3D Photochemical Dispersion Models for Secondary Air Pollutant Study: from Input Data Preparation to Model Performance Evaluation

Secondary air pollutants are formed through series of complex reactions occurred in the atmosphere under favorable meteorological conditions. Commonly known species are ozone and secondary aerosols, secondary inorganic and organic aerosols. Through its complexity, varieties of three dimensional (3D) photochemical dispersion models have been developed globally to simulate formations and dispersions of the secondary as well as the primary pollutants in the atmosphere. CMAQ and CAMx are the state of the science models under “one atmospheric approach”, noncommercial and open-source software. These characteristics are attracted and challenged for future air quality management via model simulations. Applications of CMAQ and CAMx are normally based on several steps: preparation of emission input, modeling set-up and model performance evaluation. This article presents the systematic procedures involved with the use of 3D photochemical models starting from theoretical principles for formation of secondary air pollutants, types of photochemical models and its associated physical and chemical modules, input data preparation including reviews on available emission inventories and lastly statistical methods for model performance evaluation.