Open-Path Optical Ammonia Monitor

The effects of aerosol particles on climate are the most uncertain aspects for quantifying the impact of human activities on future climate changes. Although ammonia plays a critical role in the formation and identity of atmospheric aerosol particles, ammonia is incredibly difficult to measure due to its low concentration in the atmosphere. Consequently, widespread and fast measurements of gas phase ammonia aerosols are greatly lacking. In addition, measurement artifacts are created by the challenges of sampling such a ¿sticky¿ gas. This project will develop a tunable, external-cavity, quantum-cascade light source for measuring ammonia in an open-path setup; no inlets or sampling lines will be needed. Patented, singular-value decomposition algorithms will be used to remove the effects of other atmospheric trace species on the spectral ammonia peak. Commercial Applications and other Benefits as described by the awardee: By contributing to the identification of aerosol particles, and by providing information on how these particles nucleate and grow, this technology could help constrain the effects of aerosols on climate. In addition, the technology should have commercial application in the biomedical field (kidney analysis) and semiconductor industry (wafer fabrication).