SGER: High Time Resolution Measurements of Peroxy Acyl Nitrates at Mt. Bachelor Observatory During Intercontinental Chemical Transport Experiment Phase B (INTEX-B)

University Of Washington, Seattle WA

Investigators

Abstract

A newly constructed chemical ionization mass spectrometer (CIMS) capable of detecting a range of peroxy acyl nitrates (RC(O)OONO2 where R is an organic moiety) with high sensitivity and 1 second time resolution will be deployed at the Mt. Bachelor Observatory (MBO) in central Oregon during a field campaign planned for April 15 - May 15, 2006. The MBO intensive will overlap with C-130 aircraft observations from Seattle, WA, one component of the Intercontinental Chemical Transport Experiment (INTEX-B), which is in turn part of the broad scale Megacity Initiative: Local and Global Research Observations (MILAGRO), a study of the effects of emissions, chemical transformations, and transport from large urban areas. Peroxy acyl nitrates are labile reservoirs of nitrogen oxides (NOx = NO + NO2), and make up a substantial fraction of total oxidized nitrogen (NOy) in the remote troposphere. Their formation in polluted regions and subsequent long-range transport and decomposition is the only viable mechanism by which anthropogenic emissions in Asia could affect NOx levels and ozone photochemistry in the Pacific troposphere and on the west coast of the United States. Deployment of this CIMS instrument will enhance the observational suite planned by the National Aeronautics and Space Administration (NASA) and MBO by providing real-time measurements of several peroxy acyl nitrates and will allow a side-by-side comparison of two different instruments based on fundamentally different techniques for peroxy acyl nitrate measurement. The data will aid in understanding the effects of long-range pollution transport on the background chemistry and composition of remote regions of the atmosphere. This research will also broaden the educational experience of graduate students and post-doctoral fellows.