1. EIONET 2008, Bruge Guidance on the use of models for the European air quality directive: an activity of FAIRMODE Bruce Denby 1, Steinar Larssen 1, Cristina Guerreiro 1, John Douros 2, Nicolas Moussiopoulos 2, Lia Fragkou 2, Michael Gauss 3, Helge Olesen 4, Ana Magarida Costa 5 1 Norwegian Institute for Air Research (NILU), Norway 2 Laboratory of Heat Transfer and Environmental Engineering, Aristotle University, Thessaloniki, Greece 3 Norwegian Meteorological Institute, Norway 4 NERI, Denmark 5 University of Aveiro, Portugal EIONET, September 2008, Bruge

2. EIONET 2008, Bruge Overview Aim of the guidance document Audience and structure Why use models? Contents of the guidance document Chapter 3: Interpretation of the directive 3.2 When can models be used for assessment? 3.6 Model quality objectives as described in the directive Chapter 7: Air quality planning Planning, Danish example Transboundary air pollution, EMEP example Chapter 8: Special topics Status and future

3. EIONET 2008, Bruge Activities of FAIRMODE working group 1 Major activity this year is the initiation and writing of a guidance document for the use of models in regard to the new air quality directive Aim of the guidance document to provide guidance for the use of air quality modelling in regard to the new air quality directive (and the directive on heavy metals in ambient air) to promote best practices in air quality modelling and assessment to provide a centralised forum and reference point for the application of models in regard to the air quality directive

4. EIONET 2008, Bruge Intended audience For use by authorities, consultancies and research bodies involved in air quality modelling for assessment and mitigation planning that address the European air quality directives. Overall structure of the document The major text of the document and targeted examples should provide the basic information for authorities to make decisions on whether or not to employ modelling in their assessment. The supporting appendices and references should provide broad overviews as well as specific examples to help guide modellers in the application of their methodologies.

5. EIONET 2008, Bruge Why use models? The spatial coverage of monitoring is extremely limited. Modelling can provide complete spatial coverage of air quality. Modelling can be applied prognostically. It can be used to predict the air quality as a result of changes in emissions or meteorology. Modelling provides an improved understanding of the causes and links that determine air quality. Why use models in regard to the directive? Models can provide assessment within zones in areas where monitoring is not carried out. The number of monitoring sites can be reduced significantly. Models can be used to develop and detail measures taken to reduce poor air quality. Models can be used for the evaluation of source contributions.

6. EIONET 2008, Bruge Why not to use models? Models require extensive input data, particularly emissions and meteorology, which are not always reliable or easily acquired. Models remain uncertain in their predictions and extensive validation is required before models can be applied and believed. The ability of models to represent the real world is very limited, e.g. spatial resolution and process descriptions. Models remain a representation of reality. Effective and quality controlled modelling requires expert users under most situations.

7. EIONET 2008, Bruge Contents of the guidance document by chapter 1.Introduction 2.Summary of the 2008 air quality directive 3.Interpretation of the directive in regard to modelling 4.Reporting when using models 5.Model validation, quality assurance and control 6.Application of models for assessment 7.Application of models for air quality planning 8.Special topics 9.References 10.Annexes

8. EIONET 2008, Bruge Chapter 3: Interpretation of the directive in regard to modelling 3.1 Model applications in the air quality directives 3.2 When can models be used for assessment? 3.3 Combined use of measurements and models for assessment 3.4 What types of models can be used? 3.5 The spatial and temporal resolution of the models 3.6 Model quality objectives as described in the directives 3.6.1 Mathematical formulation of the directive quality objectives 3.6.2 Example of an uncertainty estimate 3.6.3 Interpretation of the ‘90% of stations’ requirement 3.6.4 Representative scale of models and observations

9. EIONET 2008, Bruge 3.2 When can models be used for assessment? The directive defines a range of situations where models may be applied for assessment instead of, or in combination with, fixed measurements 1. Models can always be used to supplement fixed measurement data no matter the pollutant levels. The advantage of this is that the number of monitoring stations may be reduced ( Articles 7.3, 10.3 and 14.2). 2. Article 6 of the directive stipulates when, and in what way, modelling may be used for air quality assessment, not including ozone, based on the level of pollutants. These are: - Modelling can be used to supplement monitoring when a zone is in exceedance of the upper assessment threshold - Modelling can be used in combination with monitoring when a zone is in exceedance of the lower assessment threshold - Modelling can be used to replace monitoring when a zone is below the lower assessment threshold 3. Article 9.2 and Annex II.B goes on to state that, when monitoring data is not available for 5 years, the period for which the threshold levels are to be assessed, then short term measurement campaigns combined with modelling may be used to determine both upper and lower exceedance thresholds.

