Introduction About EUROTRAC-2 The goal of EUROTRAC-2 EUROTRAC-2 was the second phase of the project on the Transport and Chemical Transformation of Environmentally Relevant Trace Constituents in the Troposphere over Europe. It was accepted as a project within the EUREKA initiative (No. 1489) in February 1996 to run until the end of December 2002. The project followed on from the first phase of EUROTRAC (EUREKA project No. 7) which was carried out from 1988 - 1995. The goal of EUROTRAC-2 has been to improve the quantitative understanding of the factors determining the formation, transport, chemical transformation, deposition and impact of photo- oxidants, aerosols, acidifying substances, mercury and persistent organic pollutants (POPs) in the troposphere, and in this way to contribute directly to the further development of strategies for reducing the ambient concentrations and deposition fluxes of these species. EUROTRAC-2 has assisted in alleviating the growing environmental problems which stem from these species by integrating scientific results with policy needs. Although EUROTRAC has not funded research directly, it has been a platform for the exchange of information, knowledge and experience and co-operation in joint projects. The results obtained have provided a common scientific understanding upon which effective environmental abatement and control strategies throughout Europe have been and will be based. A European network of scientists has been formed, qualified to advise their own governments and the international bodies on environmental issues connected with the atmosphere. In both phases of EUROTRAC, the research resources of the participating countries and the European Union have been brought together to create viable active research groups to address interdisciplinary and international, transboundary problems. EUROTRAC has contributed strongly to building European capacity for scientific research in air pollution. As well as being a platform covering all Europe, EUROTRAC has also facilitated the training of young scientists. The active involvement in EUROTRAC of many groups in Central and Eastern Europe has also been of great importance. This has helped to transfer knowledge to countries with lower economic activity, less scientific facilities, and often more severe environmental problems. The reasons for EUROTRAC-2 to exist The air quality in large areas of Europe at the beginning of EUROTRAC-2, and also today, is still far from acceptable and often above limit values, despite international agreements and the efforts made in various countries to reduce the emissions of major pollutants. The atmospheric changes being brought about by human activities can have serious effects on air quality, human health, the ecosystem, materials, acidification and eutrophication, and on climate change. 2 Introduction There was, and still is, much public concern over the high concentrations of fine particles and ozone over large parts of Europe. To meet the obvious challenges in abating these environmental problems, also in a cost-effective way, requires an in-depth understanding of atmospheric chemistry and its interaction with the biosphere. EUROTRAC was set up to create this understanding and to provide a scientific basis for abatement strategies. EUROTRAC-2 has built on the success of the first phase to intensify and extend this work. An essential feature of the problems mentioned is the complexity and intertwining of processes contributing to the cycle of pollutants between their emission and deposition. This includes the physical and chemical transformation of primary pollutants into secondary products, the interrelation between primary and secondary pollutants, transport and deposition, and the impact on the biosphere. Some compounds contribute to a number of environmental problems; for example, the nitrogen oxides emitted by traffic and industry affect the formation of photo-oxidants and aerosols and also the deposition of nutrients. The investigation, interpretation and understanding of such a complex field are beyond the capacity of single groups, institutes or disciplines; these problems require a thorough, interdisciplinary approach on a European scale. They are also facilitated by coordinated planning and pooling of resources. Furthermore, the atmospheric transport of pollutants does not recognise international boundaries. With the small geographical size of Europe, pollutants produced in one country are frequently exported to neighbouring countries where environmental damage is produced by the primary and secondary pollutants. Thus the environmental problems in Europe are literally transboundary and require effective, internationally coordinated action in research as well as in abatement and reduction measures. These elements together were the reasons for the creation of EUROTRAC and, subsequently, EUROTRAC-2. The objectives of EUROTRAC-2 were specified as: · Quantification of atmospheric interactions To quantify the anthropogenic and natural contributions of relevant emissions and atmospheric processes to the abundance and the long term changes of photo-oxidants, aerosols, acidifying substances, mercury and POPs in the troposphere. · Evaluation of feedback mechanisms To evaluate the consequences of feedback mechanisms, for example, the feedback