EAGER: Development of a Novel Double-resonance Fiber-laser-induced Fluorescence Instrument for Long-term, High-sensitivity, Interference-free Measurements of Hydroxyl Radical (OH)

University Of Wisconsin-Madison, Madison WI

Investigators

Abstract

This project focuses on the development of a novel method for measuring ambient hydroxyl radicals (OH) in the atmosphere, based on the use of infra-red, ultra-violet, laser-induced fluorescence (IR-UV LIF). The project is a collaborate effort with scientists in the laboratory of Professor Dr. Andreas Wahner, Director of the Institute for Energy and Climate Research at Forschungszentrum Jülich (FZJ) in Germany. Previous fundamental studies on this method have found that it is highly sensitive and free from chemical interferences, but its use has been restricted to physical-chemistry laboratories due to limitations associated with maintaining the stability of the laser in the field. The scientists will explore the coupling of a highly selective spectroscopic method to the latest advances in fiber laser technology for the development of a novel OH LIF instrument. The hydroxyl radical is the most important oxidizing species in the atmosphere. It reacts with many chemical species in air, oxidizing them and serving as a cleansing mechanism for the ultimate removal of important trace gases such as air pollutants and greenhouse gases. The novel method being developed is expected eventually to be adapted worldwide for field use, enabling long-term measurements of the hydroxyl radical. The resulting data will be critical for improving models of air quality and climate change.