Development of an objective approach to episode selection for air quality modeling

This paper describes an objective technique for the identification of suitable, multi-day, historical episodes for air quality modeling applications. The technique includes classification of days using Classification and Regression Tree (CART) analysis and the optimal selection of multi-day episodes to meet specified criteria. The methodology considers representativeness of meteorological conditions (frequency of occurrence) as well as pollutant concentration levels. Optimization can be over multiple pollutants (for integrated modeling applications) or multiple areas (for regional modeling applications).

Example applications of this technique for (1) the selection of modeling periods for the integrated assessment of ozone, visibility, and acid deposition for the Southern Application Mountains Initiative (SAMI) and (2) the selection of modeling periods for regional-scale modeling of 8-hour ozone issues along the eastern Gulf Coast, will be described.