Indirect Flux

The indirect flux method is used for emission assessments of gases that cannot be directly measured by (SOF or SkyDOAS or other sensors). Indirect flux relies on measured gas-ratios in the same plume as quantified by SOF. The mass concentrations (mg/m3) are measured downwind, usually with a mobile monitor (MeFTIR or MeDOAS). From the plume integrated mass ratio of the “tracer-gas” (measured by SOF) and the “target-gas”, the emission rate of the “target-gas” can be retrieved. The method assumes that the target gas and the tracer gas have the same origin and are dispersed similarly. Parallel measurements of SOF and MeFTIR/MeDOAS are advantageous.