Field evaluation of a method for estimating gaseous fluxes from area sources using open path Fourier transform infrared

This paper describes results from the first field experiment designed to ev aluate a new approach for quantifying gaseous fugitive emissions of area ai r pollution sources. The approach combines path-integrated concentration da ta acquired with any path-integrated optical remote sensing (PI-ORS) techni que and computed tomography (CT) technique. In this study, an open-path Fou rier transform infrared (OP-FTIR) instrument sampled path-integrated concen trations along five radial beam paths in a vertical plane downwind from the source. A meteorological station collected measurements of wind direction and wind speed. Nitrous oxide (N2O) was released from a controlled area sou rce 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 sour ce. The new approach estimates consistently underestimated the true emissio n rates in unstable atmospheric conditions and agreed with the true emissio n rate in neutral atmospheric conditions. This approach is applicable to ma ny types of industrial areas or volume sources, given the use of an adequat e PI-ORS system.