Emission rate apportionment from fugitive sources using open-path FTIR and mathematical inversion

This paper presents a detailed new methodology to address emissions from non-homogeneous fugitive gaseous air pollution sources. An open-path FTIR system is employed in a new field configuration, in which the main measurement path located downwind from the source and segmented into several secondary paths. The segmentation can be performed by retroreflectors or black bodies situated along the main measurement path, for a unistatic system or bistatic system respectively. An inversion technique is used, in conjunction with plume dispersion modeling techniques to reconstruct the emission rates distribution from different strips of the fugitive source. A field study to evaluate and validate the proposed methodology was conducted. In the validation field study, large and relatively cold black bodies ( 100°C) were successfully used as the sources of infrared radiation. Emission rates from three controlled emission point sources of SF6 were reconstructed by applying the suggested methodology, and agreed quite well in most runs of the field study