The Use of MM5-CMAQ Air Pollution Modelling System for Real-Time and Forecasted Air Quality Impact of Industrial Emissions

The sophistication of air pollution modeling systems has continued to increase in the last decade. Nowadays, the complex numerical mesoscale meteorological and chemical dispersion models have become very robust tools which are quite sensitive to small changes in the atmospheric process. The use of these tools as air quality management systems is becoming more and more common at urban and regional levels in many parts of the world. In this contribution we have applied the MM5-CMAQ modeling system in the framework of OPANA V3 with emission data sets produced by EMIMO to evaluate the capability of the system to be used as a tool to determine in realtime and forecasting mode the individual impact of five different virtual industrial sources located at the south-east direction of Madrid (Spain) city. The system has been developed for two different scenarios for each single industrial source: OFF (complete switching off the emissions, 100%) and OFF50 (reducing the expected emissions from each single industrial source by 50%). The simulations are carried out over 120 hours, and the emission reduction strategies are applied for the last 48 hours in a way that when the system is used in real-time and forecasting mode in daily operational use, the information is ready to be applied 12 – 20 hours before the hour 96 of the simulation. So, implementation of the emission reduction strategy — in case of need — can be done for such a single industrial plant in such a period of time. The results of 11 simulations (ON + 5xOFF + 5xOFF50) are analyzed by developing a robust post-processing tool which will report us about the time, location (grid cell) and eventually the industrial plant (or plants) which should apply the reported emission reduction scenarios. The modeling system has been mounted with two domains for MM5 with 81 and 27 km spatial resolutions and also with other two domains with 9 km and 3 km spatial resolutions. The CMAQ model has been mounted according to MM5 architecture just for the domains with 9 and 3 km spatial resolutions. Analysis of the air quality impact of industrial sources is prepared for the domains with 9 km and 3 km spatial resolutions. The system has proved to be robust and sensitive enough to be used in a reliable way. The computer time for all exercises is about 140 hours on a PIV-3,06 Ghz. In real operational mode, it can be reduced to 14 hours or less (daily operation) with a 20 PC cluster.