Abstract

The use of pulsed laser photoacoustic spectroscopy (PAS) has many advantages in the detection of atmospheric pollutants. Sensitivities down to a few ppbv with linearity over several orders of magnitude have been demonstrated. Pulsed lasers in conjunction with nonlinear optics provide easy access to a widely tunable range of wavelengths, from the vacuum ultraviolet to the infrared. The ultraviolet wavelengths are particularly useful for the detection of pollutants such as aldehydes and SO₂. The molecules under study include NO₂, SO₂, H₂CO, and CH₃CHO. These molecules have importance as pollutants ranging from Industrial emissions to indoor air quality in homes. The technique of pulsed laser PAS is well suited in this application with high sensitivity and large dynamic range. Also, using spectral selectivity, the concentration of one component can be determined from a mixture. Thus far, detection limits of 5 ppbv in NO₂ and SO₂ and 25 ppbv in H₂CO and CH₃CHO have been achieved. Pulsed PAS spectra have been obtained in the UV to determine a measurement protocol for mixtures.

© 1985 Optical Society of America