joint TFEIP/TFMM workshop October 22, Dublin Understanding discrepancies between atmospheric model results and measurements given uncertainties in emission inventories, models and measurements Increase the interaction between inventory, modeling and observation community to understand the uncertainties in the different tools for studies on air pollution in the EMEP domain.

Objective: - interaction between communities (inventory, modeling, observation) - understand uncertainties in the different tools (for studies on air pollution in the EMEP domain. - understand where uncertainties need/could be decreased (to better understand the air pollution system source-effect) Introduction: our toolbox 3 Sessions:ozone, particulate matter and heavy metals

Questions we would like to address today: - To what extend do you think the uncertainty in the case presented should be attributed to model, inventory or observation uncertainty - Can we arrive at a consensus to quantified uncertainty estimates - What part of uncertainty can be attributed to lack of scientific understanding and what is due to poor quality of inventory, simplification in the models and/or errors in observations? - Where are the key gaps in understanding between the inventory, modeling and observation communities? - Are there similarities between case 1, 2 and 3? - What steps are needed to reduce the uncertainties?

End of introduction

Session 1 Ozone Background levels of ozone have substantially increased over Europe during the recent decades, most probably due to hemispheric transport. This increase has counteracted the effects of the reductions of European precursor emissions. Question: are we able to identify the reduction of ozone procures in Europe from the increase in background ozone concentrations due to hemispheric transport given the uncertainties in emission inventories, modeling and observations?

Session 2 Particulate matter According to the draft PM assessment report of the Task Force on Measurement and Modelling, the PM models currently used in policy development underestimate total PM10 and PM2.5 There are large uncertainties in the emissions inventories of the primary PM components especially with respect to the coarse PM fraction and of some PM precursors. Currently there are too few observations for satisfactory model verification. Question: may we conclude that the model underestimation of PM10 and PM2.5­­ are resulting from uncertainty in the emission inventories?

Session 3 Heavy metals In order to match modelling results to observed pollution levels of lead and cadmium in Europe, the analysis of EMEP/MSC-E suggest that the emission inventories are underestimating the emissions with a factor of 2-3. Question: May we trust the model finding that emission inventories might underestimate heavy metals by a factor of 2-3 and if so, what is causing the underestimation in the emission inventories?

Questions for session 1-3: - To what extend do you think that the uncertainty in the case presented in your session should be attributed to model, inventory or observation uncertainty - Can we arrive at a consensus to quantified uncertainty estimates - What part of uncertainty can be attributed to lack of scientific understanding and what part is due to poor quality of inventory, simplification in the models and/or errors in the observations? - Where are the key gaps in understanding between the inventory, modeling and observation communities - What steps are needed to reduce the uncertainties? - Do we see similarities between the 3 cases

Request from TFEIP chair: Conclusions and recommendations from the workshop Action plan to solve the HM discussion Request: small extra meeting on Monday evening to discuss on this: - Stegan Reis, Wilfried, Hugo, Joche Teloke, other?