1. Chemical mechanisms within CHIMERE present and future Matthias BEEKMANN

2. The standard mechanism: MELCHIOR describes : Photo-oxidant formation in polluted and clean environments, including the free troposphere Can be coupled with inorganic and organic aerosols modules (NH3, HNO3, SO2-> H2SO4, VOC + OH)

3. EMEP mechanisms, 70 compounds 135 reactions Simpson et al., 1992 Extended MELCHIOR 82 compounds, 338 reactions Lattuati, 1997 Reduced MELCHIOR ~40 compounds, ~120 reactions Derognat, 2002 Schmidt et al., 2001 Heterogeneous réactions from Jacob et al. 2000 Bessagnet et al., 2004 MCM Master - Chemical Mechanism University of Leeds Jenkins et al. 1997 Reduction Operator approach Peroxyles/peroxydes Nitrates Updating of aromatic and biogenic VOC oxidation

4. MELCHIOR treatment of VOC’s 8 primary VOC’s (explicit or familily representatves) Methane Ethane N-butane Ethene Propene Ortho-xylene Isoprene  -pinene 12 (10) secondary VOC’s (explicit or familily representatves) Formaldehyde Acetaldehyde Methyl-ethyl-ketone Glyoxal Methyl-glyoxal Dimethyl-glyoxal, 4-oxo-2-penatanal 5-methyl-3H-furan-2-one Methyl-vinyl-ketone Methyl-acroleine (Methanol) (Ethanol)

5. Comparison with RACM

6. Comparaison entre MELCHIOR / EMEP / RACM (2)

7. Comparaison entre MELCHIOR / EMEP / RACM (3)

8. Comparaison entre MELCHIOR / EMEP / RACM (4) E NOx = 0.32 ppb/ day E COV = 0.44 ppbC/day

9. SAPRC99 (Carter) “A detailed mechanism for the gas-phase atmospheric reactions of VOCs and NOx in urban and regional atmospheres” (documentation of the SAPRC99 chemical mechanism for VOC reactivity assessment, Carter, 2000) -Used to “determine the absolute and relative ozone impact of the many types of VOCs that can be emitted into the atmosphere, and for other control strategy and research applications” -Used to calculate the various ozone reactivity scales developed by Carter (MIR, 1994) 82 species, ~ 30 (O)VOC 241 reactions Representation of the radicals chemistry Detailed speciation of VOCs and RO2 Implantation in CHIMERE FUTURE POSSIBILITIES: