Simultaneous Measurement of Vaporous and Aerosolized Threats by Active Open Path Ftir

The Environmental Protection Agency’s open-path Fourier transform infrared (OP-FTIR) activities include passive and active measurements in several stack and fugitive emission monitoring applications. Extensive research has been devoted during the past two years to evaluate and validate various OP-FTIR technologies for the identification and detection of toxic industrial compounds and chemical warfare agents, primarily in the gas phase. This paper emphasizes the superiority of the active OP-FTIR system over the passive system in detection levels and data quality, and disputes misconceptions that are generally well accepted for FTIR technologies. Additionally, a new approach for detection and identification of aerosolized threats using an active modulated OP-FTIR is described. Revisiting the use of active OP-FTIR techniques is recommended as recently many non-battlefield detection applications have emerged.