1. National Environmental Research Institute, University of Aarhus, Denmark Impacts of climate change on air pollution levels in the Northern Hemisphere G. B. Hedegaard 1,2,3, J. Brandt 1, J. H. Christensen 1, L. Frohn 1, K. M. Hansen 1, C. Geels 1, M. Stendel 2. 1: National Environmental Research Institute, Department of atmospheric environment, University of Aarhus, Roskilde, Denmark 2: Danish Meteorological Institute, Copenhagen, Denmark 3: Niels Bohr Institute, Department of Geophysics, University of Copenhagen, Denmark CEEH External Workshop RISØ-DTU, Roskilde, Denmark February 6 th – 7 th 2008

2. National Environmental Research Institute, University of Aarhus, Denmark Background Air pollution MeteorologyEmissions NaturalAnthropogenic CONSTANT

3. National Environmental Research Institute, University of Aarhus, Denmark Aim: - To understand and quantify the impacts of - To understand and quantify the impacts of a changed climate on air pollution concentrations a changed climate on air pollution concentrations and depositions in the 21st century. Method: One-way coupling of a climate model to a chemical transport model, constant anthropogenic emissions.

4. National Environmental Research Institute, University of Aarhus, Denmark Experimental design ECHAM4 atmosphere OPYC3 ocean A2 emissions Emission data EMEP-GAIA-EDGAR Chemical Transport Model DEHM 3D dispersion 3D advection Chemistry Emissions Wet and dry deposition Sea ice surface/ mixed layer interior Climate Model

5. National Environmental Research Institute, University of Aarhus, Denmark Climate Model ECHAM4-OPYC3 Chemical Transport Model DEHM DEHM

6. National Environmental Research Institute, University of Aarhus, Denmark Emissions in the 4 simulations 1990s 2090s Constant 1990 Variable (MM5 and ECHAM4) Constant 1990 Simulations Validation Future projections - Time-sliced experiment in order to save computational time.

7. National Environmental Research Institute, University of Aarhus, Denmark Validation Validation period 1990-1999 Validation period 1990-1999 EMEP observations in Europe EMEP observations in Europe Comparison against MM5 simulation with known performance for many chemical species Comparison against MM5 simulation with known performance for many chemical species

8. National Environmental Research Institute, University of Aarhus, DenmarkTemperature Absolute difference [ºC]Significance Annual, averaged temp. 1990s [ºC] Annual, averaged temp. 2090s [ºC]

9. National Environmental Research Institute, University of Aarhus, DenmarkIsoprene Absolute difference [ppbV]Significance Annual averaged concentration 1990s [ppbV]Annual averaged concentration 2090s [ppbV]

10. National Environmental Research Institute, University of Aarhus, DenmarkOzone Percentage difference [%]Significance Annual averaged concentration 1990s [ppbV]Annual averaged concentration 2090s [ppbV]

11. National Environmental Research Institute, University of Aarhus, Denmark Summary and conclusions Good performance with respect to mean and seasonal variation Good performance with respect to mean and seasonal variation The climate-meteorology can be used as input to the chemical transport model The climate-meteorology can be used as input to the chemical transport model Temperature increase is the dominating factor Temperature increase is the dominating factor Increase in biogenic VOC emissions (isoprene, ozone precursor) Increase in biogenic VOC emissions (isoprene, ozone precursor) Ozone and specific humidity increases, enhanced chemical production (more hydroxyl radicals) Ozone and specific humidity increases, enhanced chemical production (more hydroxyl radicals)

12. National Environmental Research Institute, University of Aarhus, Denmark Current simulations Improved version of DEHM and ECHAM Improved version of DEHM and ECHAM A1B scenario A1B scenario Four decades (1890s, 1990s,2090s and 2190s) Four decades (1890s, 1990s,2090s and 2190s)

13. National Environmental Research Institute, University of Aarhus, Denmark Current work and near future Analysis the data from the four decades (const. emissions) Analysis the data from the four decades (const. emissions) Simulate the 1990s and 2090s with variable emissions Simulate the 1990s and 2090s with variable emissions Sophistication of the natural emitted species in the model (inclusion of particles: Terpenes) Sophistication of the natural emitted species in the model (inclusion of particles: Terpenes) High resolution over Copenhagen + surroundings (1 km x 1 km, street-scale) High resolution over Copenhagen + surroundings (1 km x 1 km, street-scale) Higher regional resolution HIRHAM-DEHM Higher regional resolution HIRHAM-DEHM

14. National Environmental Research Institute, University of Aarhus, Denmark Thank You ! Contacts: Gitte Brandt Hedegaard gbh@dmu.dk www.dmu.dk Reference: Impacts of climate change on air pollution levels with special focus on Europe and the Arctic, G.B. Hedegaard, J. Brandt, J. Christensen, C. Geels, K.M. Hansen and M. Stendel, Atmos. Phys. and Chem. Discuss., 8, 1757-1831, 2008.