MRI: Development of a Cavity Ring-Down Sensor for Real-Time Measurement of Atmospheric Mercury Concentrations and Fluxes

Nevada System Of Higher Education, Desert Research Institute, Reno NV

Investigators

Abstract

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). This project will develop a real-time, sensitive sensor for measurement of atmospheric mercury (Hg) to resolve uncertainties in atmospheric Hg measurements imposed by low temporal resolution of current sensors. Based on a laboratory prototype Hg sensor developed at the Desert Research Institute (DRI), this project aims to (1) develop a fast-response cavity ringdown sensor with open- and closed-path cavities to measure atmospheric Hg; and (2) deploy and field-test the sensor, including the first application for Hg flux measurement by means of eddy covariance. The goal is a sensor that is stable, easy to deploy, and safe to operate at ground-based and high-elevation research stations. Building on an existing prototype, a sensor will be developed with fundamental design improvements and key technical features, including improved mirror reflectivity, high-frequency wavelength tuning for differential on/off absorption line measurement, automatic wavelength locking, and optimized design, to significantly improve detection limits and facilitate field deployments. The new sensor for measurement of atmospheric Hg concentrations and fluxes will enable significant advances in knowledge of the distribution and dynamics of atmospheric Hg, the primary source of Hg inputs to freshwater aquatic ecosystems. Better quantification of Hg sources, sinks, transformations, and transport patterns will be critical for regulatory agencies to protect humans and ecosystems from this potent toxin. The project will involve high school, undergraduate, and graduate students and post doctoral scholars. An educational component will be targeted at underrepresented groups through participation in existing NSF-funded projects that will (1) provide research experiences for a diverse group of undergraduate students from several partner institutions, including several Historically Black Universities and Hispanic-serving institutions; and (2) enhance participation in workshop programs, mentoring, and promoting collaboration with women faculty in atmospheric science and meteorology. Further educational activities will include strengthening current partnerships with local high schools and showcasing the sensor development in an atmospheric instrumentation course at the University of Nevada, Reno. Outreach and dissemination to the scientific community will be accomplished through publications and presentations. The general public will be reached through news releases, DRI institutional publications, and Web sites. Technology transfer for the instrument being developed will be pursued.