CRF Researchers Develop New Approach for Low-Cost Emissions Diagnostics

Modeling and experiments show that it is feasible to perform multiple-species detection at sub-ppm levels with a low-resolution broad-band infrared laser. Target measurement species include CO₂, CH, N₂O, NO₂, SO₂, HCl, and CH₄, among others, simultaneously, and without process treatment or dehumidification of the exhaust sample—potentially reducing current emission-monitoring costs and the need for extensive sample preparation. Both the photoacoustic spectroscopy and cavity ring-down methods show promise in this regard.

The photoacoustic spectroscopy method in particular is surprisingly sensitive despite its extremely simple configuration, and has the potential to offer an extraordinarily cost-effective platform for multiple-component trace-gas measurements at the sub-ppm level. Due to the dramatic improvement in the measurement sensitivity expected from an increase in the resolution, development of a novel infrared spectrometer has been undertaken.

Significant progress toward developing the first infrared dual-etalon cavity ring-down spectrometer has been achieved, and future work holds the potential to develop revolutionary capabilities in measurement sensitivity for multiple-component systems with this instrument.