The Use of MM5-CMAQ-EMIMO Modelling System (OPANA V4) for Air Quality Impact Assessment: Applications for Combined Cycle Power Plants and Refineries (Spain)
Since 2000 the EPA Models-3 Community Multiscale Air Quality Modelling System (CMAQ) has become in one of the state-of-the-art air quality tools to perform a full analysis of the air concentrations in a determined domain in space and time. The CMAQ modelling tool incorporates several chemical mechanisms, several numerical solvers, several boundary layer parameterizations, etc. and the user has to select the best option according to their experience and knowledge to perform any air quality simulations in historical and/or forecasting mode. The MM5 meteorological mesoscale model and/or the new generation of mesoscale meteorological models based on WRF model can be used as input for CMAQ. Additionally, our laboratory has developed along the last ten years a sophisticated emission model which provides with the corresponding spatial and temporal resolution, the emission data required by CMAQ to perform the full simulations. This system — MM5-CMAQ-EMIMO (OPANA V4) – can be used to forecast air concentrations in space and time or to simulate different periods of time in the past. In order to perform an air quality impact assessment of an industrial plant such as a combined cycle power plant or a refinery, we should run our air quality modelling system for a period of time in the past according to the EU Air Quality Directives (and also US EPA Regulations for non-EU applications). The EU Directives related to the limits in air concentrations are concerned with a number of exceedances of a specific concentration along one year. There are limits for 8-hour, days and year. In this contribution we show the methodology to be used to fulfil the EU Directives for different applications – combined cycle power plants and refineries — in Spain and some results. The use of the system for one-year period to adapt the results to the actual legislation is presented.