10. EIONET 2008, Bruge 3.6 Model quality objectives as described in the directive 3.6.1 Mathematical formulation of the directive quality objectives As in the previous directives the wording of this text remains ambiguous. Since values are to be calculated, a mathematical formulae would have made the meaning much clearer. As such the term ‘model uncertainty’ remains open to interpretation. Despite this we suggest the following interpretation that we call, for want of another name, the Relative Directive Error (RDE) and define it mathematically at a single station as follows: where O LV is the closest observed concentration to the limit value concentration ( LV ) and M LV is the correspondingly ranked modelled concentration. The maximum of this value found at 90% of the available stations is then the Maximum Relative Directive Error (MRDE).

11. EIONET 2008, Bruge 7.1 Air quality plans Example: Integrated Monitoring and Assessment in Urban Air Quality Management in Copenhagen, Denmark Integrated Monitoring and Assessment (IMA) is defined as the combined use of measurements and model calculations. The use of IMA has been the guiding principle for assessment of air quality and deposition in Denmark within different areas. A comprehensive overview of the Danish approach to IMA is provided by Hertel et al. (2007). This example focuses on how IMA is applied in urban air quality assessment and management in Copenhagen, Denmark. The city of Copenhagen has about 600,000 inhabitants and the Greater Copenhagen Area has about 1.8 million inhabitants. The National Environmental Research Institute (NERI) operates the Danish Urban Air Quality Monitoring Programme …

12. EIONET 2008, Bruge 7.3 Transboundary air pollution Example: Application of the EMEP model for determining transboundary contributions to air quality The mandate of EMEP (European Monitoring and Evaluation Programme, http://www.emep.int ) is to provide sound scientific support for the Convention on Long-range Transboundary Air Pollution (LRTAP), in particular in the areas of atmospheric monitoring, modelling, emission inventories/projections, and integrated assessments. Each year EMEP provides information on transboundary pollution fluxes inside the EMEP area (including all countries that have signed the Convention, and their surroundings), relying on information on emission sources and monitoring data provided by the Parties to the Convention. In 2008 the EMEP area has been extended to include the EECCA countries (Eastern Europe, Caucasus, and Central Asia). An integral part of the annual EMEP reports are the Source- Receptor matrices, which …

13. EIONET 2008, Bruge Chapter 8: Special topics 8.1 Assessing the non-anthropogenic (natural source) contribution to exceedances 8.1.1 Assessing the contribution of winter sanding or salting of roads to PM exceedances 8.1.2 Assessing the contribution of wind blown and Saharan dust events to PM exceedances 8.1.3 Assessing the contribution of sea salt to PM exceedances 8.1.4 Assessing the contribution of wild-land fires to PM exceedances 8.2 Source apportionment using models 8.3 Air quality forecasting for information and alert thresholds

14. EIONET 2008, Bruge Status of the document The document will be continuously updated Approximately 60 % of the document has been completed (first draft) The current version will be available on the FAIRMODE web site before the FAIRMODE kick-off meeting in Cavtat A range of relevant and concise examples are still required on the topics of: -Reporting assessment to the Commission when using models -Reporting plans to the Commission when using models -Short term action plans -Etc… Contributors and reviewers are sort for the document

15. EIONET 2008, Bruge Future of the document After the EIONET and Cavtat meetings an assessment of comments and ideas will be made A work plan for the completion of the first phase of the document will be made Internal review to be carried out (steering committee) First phase of the document to be completed by the end of 2008 The document will be available on the FAIRMODE website The document, as well as other FAIRMODE activities, will be actively promoted at conferences, workshops and meetings The document will be regularly updated, e.g. results of WG2 will be included

16. EIONET 2008, Bruge For information and contributions contact Bruce Denby bde@nilu.no FAIRMODE website currently hosted by AUTH http://pandora.meng.auth.gr/modnet Thank you