the above objective, SATURN aims at achieving scientific innovation in all fields pertinent to the urban air pollution problem. Specifically:
1 Steering Group
Nicolas Moussiopoulos, Thessaloniki, Greece (Subproject Coordinator)
K. Dick van den Hout, Apeldoorn, The Netherlands (Deputy Coordinator)
Patrice Mestayer, Nantes, France (Deputy Coordinator)
Finn Palmgren, Roskilde, Denmark (Deputy Coordinator)
Michael Schatzmann, Hamburg, Germany (Deputy Coordinator)
Roel van Aalst, Bilthoven, The Netherlands
Ivo Allegrini, Rome, Italy
Jose M. Baldasano, Barcelona, Spain
Carlos Borrego, Aveiro, Portugal
Laszlo Bozó, Budapest, Hungary
Rex Britter, Cambridge, United Kingdom
Giovanni Graziani, JRC Ispra, EC
Steinar Larssen, Kjeller, Norway
Rudolph Pischinger, Graz, Austria
2 Principal Investigators
3 Aim of the subproject
The aim of SATURN is to substantially improve our ability of establishing source-receptor relationships at the urban scale. To meet this aim, the following sequence of activities is planned:
4 Project description
In the past years much scientific knowledge on air pollution has been built up, to a large extent in the frame of EUROTRAC. As a result, there are now many national emission data bases and model systems that, at least partially, suit the environmental management needs of national and international authorities . The level of aggregation of these data and systems tends, however, to be too high for addressing urban air quality issues.
Tools supporting environmental management are also available for calculating air quality near individual sources. Short range dispersion models represent the only category for which activities towards model harmonisation have already taken place in Europe .
On the contrary, at the urban scale air quality management tools are lacking and this in spite of the fact that the majority of the population lives in cities. This is one of the main results from a recent survey carried out in several European countries by COST action 615 "Database, monitoring and modelling of urban air pollution" . Indeed, concerns on the health effects of air pollution have recently become more urgent. Despite the achievements in emission reductions, in most European cities short-term WHO air quality guidelines are still exceeded . Since the urban authorities have limited competence regarding measures to reduce emissions, also authorities at the regional, national and international level are interested in urban air quality management matters.
Apart from the apparent potential for policy applications (see also section 4.3), devoting special attention to the urban scale is important also from the scientific point of view:
4.2 Objective of SATURN
The goal of SATURN is, in line with that of EUROTRAC-2, to reach a better understanding of urban air pollution as a prerequisite for finding effective solutions to air quality problems and for a sustainable development in the urban environment. For this purpose, the main scientific objective of this subproject is to substantially improve our ability of establishing source-receptor relationships at the urban scale. Ensuring the validity of such relationships may also facilitate assessing the impact of urban areas to regional and global scale problems of the atmospheric environment.
To meet this objective, the following methodology will be followed within SATURN:
From the above it is apparent that work in SATURN will significantly contribute to achieving several scientific aims of EUROTRAC-2. Specifically, scientific work in SATURN is relevant to the project tasks 1a/b, 2a/b/d, 3a/b, 5a/b/c and 7a/b/c/d/e.
4.3 Potential policy applications of SATURN results
SATURN will contribute to improved urban air quality management by providing novel systems for a comprehensive overview of source-receptor relationships both for peak and city background levels of air pollution. In spite of their small spatial extent (e.g., a few meters from traffic), peaks are important because they give the largests problems and also exceed limit values most. City background levels, on the other hand, are associated with the exposure of the general population in the city. From the modelling side, covering both peak and city background levels can only be accomplished by coupling urban scale and microscale models. From the view of measuring concentrations, this implies that measurements need to account for so-called 'hot spots', as well as to allow extrapolating to general patterns in the city by the aid of suitable models.
Once the spatial and temporal distribution of air pollution is known, urban authorities need to have insight in the causes of air pollution and in the possibilities to reduce the levels or to control anticipated increases of levels. In SATURN methods to determine the contributions of sources will be developed and improved. Also, methods to simulate the effect of long-term emission changes will be improved as the basis for formulating and evaluating reasonable air pollution abatement strategies. Finally, novel systems for the prediction of smog episodes are also among the deliverables of SATURN.
