Simulations of EUPHORE and field experiments using a master chemical mechanism

Introduction In recent years, a master chemical mechanism (MCM) has been developed to describe the atmospheric degradation of VOC in the atmosphere (Jenkin et al., 1997a; Saunders et al., 1997). The MCM has been developed as part of a collaborative project between the University of Leeds, AEA Technology plc and the UK Meteorological Office, and funded by the UK Department of the Environment (now the UK Department of the Environment, Transport and the Regions). The mechanism is near-explicit, and draws on the latest chemical kinetic and mechanistic results. The MCM has been validated for ozone production against the carbon bond mechanism (CBMIV), which in turn was validated against US smog chamber data (Derwent et al., 1998). The latest version of the MCM treats the degradation of 123 VOC, and can be found on the internet at http://www.chem.leeds.ac.uk/Atmospheric/MCM/ mcmproj.html). In this paper, we describe the evaluation of the MCM both through smog chamber and field experiments.