between the concentrations of tropospheric photo-oxidants and biogenic emissions, the feedback between the concentrations of photo- oxidants and those of climatically relevant atmospheric constituents, and the feedback between the changing intensity of ultraviolet radiation and photo- oxidant production. · Contribution to the formulation of abatement strategies and prediction of future air quality To contribute to the formulation and improvement of strategies for reducing the anthropogenic contribution to the abundance of photo-oxidants, aerosols, Introduction 3 acidifying substances, mercury and POPs and to the prediction of future air quality on shorter and longer time scales. For a more detailed description, see the EUROTRAC-2 Project Description and Handbook (1998). A number of scientific tasks were defined to achieve these objectives. In broad terms these aimed to improve the scientific understanding of the emission rates, to improve the monitoring capacity and strategy, to improve the chemistry transport models currently used in the policy work on abatement, to improve the understanding of how air pollutants affect the air quality in cities and, finally, to improve the understanding of the deposition mechanisms and their rates. The formulation of these tasks was based on the current understanding of what was required in order to support policy development in these fields at the initiation of the project. Obviously, modifications and changes have been made in the focus of the research in the six years of EUROTRAC-2, to reflect changing priorities. The principal policy drivers have been the Convention on Long-range Transboundary Air Pollution under the aegis of the United Nations Economic Commission for Europe (UNECE) and the air quality legislation of the European Union. The strategy of EUROTRAC-2 By its nature EUROTRAC-2 was to a large extent a scientific project and not, in the first place, a policy and assessment project. All research projects in EUROTRAC-2 were funded by national bodies, or by international organisations, such as the EC research directorate. The subproject coordinators and the members of the various committees were all active on a voluntary basis. Because the intention was to address environmentally relevant issues, the strategy of EUROTRAC-2 has been to integrate with environmental policy issues as far as possible, whilst keeping its scientific character. To intensify the support for policy making compared to the first phase, an Environmental Assessment Group (EAG) was established in EUROTRAC-2 including representatives from the technical centres of UNECE/EMEP, the EEA Topic Centre for Air and Climate Change and the EC Environment Directorate. The main task of the EAG was to ensure that the environmental issues of current concern to the participating countries were addressed in the scientific programme and to present the scientific findings to those responsible for policy management in Europe. The structure of EUROTRAC-2 EUROTRAC-2, as a follow-up of the first phase of EUROTRAC, was set up as a project lasting for a period of six years. The analysis made at the end of the first phase in the report Photo-oxidants, Acidification and Tools: Policy Applications of EUROTRAC Results (Borrell et al., 1997) defined the uncertainties still existing upon which EUROTRAC-2 was then focussed. EUROTRAC-2 was basically a “bottom-up” project, with only limited central funding for coordination activities including the maintenance of a small 4 Introduction secretariat. It was organised around a number of scientific subprojects and administered by three committees and the international scientific secretariat (see Figure 1). International Executive Committee (IEC) Scientific Steering Environmental Committee Assessment Group (SSC) (EAG) Internat. Scientific Secretariat (ISS) Subprojects AEROSOL BIATEX-2 CAPMAN CMD EXPORT-E2 GENEMIS GLOREAM LOOP MEPOP PROCLOUD SATURN TOR-2 TRAP45 TROPOSAT Figure 1. Organisation scheme of EUROTRAC-2. · Organisation of scientific work The research within EUROTRAC-2 was organised among 14 subprojects, each with clearly formulated goals. The scientific programme of each subproject was suggested by the subproject group itself and was finally agreed after consultation with the SSC, EAG and IEC. The work of the subprojects was fostered through joint workshops, meetings and, where appropriate, field campaigns. · Project management The International Executive Committee (IEC) held the overall responsibility for the project. Members were appointed by the funding or environmental agencies of the participating countries together with a representative from the European Commission (EC). · Scientific steering The Scientific Steering Committee (SSC) was responsible for the scientific programme, setting the scientific direction and focus, approving proposals for subprojects and conducting reviews of scientific progress. It consisted of 15 leading scientists. · Environmental assessment The Environmental Assessment Group (EAG) ensured that relevant environmental issues were addressed within the scientific programme. It was Introduction 5 also responsible for the exchange of scientific information between EUROTRAC-2 and the agencies responsible for environmental policy development. The members belonged to environmental agencies and programmes, or were experts in the application of environmental policy. · Administrative coordination The International Scientific Secretariat (ISS) was responsible for the administrative coordination of EUROTRAC-2. It maintained contacts with the committees, subproject coordinators and principal investigators. The strengths of EUROTRAC-2 EUROTRAC-2 has achieved the harnessing of a variety of resources in over 30 participating countries to support European projects with pan-European goals. The number of groups active in EUROTRAC-2 over the course of the project has been more than 300. This has enabled active, interdisciplinary research groups to be created of a viable size in areas of importance and the close coordination at each level has ensured that most goals specifically set by the different subprojects within EUROTRAC-2 have been achieved. Its strength has also been the bottom-up structure and the scientific network established which was essential in generating and promoting new ideas. Networking has been facilitated by annual subproject workshops and a biennial Symposium which has regularly attracted 400 or more participants. Many young scientists have given their first talk at a EUROTRAC workshop and have made many contacts and friends at the EUROTRAC Symposia. The outcome of EUROTRAC-2 has included almost 900 scientific papers published in the peer- reviewed literature to date as well as more than 100 PhD theses. In addition, EUROTRAC-2 has produced a wealth of other activity such as contributions to scientific assessments and conferences, book chapters and review articles. EUROTRAC-2 has shown a successful collaboration between basic and more applied research. The continuous dialogue between basic and applied science is a long-term, powerful tool to promote new scientific findings into application and policy development. EUROTRAC-2 also provided a trans-national platform that helped coordinate national research programmes within Europe in close cooperation with the European Commission, contributing to a European consensus on environmental strategies (see also EUROTRAC-2 Mid-term Review, 2001). The successes of EUROTRAC-2 First, an overwhelming amount of top-quality science has been created better to quantify the anthropogenic and natural contributions of relevant emissions and atmospheric processes to the abundance and the long term changes of photo- oxidants, aerosols, acidifying substances, mercury and POPs in the troposphere. Special attention has been given to the development of instruments and chemical transport models for aerosols. Furthermore, research has started into the use and usability of satellite data for tropospheric research and into the quantification of 6 Introduction the global impact on the concentration levels in the European troposphere as well as the export of pollutants from European regions. EUROTRAC-2 has stimulated a wealth of scientific activities, bringing together funding from national and international programmes. Its approach, combining a basically bottom-up structure with oversight by the respective committees, served to create a new European dimension in atmospheric research. In its second phase, the work of EUROTRAC has been extended and deepened to become a very successful platform in Europe for the study of the troposphere in all its environmental aspects. It has helped to forge the scientific consensus which is essential to underpin environmental policy development in Europe. EUROTRAC-2 has also served as an environment in which young scientists can become familiar with the current state of knowledge and with colleagues from other countries. Its outreach to involve research groups within Central Europe and in Eastern Europe formerly not active in European research programmes has been especially valuable. About the Synthesis and Integration Project To assess the success of EUROTRAC-2 in supporting policy development, a Synthesis and Integration Project was set up. The aim was to address specific cross-cutting themes, covering results from the different subprojects. Viewing the final reports of the subprojects as “horizontal” reporting, the themes addressed in synthesis and integration were vertical cross-sections. Five themes were selected: · Emissions of gases and particles · Deposition fluxes of air pollutants · Tropospheric ozone and its control · Urban and local scale air pollution · Tropospheric aerosols and clouds These themes were not intended to cover all the results of EUROTRAC-2, but to give specific examples, to tell specific stories, and to answer specific, policy- relevant questions. The full scientific results of EUROTRAC-2 are presented in detail in the final reports of the subprojects which are published separately. Thus, in this Synthesis and Integration report, ample attention is given to certain topics, ozone and aerosols for example, while other topics such as wet deposition and POPs receive less attention. This does not reflect any strict priority with respect to environmental issues, but rather illustrates for some selected topics how scientific results can be integrated to support policy development. Results on these aspects for the remaining topics can be found in the subproject final reports. There is also an overview of the work of each of the 14 subprojects in the companion volume