The challenge of quality assurance for emission flux measurements of large area sources by optical remote sensing.

Monitoring the emissions flux of contaminant gases from large area sources requires measurement of concentrations from an optical remote sensing device and reconstruction of the plume. Path integrated concentrations are determined using multiple optical beam paths. The spatial distribution of concentrations is generated for a plane perpendicular to the direction of the wind. Estimates of the emission flux are determined by integrating the product of the calculated concentrations and wind speeds over the plane. No standard method exists for the complete process, defensible estimates of the uncertainty of the final emission flux have not yet been developed, and a data validation procedure is needed. Auditors are challenged to configure an adequate performance evaluation standard that is representative of a large area source.