A review of the development and application of the CALINE3 and 4 models

A description of the California Line Source Dispersion Model, CALINE, is given along with a brief history of its development. The model is based on the Gaussian plume methodology and is used to predict air pollutant concentrations near roadways. Predictions can be made for carbon monoxide, nitrogen dioxide and suspended particulates.

There are two versions of the CALINE model in current use. CALINE3, published in 1979, replaced the virtual point approximation contained in earlier versions of the model with an equivalent finite line source representation and added a multiple link option. CALINE4, published in 1984, incorporated flexible input/output options including an option for modeling air quality near intersections. It also includes dispersion algorithms to account for vehicle-induced thermal turbulence and wind direction variability.

CALINE4 is verified using results from five separate field studies. Comparisons to CALINE3 indicate modest improvements in the accuracy of the newer version.