4.4 Scientific aims of SATURN
(a) Model development
The main deliverable of SATURN will be a set of properly validated urban air pollution models. For this purpose, new modelling tools will be developed and existing ones will be refined. Activities are planned at all relevant scales, i.e., from the microscale up to the local-to-regional scale. It is envisaged to formulate new comprehensive urban air pollution model systems as well as novel subgrid models and chemical modules. Most of the new developments will be evaluated during validation or intercomparison exercises foreseen in SATURN. Moreover, they will be used for the analysis of physical and chemical processes to be studied in the frame of SATURN.
Substantial scientific progress is expected from modelling activities in SATURN:
(b) Model evaluation
The scientific basis for evaluating urban air pollution models will be improved by establishing appropriate evaluation procedures. It is anticipated that most progress will be achieved concerning the evaluation of prognostic wind models and, secondarily, dispersion models for inert pollutants. Depending on the quality of experimental data to be gathered in the frame of EUROTRAC-2, relevant approaches will be developed also for specific classes of urban scale chemistry-and-transport models. Moreover, detailed specifications will be formulated for all data involved in evaluation procedures in order to avoid that model evaluation attempts fail because of missing or inadequate data.
Detailed scientific aims regarding model evaluation include:
Model evaluation will be primarily based on new comprehensive datasets which are expected to result from urban scale field campaigns (proposed in SATURN or other EUROTRAC-2 subprojects). Hence, SATURN will add much value to experiments presently being performed or proposed in various European cities. Supplementary experimental studies are planned in SATURN for analysing important urban scale physical and chemical processes, including those occuring within the canopy layer. Results of such studies will lead to better parameterisations in urban air pollution models.
Specific scientific objectives of experimental work in the frame of SATURN include:
Knowledge and tools acquired in the frame of SATURN as a whole will be integrated in order to make it directly suitable for applications related to environmental policy ("Framework Project", see section 4.5d). Moreover, specific deliverables will be developed which could be directly used in support of urban air quality management.
4.5 Work programme
For a better overall management of the subproject, work in SATURN is organised into four Main Groups of activities (MGs). In order to meet the above presented scientific aims of SATURN, several tasks will be addressed within each MG.
(a) Model development (SATURN-MOD)
Local scale model development (task MOD1)
The following activities are planned:
Urban scale model development (task MOD2)
The work plan for this task includes:
Scale interactions in models (task MOD3)
Contributions related to this task deal with one or several aspects of two strongly inter-related topics:
Chemical modules with emphasis on heterogeneous chemistry (task MOD4)
The work plan for this task includes:
(b) Model evaluation (SATURN-VAL)
The objective of SATURN-VAL is to provide the framework for validating urban scale models. This will be accomplished
Moreover, SATURN-VAL will host model validation activities.
Evaluation procedures (task VAL1)
This significant task will include the following activities:
Specifications for data relevant to model evaluation (task VAL2)
This task will consist of contributions devoted to various quantities relevant to model evaluation. It is anticipated that each contribution will be structured as follows:
Apparently, this task will be closely related to VAL1, as the data needed for model evaluation strongly depend on the concept of the evaluation procedure, whereas the availability of individual data limits the applicability of specific evaluation procedures.
Emission inventories for model validation activities (task VAL3)
This task will be performed in close co-operation with the EUROTRAC-2 subproject GENEMIS-2. Activities include
The concepts for the first three will be developed on the basis of existing international guidelines and databases. Specifically, CORINAIR recommendations and results of ongoing research projects like MEET (Methodology for Estimating Emissions of Traffic) will be taken into account. A link will also be established to the Topic Centre on Air Emissions of the EEA. Special emphasis will be put on the specific demands of urban inventories, above all a high temporal and spatial resolution.
One of the most important tasks of the planned collaboration with GENEMIS-2 will be to define a harmonised method for setting up high resolution urban emission inventories at the minimum input requirements. Moreover, special care will be taken to properly define the emission factors used, as this is an important issue for any intercomparison of emission inventories. Reliable sources of emission data will be listed and the impact of the emission factor accuracy will be investigated. In this context, different methodological approaches will be used for certain source categories (bottom-up or top-down).
Assessment of model validity in the frame of model intercomparisons (task VAL4)
The work plan for this task includes
In principle, any research group will have the possibility to participate at the model intercomparison activities. Groups outside of SATURN will, however, be requested to provide specified model documentation needed for the quality assurance measures pursued in SATURN (see section 4.6).
