Introduction to Air Quality Modeling

The goal of AQ Modeling is to supply pertinent information for decisions to be made within the framework of Air Quality Management Systems, especially in connection with control strategies. The fundamental problem which has to be solved is to calculate air concentrations of one or more species in space and time as related to the independent variables such as the emissions into the atmosphere, the meteorological variables, and parameters which describe removal and transformation processes. All these independent variables can be functions of space and time, but need not all be considered. If these air concentration fields are calculated as functions of space and time one can obtain from them hourly, daily, monthly or yearly averages or frequency distributions of concentrations at a given point in the field, which in most cases will be at the surface. This aim is achieved by a system which relates quantitatively the concentrations to the other parameters by mathematical and/ or physical methods. Such a system is called a “model”.