This paper reports on numerical studies to evaluate the use of a series of scanning open path FTIR spectrometer measurements coupled with computed tomography to create 2D maps of chemical concentrations in air. When taking open-path measurements in the field using a scanning system, depending upon the scan rate and resolution, each measurement is taken at a different point in time. Therefore, as measurements are obtained, the concentrations of the pollutants in air are changing over time and space. The computed tomography mapping system must accurately create a series of maps from air concentration profiles that are in a state of flux. This remote sensing/computed tomography system was evaluated using a series of test maps that simulated the generation and dispersion of contaminant plumes over time. Contaminant generation rate, wind speed, and wind direction were varied to create concentration profiles that changed every fifteen seconds over several hours. A computer simulation program calculated the open-path measurements using these test maps for different interferometer scan times, and a series of reconstructed maps were obtained. The reconstructed maps were compared with original test maps and were evaluated both qualitatively and quantitatively using four measures of image quality. Results of this research provide guidance as to the range of acceptable interferometer scan times that can be used to map concentrations over time using different meteorological conditions, contamination generation rates, and number of contaminant sources.