(c) Experiments (SATURN-EXP)
Local scale field experiments (task EXP1)
This task will include the following activities:
Urban scale field experiments (task EXP2)
Contributions related to this task are expected to lead to a better understanding of transport and chemical transformations at the urban scale. Moreover, reliable datasets will be generated for testing elements of models applicable for European urban case studies. Specifically, the following activities are planned:
Large urban scale field campaigns (task EXP3)
Comprehensive model validation datasets are expected to result from field campaigns which are planned in urban areas representative for conditions prevailing in different parts of Europe. Each of these campaigns satisfies the following criteria:
Particulate matter field experiments (task EXP4)
The work plan for this task includes:
(d) Integration (SATURN-INT)
Contributions to this Main Group of activities are hard to classify into strict categories. Even if they have a very particular aim, these contributions typically address many elements, though with varying emphasis. Of the proposed contributions, some are at the same time related to tasks in other MGs (thus dealing for instance with process oriented studies, measuring campaigns and model development) and include the air quality management purpose as one of the major goals or as the anticipated application of the results, while other contributions have "integration" (i.e., the development of an integrated model system) as their primary objective, and will develop elements only as far as need
Among the four tasks addressed in this MG, INT1 has a special role (see below). Contributions related to tasks INT2-4 are expected to lead to deliverables which could be directly used for urban air quality management. In spite of the strong preference for contributions representing new developments, in exceptional cases also the demonstration of capabilities of existing tools might be acceptable (e.g., comparative application of an existing tool to several urban areas).
Framework Project (task INT1)
In principle, all contributions to SATURN are associated to this task, even contributions having stronger links with one of the other MGs. INT1 represents a common framework for all contributions to SATURN providing results that are potentially useful for air quality management systems and integrated assessment methods. Because of the large group of contributions addressed, the structure of INT1 differs from that of other tasks from the organisation standpoint. Given the importance and complexity of INT1 - the development of an integration structure is one of the most important reasons for the existence of SATURN - it is intended to structure this task as a project, called the Framework Project (see section 4.10).
Integrated monitoring/modelling systems (task INT2)
Contributions related to this task include both experimental studies and modelling work with the aim to achieve a synergetic effect from this combination. Examples are
Comprehensive urban air quality management systems (task INT3)
This task aims at the improvement of existing and the development of new urban air quality management systems (AQMS), i.e., systems integrating all extisting information provided by measurements, models and scenario generators. Specifically, the following is expected to be achieved:
Exposure assessment (task INT4)
Contributions related to this task aim to assess population exposure taking into account model results and data on population density in urban areas. Currently, it is not anticipated that exposure assessment methods will include the assessment of indoor air quality or the behaviour of the population.
4.6 Quality assurance
The main aim of SATURN is to improve the procedure for evaluating air pollution models, i.e., for checking their validity for practical applications. Thus, quality assurance and control (QA/QC) are inherent ingredients of this subproject. In fact, all potential PIs declared explicitly their willingness to comply with the agreed QA/QC requirements.
Already the organisation of SATURN guarantees QA/QC: The subproject is subdivided into sixteen manageable tasks, the leader of which are also responsible that QA/QC procedures are followed. Moreover, four Steering Group members are in charge of supervising QA in the subproject as a whole (see section 5.3). Finally, the aim of the Framework Project is to ensure that quality assured deliverables from the scientific work in SATURN are extracted to support environmental management at the urban scale.
For assessing the quality of data to be used for model evaluation, it is essential that detailed documentation exists, including the description of the measurements (methods, measurement periods, averaging times, sampling frequency, interferences from other parameters etc.), QA/QC documentation and data format documentation. All PIs planning to supply such data will be requested to provide this documentation.
In the case of field experiments information will be required on the site (area type and size, distance from major sources, estimate of site representativeness etc.) and on the micro-scale environment (e.g., distance from obstacles, sources, height above ground and sea level, air intake). Documentation of laboratory experiments will have to contain detailed descriptions of the experimental set up and the processes the experiments have been designed for, including an evaluation of the limitations. Finally, in the case of wind tunnel experiments specific criteria will have to be followed in order to assure the quality and usefulness of the generated data (among other, thorough dimensional analysis and comparisons of velocity profiles and turbulence spectra with atmospheric measurements).