to this book: Towards Cleaner Air for Europe - Science, Tools and Applications Part 2 (Midgley and Reuther, eds., 2003). Introduction 7 Ideally, the process of developing sound environmental policy should be a serial one. The first step is to develop an understanding - ideally as complete as possible - of the scientific nature of the system in question. Once this understanding has been achieved, tools such as mathematical models of the system can be developed. These tools can be used iteratively to increase our understanding of the system and for the purposes of assessment and policy development. In EUROTRAC-2, much effort has been devoted to following this path from science via tools to policy. However, it should be made clear that the progress from science to policy is, in reality, not that straightforward. Policies have to be developed based necessarily upon an incomplete knowledge of the system in question. The precautionary principle is often invoked, i.e., that if the consequences of a potential environmental problem are sufficiently grave, then regulations should be put into effect even though the scientific basis is not yet complete. While this approach may be entirely justified, or even necessary in some cases, it should be noted that truly sound policy cannot be developed if the science aspect is ignored. Policy should be refined and re-evaluated as new information becomes available and investigations into specific environmental issues need not necessarily stop because a first strategy for policy has been developed. For each theme chapter in this book, an attempt has been made to follow the path described above, which means addressing science, tools, and policy (Figure 2). Tools Assessment of Scientific Usefulness for Uncertainties Understanding Policy-making Quality Assessment Figure 2. Schematic diagram of the S&I chapter structure. It will be clear to the reader that the style of each chapter reflects the approach of the individual authors who were given overall guidelines but were not constrained into a meaningless consistency in presentation of the five themes. The general outline of each chapter (explicitly or implicitly) is an overview of the current policy-related questions and issues, followed by: · What have we learned about...? · What new tools do we have? · What can we contribute to policy development? (in which the policy-related questions are answered as far as possible), and · What are the most pressing needs? The first chapter Emissions of Gases and Particles to the Atmosphere in Europe addresses the progress made with respect to the emissions of anthropogenic and biogenic volatile organic compounds (VOC), the biogenic emissions of nitrogen oxides, and, as a relatively new subject, the emissions of particles: anthropogenic, biogenic and natural. Also current knowledge 8 Introduction concerning the emissions of POPs and mercury is presented. Special attention is given to the assessment of the accuracy of the emission data.. The following chapter considers Deposition Fluxes of Air Pollutants to Terrestrial Surfaces in Europe. Both emissions and deposition of ammonia are treated here because of the close and complicated emission/deposition/re- emission cycle of ammonia. New findings concerning the fluxes of sulphur dioxide and its interaction with ammonia are presented. Deposition of nitrogen oxides, ozone and particles are also discussed. Tropospheric Ozone and its Control is discussed in the third chapter. The key question addressed here is: which scientific findings are available to determine the impact of the global and hemispheric background to the concentrations in the troposphere over Europe. The chapter describes that, notwithstanding the clear impact that the hemispherical background has on ozone over Europe, the amount of controllable European ozone is large enough to require specific European abatement strategies. The impact on episodic peak ozone concentrations across Europe of the VOC Protocol to the UNECE Convention on Long-range Transboundary Air Pollution is also analysed. Urban and Local Scale Air Pollution is the subject of the next chapter. Various aspects are addressed associated with urban and local scale air quality assessments and their uncertainty. The chapter discusses in detail scientific improvements in estimating urban emissions and describing urban aerosols. Improvements of air pollution models, new approaches towards their validation and methods for multi-scale analyses are also presented. Better scientific insight and the availability of refined practical tools resulted in the formulation of improved urban air quality management systems. Such systems are very useful for addressing various important policy issues related to urban air quality. The last thematic chapter discusses the subject of Tropospheric Aerosols and Clouds, showing the progress made in this rapidly developing new area and the first steps made towards the development of tools/models which enable the analysis of abatement strategies. These thematic chapters are followed by a Summary and Conclusions chapter in which selected, significant scientific results from the work within the EUROTRAC-2 project are linked to their relevance to policy application and future needs. Finally some reflections on EUROTRAC-2 and the future are presented.