MEASUREMENT TECHNIQUES INVESTIGATED FOR DETECTION OF HYDROGEN CHLORIDE GAS IN AMBIENT AIR

摘要

As part of NASA s tropospheric research program on the effects of solid rocket motor and launch vehicle effluents on ground-level air quality, the Langley Research Center initiated in 1972 a program to develop an in situ technique to monitor low concentrations of hydrogen chloride gas in ambient air. The program required instrumentation capable of measuring concentrations of hydrogen chloride gas in parts per million or less with response times from a few seconds to less than a minute. This paper summarizes the results of the instrument development program, presents the status of each technique considered, and summarizes the available labo¬ratory data for each technique. This paper is not an all-inclusive summary of hydrogen chloride detection techniques. Nine basic techniques are discussed, rang¬ing from concentration (parts per million) to dosage only (parts per million-seconds) measurement techniques. Data for each technique include lower detection limit, response time, instrument status, and in some cases, specificity. Several tech¬niques discussed can detect ambient hydrogen chloride concentrations below 1 part per million with a response time of seconds.