Development of Simple Dispersion Model for Simulation of Air Toxics in Urban Areas Available to Purchase

The paper details the development of an air dispersion model, Simflx7, a computer model that requires a minimum amount of input data while still allowing for the use of both a ground reflection and a reflection from a confining layer above. Simflx7 is based on the classical Gaussian approach and can accommodate gridded independently varying emission sources and calculates the result of all sources emissions on multiple receptors. The project used “real world” data from the Seattle-Tacoma basin for the model demonstration and validation. A gridded inventory for an area of approximately 154 miles by 166 miles was used that has been developed jointly by the Washington State University and the Washington Department of Ecology. The receptor data used for model verification were from six receptor sites located in the greater Seattle area and 24-hour average data collected, and analyzed by Washington State University Laboratory for Atmospheric Research. These data created a unique opportunity for the validation of a model using “real world” data. Typical statistical measures were used to judge model performance against the observations.