PROGRAM TITLE:	Greenhouse Gas Dynamics (GGD)
ACTIVITY STREAM:	Process, Assess, Observe, Model
SCIENCE ELEMENT:	Biogeochemical Dynamics/Mitigation


SCIENTIFIC MERIT:  The "Greenhouse Gas Dynamics" (GGD) program 
supports research needed to understand:  (1) the interactions of greenhouse 
gases (GHGs) with light, other atmospheric gases, surfaces, and other relevant 
substances; and (2) the complex chemical processes, both natural and 
industrial, which lead to GHG production and release.  In order to carry out 
the analyses needed to define, model and predict environmentally critical 
interactions, development of new physical and chemical tools will be 
required.  Adsorption, photochemistry, and bulk reaction between GHGs and 
other substances, frequently at surfaces or in aerosols or hydrosols, determine 
their environmental impact on global climate change.  Understanding of the 
component chemical reactions, and thermal and transport processes, will not 
only promote intelligent use of the gases where that use is essential, but also 
reveal means whereby alternative, less environmentally destructive 
substances can be employed.  Surface interaction studies can provide new and 
effective means for selectively removing GHGs from process streams or 
catalyzing their conversion to innocuous substances.  Photochemical studies 
of greenhouse gases, undertaken because of environmental relevance, have 
revealed much about the reaction chemistry of isolated gases.  The complex, 
nonlinear interactions of multiple gases and phases, however, are only 
vaguely understood, despite their clear climatic importance.  The 
combination of mass and thermal transport, photochemistry, and surface 
chemistry that describes the interactions of GHGs in the atmosphere has only 
been appreciated recently.  Attention will also be given to developing reliable 
techniques for in situ sensing and quantification of GHGs and on aliquot 
monitoring in industrial process streams.  New methods are needed for 
economical on-line sensing that would allow more careful monitoring, and 
permit tighter standards for air quality.  Fundamental chemistries underlying 
passive and active sensor design, allowing selective, specific, sensitive, and 
rapid determination of the gases requires significant development.  For those 
circumstances where sensors are inappropriate, development of next-
generation separations technologies to allow identification and quantification 
will be supported.
STAKEHOLDERS:  Projects supported under the GGD program component 
are largely laboratory-based, and will complement field observations and 
studies supported under other Global Change initiatives in Global 
Tropospheric Chemistry and remote sensing.  The GGD program will 
contribute to both short-and long-term improvement of local and global 
habitats.  The chemical manufacturing and agricultural industries, both 
major contributors to U.S. exports, would be most immediately affected by the 
introduction of new methods and criteria for process monitoring.  
Atmospheric scientists and modelers of global climate change will benefit 
from high precision baseline data and improved understanding of kinetically 
coupled GHG reactions in the atmosphere and with suspended particulates.
POLICY RELEVANCE:  The knowledge gained as a result of the program 
would provide guidance to environmental policymakers in a number of 
areas in which the complexity of the natural system has obscured the most 
appropriate action.  Solutions to problems with greenhouse gases may lie in 
the reduction of atmospheric irritants and particulates, some of which may be 
more important to control than others, and whose effectiveness may vary 
with temperature and sunlight.  Future air quality legislation may be tailored 
to particular locales and specific industries which, where feasible, might be 
located at environmentally benign sites.
PROGRAM CONTACT:  Margaret Cavanaugh, Chemistry Division