The Department conducts air chemistry research in regional air quality, the atmospheric effects of aircraft, and chemistry's role in global change. These efforts involve developing state-of-the-art sensors for reactive trace gases, field observations using these sensors, and analysis with computer models of atmospheric chemistry and dynamics. A sensor for the hydroxyl (OH) and hydroperoxyl (HO2) reactive gases was developed and deployed on the NASA DC-8 aircraft for the NASA SUCCESS mission (Kansas-Oklahoma, 1996) and on the NASA SONEX (North Atlantic, 1997) field project. It will also be deployed on the NASA DC-8 aircraft for the PEM Tropics mission over the Central Pacific in early 1999. The sensor can be reconfigured for ground-based and tower-based measurements at the Department's Rock Springs site and other sites around the country. It has been used in summer 1998 as part of PROPHET, a multi-investigator tower-based study at the University of Michigan Biological Station. Sensors for other important reactive gases, such as nitrogen dioxide (NO2), are also being developed. These sensors and sensors for other gases, micrometeorology, and radiation are being used to study the interaction of chemistry and dynamics in the planetary boundary layer and the remote troposphere.
In-situ measurements of turbulence, micrometeorological, air pollution and acidic deposition variables are performed routinely at the Larson Agricultural Research Center Farm and the Scotia Atmospheric Chemistry site. The acidic precipitation data, which have been gathered since 1976 at the Scotia site, provide one of the longest records in the country. Research and development groups from several national and international laboratories come to these field sites for calibrating and checking the performance of their diverse measurement systems. In addition, various aspects of cloud physics and chemistry are investigated in the laboratory to help interpret these field measurements.