CO(2) laser absorption cross-section data are reported for acrolein, styrene, ethyl acrylate, trichloroethylene, vinyl bromide, and vinylidene chloride. These data indicate that sub parts per billion level, interference-free detection limits should be possible for these compounds by the CO(2) laser photoacoustic technique. Photoacoustic detectabilities below 40 ppb should be possible for these compounds in the presence of ambient air concentrations of water vapor and other anticipated interferences. These compounds are also found not to be important interferences in the detection of toxic hydrazine-based rocket fuels by CO(2) laser spectroscopic techniques.

A photoluminescence technique, which detects lead and antimony in gunshot residue, was evaluated for use in investigations of apparent gunshot suicides. The study was conducted in conjunction with forensic science laboratories in five U.S. cities. Samples were collected by the adhesive lift method from the backs of the hands of 67 gunshot suicide victims, 41 subjects who died of other causes, and 31 live subjects with high occupational exposure to lead and antimony. Tentative simultaneous threshold levels of 0.85μg for lead and 0.01 μg for antimony were selected as criteria for presuming the presence of gunshot residue on samples from the hands of these suicide victims. Although blood decreases the detectability of lead and antimony in the samples, 48% of the suicide cases involving handguns other than .22 revolvers exceeded the threshold levels for both lead and antimony. Methods are suggested for eliminating the effects of blood, which should significantly increase the success rate for cases involving these guns. A much lower success rate was obtained for cases involving .22 revolvers and long guns, as expected from the sparse amounts of residue found in previous test firings of these guns.

Absorption cross-section data are reported for the toxic rocket fuels hydrazine, monomethylhydrazine, and unsymmetrical dimethylhydrazine (UDMH), as well as for their selected air oxidation products dimethylamine, trimethylamine, and methanol at up to seventy-eight CO(2) laser wavelengths each. These data are important for the assessment of the capability of CO(2) laser-based spectroscopic techniques for monitoring low levels of hydrazine-fuel vapors in the ambient air. Interference-free detection sensitivities of <30 ppb have been demonstrated for UDMH using a laboratory photoacoustic detection system.

Absorption coefficient data are reported for acrolein, styrene, ethyl acrylate, trichloroethylene, vinyl bromide, and vinylidene chloride at up to seventy -two CO2 laser wavelengths each. These compounds are toxic industrial substances for which improved ambient air detection methods are desired.Absorption data for these compounds are needed to determine their detectabilities by CO2 laser-based photoacoustic, long -path absorption, and laser radar (lidar) techniques.The absorption data obtained for these compounds indicate that sub parts -per -billion (ppb) level, interference -free detection limits should be possible for these compounds by the CO2 laser photoacoustic technique.CO2 laser photoacoustic detectabilities of 40 ppb or less should be possible for these compounds in the presence of expected ambient air concentrations of water vapor and other anticipated interferences.In addition, absorption data on the first four compounds are needed to assess the capability of using CO2 laser spectroscopic techniques to detect low levels of the toxic hydrazine -based rocket fuels in air samples containing these compounds as interferences. The absorption data obtained for these four compounds indicate that the hydrazine -fuels should be detectable by the CO2 laser photoacoustic technique at concentrations below proposed workplace standards for hydrazines as low as 30 ppb in the presence of expected airborne concentrations of these compounds together with other expected interferences.

This report describes recent work performed at The Aerospace Corporation to determine the capability of the COT laser photoacoustic technique to detect the rocket fuels hydrazine, monomethylhydrazine (MM4), and unsymmetrical dimethylhydrazine (UDHE) at low parts-per-billion (ppb) levels in the ambient air in real time. These compounds are highly toxic and recent studies indicate that they may also be carcinogens. Revised OempaIeional Safety and Reaith-*dmlnistration (OSgA) regu-lationa are expected that will reduce the maximum allowable concentrations of Do