James J. Schwab Atmospheric Chemistry Research Professor Office: CESTM L107 Phone: (518) 437-8754 Fax: (518) 437-8758 Email: schwab@asrc.cestm.albany.edu

B.Sc. (Physics), 1977, University of Minnesota

Ph.D. (Chemical Physics), 1983, Harvard University

Research Fellow, 1983-1988, Harvard University

Research Interests:

My primary research involves the measurements of atmospheric trace gases; especially those involved in tropospheric ozone production and airborne particulate matter. I have also done work in instrument development, surface-atmosphere exchange of trace gases, atmospheric radiation, and chemical kinetics of radical-molecule and radical-radical reactions.

Advances in Atmospheric Science have occurred as a result of our ability to observe and measure, with increasing accuracy, the properties of the atmosphere. This is true in dynamic meteorology, in physical meteorology, and in my field, atmospheric chemistry. Many of the most important chemical species are only present at the part-per-billion (ppb) or part-per-trillion (ppt) level, so it is crucial that we make accurate and repeatable measurements down to these levels.

In 1995 we outfitted a New York State Department of Environmental Conservation owned RV with gas analyzers for O3, CO, NO-NOX, NO-NOY, SO2, and hydrocarbons; and sited this mobile air monitoring station near Corning in southwestern New York. The station also makes routine meteorological measurements of wind speed, wind direction, temperature, humidity, precipitation, solar, and UV radiation. This station was part of a network of 9 similarly equipped sites throughout the Northeastern US involved in a coordinated program to study tropospheric ozone pollution. Using extensive data from many sites will allow us to better determine the sources of ozone pollution. In 1999 the RV was replaced with a prefabricated air monitoring shalter, and we began to measure airborne particulate matter (aerosols or PM2.5) in addition to the gaseous pollutants and precursors.

Research Site at Pinnacle State Park	Air Inets on Roof of Shelter	Instrument Rack with Gas Analyzers

Another major area of research in my group is aimed at developing instrumentation for the measurement of chemical composition of the atmosphere, primarily the more reactive species. In particular, we have worked on Laser Absorption Spectrometers for methane (CH₄) and for hydrogen peroxide (H₂O₂). These instruments use mid-infrared gas lasers, multipass absorption cells, and frequency modulation detection techniques. After a period of laboratory development, the new instruments will be used for measurements in the field.

The buildup of species such as CO₂ and CH₄ in the atmosphere, and the implications for atmospheric chemistry and global warming are important and controversial topics. We have also worked at applying fast chemical sensors in conjunction with micrometeorological tower measurements to determine surface atmosphere exchange fluxes. Our understanding of the cycling of many trace species through the atmosphere depends on such measurements.

Previous work included a project comparing satellite and in situ measurements of stratospheric water vapor. Water vapor is important throughout the atmosphere for its physical, radiative, and chemical properties; and a thorough understanding of its distribution is essential. We used the more precise in situ measurements to place the global satellite measurements on a surer footing.

Selected Publications

"What Constitutes a Valid Intercomparison of Satellite and in situ Stratospheric H2O Measurements?" J.J. Schwab, R.-J. Pan, J. Zhang. J. Geophys. Res., 101, 1517-1528, 1996.

"In Situ Measurement of Water Vapor in the Stratosphere with a Cryogenically Cooled Lyman-Alpha Hygrometer", J.J. Schwab, E.M. Weinstock, J.-B. Nee, and J.G. Anderson. J. Geophys. Res., 95, 13,781-13,796, 1990.

"A Test of Modeled Stratospheric HOX Chemistry: Simultaneous In Situ Measurements of OH, HO2, O3, and H2O", P.O. Wennberg, R.M. Stimpfle, E.M. Weinstock, A.E. Dessler, S.A. Lloyd, L.B. Lapson, J.G. Anderson, and J.J. Schwab. Geophys. Res. Lett., 17, 1909-1912, 1990.

"Kinetics and Mechanism of the OH + HO2 Reaction", J.J. Schwab, W.H. Brune, and J.G. Anderson. J. Phys. Chem., 93, 1030-1034, 1989.

Student Theses Advised

Kathy Vertefeuille, "A Study of Tropospheric Chemical Species at a Rural Site in Southwestern New York", M.S. Thesis, December, 1997

Rong-Juinn Pan, "Comparison of SAGE II and In Situ Stratospheric Water Vapor Profiles", M.S. Thesis, May, 1992.