Several different molecular families are responsible for establishing the steady-state concentration levels of ozone in the atmosphere. One family of current interest is the odd nitrogen family. Within this family, the molecules of HNO₃ and NO₂ are particularly important. NO₂ provides a source of nitrogen radicals that remove ozone, while HNO₃ provides a reservoir that sequesters odd nitrogen in an inert form, with respect of ozone.

We are developing and deploying-for field atmospheric measurements-tunable infrared diode-laser-based instruments using wavelength modulation techniques. The Airborne Tunable Laser Absorption Spectrometer, dedicated to measuring the tracer N₂O, has been flying on the ER-2 high-altitude aircraft since 1986. Argus, a two-channel diode-laser instrument, measures CH₄ and N₂O on balloon platforms and unmanned aero vehicles, and has been operational since 1996. Finally, an entirely new instrument (OPTIMA) has recently been deployed on the DC-8 aircraft to measure NO₂ and HNO₃.

In conjunction with the efforts described above, we maintain a well-equipped laboratory for infrared spectroscopy to support the variety of experimental, laser testing, and spectral simulation needs required in developing and calibrating our airborne instruments.