Summary

Photochemical ozone production, or "smog", plays an important role in air quality and global climate. Reactive nitrogen compounds are key catalysts in ozone production, but the critical concentrations are well below the detection limit of commercial instruments, and measurements are sparse; very little is known of background concentrations over the Central Atlantic region of the United States. Without accurate data on nitrogen species, models cannot produce accurate simulations of ozone (O3) or hydroxyl radical (OH) concentrations. This experiment measures nitric oxide (NO), total reactive nitrogen (NOy), carbon monoxide (CO), ozone, and meteorological parameters from a mobile laboratory at an appropriate site in rural Virginia, (Shenandoah National Park) over month long periods in summer and in winter.  Included is development of a system to monitor instruments so that these measurements can be made at this and other remote locations without an expert continuously on site. To determine the origins and fates of the trace gases measured, back trajectories and a novel statistical technique were used.