Abstract:
A spectroscopic IR and UV-vis absorption remote exhaust emission monitoring system and sensing instrument for non-invasive, multicomponent analysis of the exhaust plume emitted by in-use vehicles. The concentration of CO, CO HC, NO, N O, C H , NH , SO , Aromatic hydrocarbons, aldehydes, HONO, NO , and dust, among others and in any combination there-of, in such a mixture can be determined in real-time, or via post-processing of stored spectral data. The sensor employs an IR and a UV-vis sources, and the physically offset, collimated beams traverse the probed air column, typically a roadway, a plurality of times, before returning to the instrument. Although the IR and UV-vis beams converge at the optics opposite the instrument, they are not coaxial and, thus, do not require an optical device (i. e. , dichroic beam splitter) to separate them. The separate IR and UV-vis beams are focused on the slits of rapid spectrometers, where they are analyzed to yield wavelength-resolved spectra (i. e.