Measurement of NO, NO2 and HNO3 Using a Tunable Diode Laser System. Second Year Report. Phase 2 Modification to Permit Automated Simulataneous Multi-Species Monitoring and Feasibility Study of Extension to H2O2, CH2O and HONO

摘要

The tropospheric air monitoring system (TAMS), which was developed by Unisearch Associates, Inc. under contract to the Coordinating Research Council, has been modified to permit nearly simultaneous monitoring of two or more species. The system was developed to allow for computer control of the laser systems and computer data acquisition which could provide real time data analysis. The system can monitor at least two of NO, NO2, and HNO3 nearly simultaneously (within five seconds) in the troposphere at sub-part-per-billion-by-volume (ppbv) levels. A second task in the contract was to perform studies on additional species to determine the feasibility of using the TAMS in their detection. This has been done for three species: H2O2, CH2O, and HONO. Lasers have been obtained for all three species, and regions in their absorption spectrums free from interferences due to other tropospheric constituents have been identified. Detection limits of less than a few ppbv have been determined for H2O2 and CH2O and have been measured in doped synthetic air and in ambient laboratory air.