An obvious prerequisite for meeting the objectives of SATURN is the generation of high quality validation datasets which will mainly consist of data from field studies and laboratory experiments. The former typically include emission data, air quality data, meteorological data and traffic data, whereas the latter are usually derived from chemical process studies, wind tunnel studies, aerosol studies etc.. In some cases, validation datasets may also contain data from numerical experiments.
With the aim to arrive at high quality validation datasets, but also to ensure in general an efficient co-operation within SATURN, data resulting from the scientific work will be processed for fast and secure transfer as well as for proper archivation. Where appropriate, data will be organised following the pattern of widely accepted database systems.
Like all other SATURN deliverables, generated databases will be submitted via the respective task leader to the Steering Group of the subproject. Four Steering Group members will be responsible for the dissemination of the data obtained (see section 5.3). In the case of data from experimental activities a review procedure is foreseen with emphasis on the data quality documentation (see section 4.6). If approved by the Steering Group, such data will be made accessible through the World Wide Web. As far as model results are concerned, the Steering Group will support archiving the corresponding data only in case that full documentation of the models involved is available.
4.8 Operational plan
The scientific work envisaged within SATURN will be subdivided into three phases (A, B and C) which are expected to last two years each. A kick-off workshop is planned at the beginning of phase A for concerting as much as possible the actions in the subproject. Towards the end of both phases A and B, a review process will be initiated for evaluating the scientific progress in the subproject. Although most of this review will be organised within SATURN, external opinions will be sought for as well. Depending on the outcome of the review process, it is in principle possible to reconcile the objectives of the subproject with its general proceedings.
The expected achievements in the three phases of SATURN are as follows:
More details on the time schedule envisaged are given in tabular form in section 5.5. Both operational plan and overall time schedule reflect the general lay-out of SATURN which would ensure achieving the scientific goals of the subproject. Given the bottom-up nature of EUROTRAC-2, this does not necessarily imply that all individual contributions will fully conform to this lay-out (see also the time schedules of individual contributions as contrasted to the overall time schedule). As one of its major tasks, the Steering Group of SATURN will, therefore, endeavour that each Principal Investigator adapts as much as possible to the operational plan, as otherwise the overall subproject would not necessarily benefit from the success of the individual contributions.
4.9 Collaboration with other subprojects of EUROTRAC-2
Several activities planned in SATURN are relevant to the aims of other more thematical subprojects of EUROTRAC-2. In this sense, interfaces between SATURN and other subprojects will be carefully defined from the beginning of the project and, where appropriate, an intense co-operation will be maintained over the whole duration of the project.
Along these lines, a collaboration framework has been already agreed with GENEMIS-2: VAL3 will be linked to a GENEMIS-2 subgroup consisting of PIs who want to either develop methods for generating urban emission inventories or to set up urban emission inventories. It is agreed that this GENEMIS-2 subgroup and VAL3 will have the same leader, who will also be member of the GENEMIS-2 Steering Group. Contributors to VAL3 will have a double allocation - to SATURN and to GENEMIS-2, i.e., they will have to send identical annual reports to both subprojects.
Similar arrangements are aimed at in the case of GLOREAM and LOOP. Specifically, contributors to MOD2 (Urban scale model development) could participate at activities of the GLOREAM subgroup dealing with mesoscale modelling. Such a subgroup could represent a forum for mesoscale modelling activities in EUROTRAC-2, i.e., also in subprojects other than SATURN and GLOREAM (e.g., LOOP). Members of MOD2 would have a double allocation - to both SATURN and GLOREAM.
Finally, a dense collaboration will most probably emerge between contributors to task MOD4 and the Multi-Phase Modelling Group (MPM) of subproject CMD. The specifications of this collaboration will be agreed upon in the first year of the project.
4.10 Structure to integrate scientific elements for urban air quality management
The Steering Group of SATURN will have as its responsibility to bring the contributions together, to facilitate the exchange of results between the contributors and to stimulate the development of a common view on the scientific problems and solutions regarding the urban environment. The diversity of the aims of the various contributions to SATURN makes it difficult to bring the results into a common framework and to promote that the results will be optimal from the viewpoint of air quality management. For example, the form in which new data are provided should not only be optimal for exchange in the scientific field, but it should - as far as relevant - also be useful for regulatory purposes. Also, SATURN should stimulate research on fields where current knowledge is insufficient or not operational for regulatory purposes.
