Abstract

Infrared detection of air pollutants has been extended to the parts-per-billion sensitivity range. The increased detection sensitivity results from the use of the scanning Michelson interferometer, cooled solid state detectors, the fast minicomputer, and the multiple pass long path cell. Forming ratios of spectra with the aid of the computer extracts obscure information and minimizes the interferences of atmospheric water and carbon dioxide. Almost all of the significant gaseous pollutants can be measured by the method described, even at concentrations smaller than one part pollutant to one billion parts air.

Sub-parts-per-billion level detection of dimethyl methyl phosphonate (DMMP) by quantum cascade laser photoacoustic spectroscopy

Anadi Mukherjee, Ilya Dunayevskiy, Manu Prasanna, Rowel Go, Alexei Tsekoun, Xiaojun Wang, Jenyu Fan, and C. Kumar N. Patel
Appl. Opt. 47(10) 1543-1548 (2008)

Sub-part-per-billion monitoring of nitric oxide by use of wavelength modulation spectroscopy in combination with a thermoelectrically cooled, continuous-wave quantum cascade laser

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Air pollution measurement by Fourier transform spectroscopy

Philip L. Hanst
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Opt. Lett. 40(13) 2933-2936 (2015)

Part-per-billion level photothermal nitric oxide detection at 5.26 µm using antiresonant hollow-core fiber-based heterodyne interferometry

Karol Krzempek
Opt. Express 29(20) 32568-32579 (2021)