Dr. Brad Baker

http://www.csus.edu/indiv/b/bakerb/

Chem 31 – Quantitative analysis
Chem 133 – Instrumental analysis
Chem 230 – Separation methods in chemistry
Chem 231 – Chemical separations laboratory

Plants are the major source of volatile organic compounds (VOC) to the atmosphere. These compounds, once emitted, play a major role in the chemistry of the lower atmosphere. Of major interest is the role that biogenic VOCs play in the production of tropospheric ozone, a major component of photochemical smog. This phenomenon occurs when VOCs mix with elevated concentrations of nitrogen oxides (which are primarily anthropogenic), in the presence of sunlight. Also of major interest is the contribution that biogenic VOCs make to natural background organic aerosol. Understanding what effects the composition of atmospheric aerosols is necessary in order to understand aerosols' impact on climate change, human health, and atmospheric visibility. Other important environmental issues that are influenced by biogenic VOCs are carbon cycling and atmospheric oxidant production and loss.

My research involves quantifying and understanding emissions of biogenic VOCs from various types of plants. Currently, this includes emissions from ecosystems in China, and emissions from agricultural plants. A broad range of ecosystems exist in China with unique vegetation for which no emissions data has ever been reported. Considering that one sixth of the world's population lives in China, the effects of biogenic emissions from these landscapes have the potential to affect a large population. In addition, changes in land use, which is occurring at a fast pace in China, leads to changes in vegetation cover, and can have a large influence on the types and amounts of biogenic VOCs emitted. Over the past several years, we have been traveling to various sites in China including tropical forests and grasslands to determine biogenic emission rates, and relate these emissions to various land use practices. Emissions of biogenic VOCs from agricultural plants have been largely ignored. This is because initial measurements made years ago indicate that crop plants do not emit large amounts of VOCs. However, in some regions, crop plants may be the largest source of 'naturally' emitted VOCs, and new measurement technology now allow us to measure certain VOCs that would have been overlooked in the past. In addition to these measurement campaigns, my lab is also developing new methods for biogenic VOC analysis. We are working on building small, lightweight, and power conserving instrumentation that can be taken to remote areas and generate accurate data.

We are also exploring the use of novel techniques for the sampling and analysis of biogenic VOCs, such as the use of solid phase microextraction fibers, and fluorescence spectroscopy.

Geron, C., S. Owen, A. Guenther, J. Greenberg, R. Rasmussen, J.-H. Bai, Q.-J. Li, and B. Baker, (2006), Volatile organic compounds from vegetation in southern Yunnan Province, China: Emission rates and some potential regional implications, Atmos. Environ., 40, pp 1759-1773.

Karl, T., P. Harley, A. Guenther, R. Rasmussen, B. Baker, K. Jardine, and E. Nemitz, (2005), The bi-directional exchange of oxygenated VOCs between a loblolly pine (Pinus taeda) plantation and the atmosphere, Atmos. Chem. Phys., 5, pp 3015-3031.

Stroud, C., P. Makar, T. Karl, A. Guenther, C. Geron, A. Turnipseed, E. Nemitz, B. Baker, M. Potosnak, and J. D. Fuentes, (2005), Role of canopy-scale photochemistry in modifying biogenic-atmosphere exchange of reactive terpene species: Results from the CELTIC field study, J. Geophys. Res., 110, D17303, doi:10.1029/2005JD005775.

Baker, B., J.-H. Bai, C. Johnson, Z.-T. Cai, Q.-J. Li, Y-F. Wang, A. Guenther, J. Greenberg, L. Klinger, C. Geron, and R. Rasmussen, (2005), Wet and dry season ecosystem level fluxes of isoprene and monoterpenes from a Southeast Asian secondary forest and rubber tree plantation, Atmospheric Environment, 39, pp 381-390.

Klinger, L. F., Q.-J. Li, A. B. Guenther, J. P. Greenberg, B. Baker, and J.-H. Bai, (2002), Assessment of volatile organic compound emissions from ecosystems of China, J. Geophys. Res., 107, pp 4603-4624.

Geron, C., A. Guenther, J. Greenberg, H. Loescher, D. Clark, and B. Baker, (2002), Biogenic Volatile Organic Compound Emissions from a Rain Forest in Costa Rica, Atmospheric Environment, 36, pp 3793-3802.

California State University, Sacramento | 6000 J Street | Sacramento, CA 95819 | (916) 278-6011