Simultaneous detection of multiple greenhouse gases using open-path spectrometers

Spectroscopic techniques in the infrared and ultraviolet spectral regions may efficiently meet increasing measurement challenges in real-time detection of greenhouse gas concentrations and fluxes in the troposphere. Open-path spectrometers offer several advantages over conventional point monitors, such as spatially-averaged gas concentrations over pathlengths of 50-1000 meters, and detection of multiple gases simultaneously and in real time. Current capabilities in open-path IR and UV spectrometers are summarized as well as the use of inert tracers to relate measured concentrations to emission flux. Results from a monitoring campaign in Arlington, TX, in which the concentrations of CO, CO₂, CH₄, and O₃ were continuously monitored, are also presented.