Ultrasensitive Airborne Instrumentation for the Quantification of Aerosol Precursors

Carbonaceous aerosols warm the atmosphere while sulfate aerosols reflect sunlight, moderating climate warming. In laboratory experiments, sulfate aerosol formation depends, in a strong, non-linear manner, on ammonia concentrations. There are limited field-studies, and uncertainties are partially responsible for limitations in predicting aerosol nucleation globally. Improving scientific understanding of aerosol formation is crucial and timely because of the need to better characterize climate sensitivities and assess warming mitigation options that involve the use of aerosol injections into the stratosphere. Current ammonia analysis instrumentation is expensive, heavy, and requires cryogens. This project will address these problems by developing ultrasensitive airborne and terrestrial instrumentation capable of rapidly quantifying trace levels of ammonia, and other critical aerosol precursors. The Phase I project demonstrated technical feasibility by fabricating an Off-Axis ICOS analyzer that accurately measured ammonia in trace concentrations. The Phase I results were used to design a Phase II prototype. Commercial Applications and other Benefits as described by the awardee: The Phase II project will develop and deliver two analyzer systems capable of making field measurements of ammonia and other aerosol precursors at ambient levels. The first instrument will be optimized for ammonia flux measurements and delivered to Lawrence Berkeley National Laboratories for field studies. The second instrument will be customized for airborne deployment aboard a DOE research aircraft and delivered to Pacific Northwest National Laboratory. Final Phase II work will include measuring and analyzing preliminary data for both terrestrial and aerial deployments in conjunction with DOE researchers.