Research Team Produces First Global Inventory Of Reactive Chlorine
Emissions To The Atmosphere
23, 1999 -- An international team of atmospheric
chemists has produced the first gridded global inventory of reactive
chlorine emissions to the atmosphere. Reactive chlorines are of
interest because some of these compounds contribute to the destruction
of stratospheric ozone, some are toxic to humans at high-dose exposures,
and others are carcinogenic at chronic, lower-dose exposures.
collaborative study involved 20 researchers from academia, government
and industry working in six countries over three years. The research
was conducted under the auspices of the International Global Atmospheric
Chemistry Programme's Global Emissions Inventory Activity. Results
were published in a seven-article special section of the April 20,
1999, issue of the Journal of Geophysical Research.
work provides an objective benchmark for assessing our current understanding
of the global chlorine cycle and for investigating the potential
environmental implications of future changes in chlorine emissions,"
says William C. Keene, research associate professor of environmental
sciences at the University of Virginia. "The inventory should
facilitate informed public policy decisions for the regulation of
was a principal investigator for the project and served as a lead
organizer, manager and director for the planning and execution of
the study. The project is similar to the global carbon emissions
inventory conducted several years ago to investigate natural and
human influences on the atmospheric carbon quantity. That benchmark
study was central to the discussions leading to the recent Kyoto
Protocols, a set of international guidelines for regulating future
anticipate that the chlorine emissions study may be employed in
a similar manner," Keene says, "although our results are associated
with greater uncertainty because multiple compounds are involved
and the underlying observational data are more limited."
working groups characterized emissions of 10 specific chlorine-containing
compounds from each of four different classes of source types: oceanic
and terrestrial biogenic emissions; sea-salt production and dechlorination;
biomass burning; and exclusively human-made emissions from industrial
sources and coal burning. Emissions of those compounds for which
sufficient information was available were gridded over the earths
surface on a one-degree by one-degree scale. The individual inventories
for each compound were then integrated across source types and the
relative importance of natural and human-caused sources differentiated.
The result is a set of "known" inventories of specific chlorine-containing
compounds as a function of source type that can be applied in various
types of further investigations.
anticipate that these results will provide critical input data for
future modeling studies, as well as a useful perspective in planning
future measurement programs," Keene says in the preface to the seven
papers published in the journal.
financial support for the project was provided by the Chemical Manufacturers
Association via the Chlorine Chemistry Council and from the European
Chemical Industry via Euro Chlor (a federation of the European chlorine
industry). Individual investigators also received support from other
agencies and institutions, including the U.S. National Science Foundation
and the Atmospheric Environment Service, Canada.
more information about this study, see the website for the Reactive
Chlorine Emissions Inventory at: http://blueskies.sprl.umich.edu/geia/rcei.
Fariss Samarrai, (804) 924-3778.