Evaluation of seven chemistry transport models in the framework of EURODELTA III intercomparison exercise

The EURODELTA III (ED-III) exercise aimed to perform a comprehensive chemistry transport model inter-comparison study exploiting the data from four intensive measurement campaigns carried out by EMEP. The campaigns were held in different seasons (1–30 June 2006; 8 January–4 February 2007; 17 September–15 October 2008; 25 February–26 March 2009) thus allowing to test the influence of different meteorological conditions on models’ results. Seven models simulated the air quality over the whole Europe: CHIM (CHIMERE; version chim2013), EMEP (rv 4.1.3), LOTO (LOTOSEUROS, V1.8), CAMX (CAMx, v5.41 VBS), MINNI (version 4.7), CMAQ (V5.0.1) and RCG (v.2.1). Except CMAQ, all the models performed simulations over the same domain with the same horizontal spatial resolution. They also used the same input data (emissions, meteorology and boundary conditions) as much as possible. This work presents and discusses the behaviour of the models with regard to the criteria defined in the EU Directive on Air Quality 2008/50/EC for the air concentrations of PM10, PM2.5, O3, NO2 and SO2 and to the meteorological conditions. The wet deposition of sulphate (S) (WSOx), of oxidized and reduced nitrogen (N) (WNOx and WNHx, respectively) and the air concentrations of the deposited species were also investigated. Furthermore, a comparison of the capacities of air quality models to simulate carbonaceous aerosols (elemental (EC) and organic carbon (OC)) in Europe was conducted, given the diversity in modelling natural precursor emissions and formation and evolution of organic species, both natural and anthropogenic. In addition to EMEP data, the evaluation of models’ output included AirBase data and meteorological data from more than 2000 synoptic stations. The simulated concentrations of organic aerosol (OA) were compared to measurements available from two intensive measurement field campaigns carried out in a joint framework of EMEP and EUCAARI (the European Integrated Project on Aerosol Cloud Climate and Air Quality Interactions) project in 2008 and 2009