Structuring SATURN, which combines individual contributions, each with its individual sponsor and individual goals, as a large scientific effort to take further steps towards practical application of the acquired knowledge and tools, will require a considerable effort. For information exchange at the scientific level the scientific infrastructure will develop along the lines set out already in the first phase of EUROTRAC, but the infrastructure for optimizing the results towards practical application in air quality management will need additional efforts which go beyond those that are available to the members of the Steering Group.
For this reason, a Framework Project will evolve during the execution of SATURN with the main aim to develop a common structure for the results (data, models, methods) of the contributions. It will provide an application oriented framework to be used in the reports of the contributions. It will monitor the performance of the contributions taken together, analyse the results in terms of applicability, stimulate the new contributions on fields that are insufficiently covered and annually report the results and developments to the urban and other environmental managers. In meetings with municipal authorities the results will be discussed in terms of the usefulness at the air quality management level, and the results of the meeting will be communicated to the scientific community.
From the above it is clear that the Framework Project has similar aims to the "Application Project" in the first phase of EUROTRAC. In contrast to the latter project, however, the contributions of individual PIs will be evaluated during the execution of SATURN and not short before its completion.
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Kretzschmar, J.G. and Cosemans, G. (eds), Proceedings of the 4th Workshop on Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes, Oostend, Belgium, 1996.
Schatzmann, M., and Arend, M. (eds), COST Action 615, Database, monitoring and modelling of urban air pollution, Report publ. By the European Commission, DG XII, 1995.
Stanners, D. and Bourdeau, Ph. (eds), Europe's Environment - The Dobrs Assessment, European Environment Agency, Copenhagen, 1995.
Sini, J.-F., Anquetin, S. and Mestayer, P.G., Pollutant dispersion and thermal effects in urban street canyons, Atmos. Environ. 30, 2659-2677, 1996.
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5 Organisation of the subproject
5.1 Subproject Coordinator
Nicolas Moussiopoulos, Thessaloniki, Greece
Born 1956 in Athens, Dr. Nicolas Moussiopoulos studied Mechanical Engineering in Karlsruhe, Germany, where he also received his PhD in Thermodynamics in 1982. In the period 1982-1989 he was leading the Research Group on Atmospheric Transport Phenomena at the University of Karlsruhe. After his 'habilitation' in February 1989, he was appointed Professor and Director of the Laboratory of Heat Transfer and Environmental Engineering at the Aristotle University Thessaloniki, Greece, which is also his current affiliation. Since 1996, he is also a Honorary Professor at the Department of Mechanical Engineering of the University of Karlsruhe. In the first phase of EUROTRAC he was Deputy Coordinator of EUMAC, member of the Application Project and the representative of Greece to the IEC. In June 1996 he was appointed to the Scientific Steering Committee of EUROTRAC-2. His research work deals primarily with the development of atmospheric wind and dispersion models and their application at the local-to-regional scale. He has more than 150 scientific publications, including 8 books and about 30 papers in peer-reviewed journals. 1990 he received the Heinrich Hertz Award.
5.2 Deputy Coordinators
K. Dick van den Hout Apeldoorn, The Netherlands
Patrice Mestayer Nantes, France
Finn Palmgren Roskilde, Denmark
Michael Schatzmann Hamburg, Germany
5.3 Steering Group with agreed division of responsibilities
|Annual Reports||Mestayer||Schatzmann||Palmgren||van den Hout|
|Ex officio||van Aalst|
5.4 Interactions in SATURN
The pursued structure of SATURN is expected to favour the subproject's feasibility and operationality: Activities are subdivided into four Main Groups (MG) and sixteen tasks, all of which have a manageable size. Close co-operation within each task team will ensure a steady progress of the scientific research envisaged. At the same time, sufficient precautions are taken to avoid an independent evolution of work in individual task teams: Firstly, most PIs are involved in more than one tasks, thus providing clear links between the tasks. Secondly, regular concertation contacts (normally via e-mail) will take place. Finally, the "Framework Project", which corresponds to task INT1, will represent an additional guarantee for coordinated work in the subproject.
5.6 Total personnel requirements and expenditure
|Personnel / man-years||90.7||103.7||90.9||73.4||58.1||29.0||445.8|
|Yearly cost / MECU||4.415||5.535||4.747||3.076||2.035||0.915||20.733|
Contributions of individual principal investigators
Update: 24. July 1997