The paper gives preliminary results from a field evaluation of a new approach for quantifying gaseous fugitive emissions of area air pollution sources. The approach combines path-integrated concentration data acquired with any path-integrated optical remote sensing (PI-CRS) technique and computed tomography (CT) technique. In this study, and open-path Fourier transform infrared (CP-FTIR) instrument sampled path-integrated concentrations along five radial beam paths, in a vertical plane downwind from the source. A meteorological station collected measurements of wind direction and speed. Nitrous oxide (N2O) was released from a controlled area source simulator. The innovative CT technique, which applies the smooth basis function minimization method to the beam data in conjunction with measured wind data, was used to estimate the total flux from the simulated area source. The new approach estimates agreed with the true emission rates in unstable atmospheric conditions and consistently overestimated the true emission rate in neutral atmospheric conditions.