R C E I Mission Statement

The use of chlorine and chlorine-containing compounds by industry and in water purification is the focus of considerable debate and possible regulatory action by the U.S., Canadian, and European governments. Proposed regulatory strategies have substantial implications for many segments of the world economy including water purification, the manufacture of paper, solvents, plastics, pharmaceuticals and other chemicals, and industries that rely on these products. Large uncertainties in our understanding of the natural biogeochemistry of chlorine confound critical assessment of the potential environmental impact of anthropogenic influences. Natural reservoirs and processes are important and often dominant components of the aquatic, marine, and tropospheric chlorine budgets. Although there is much experimental information concerning natural and anthropogenic emissions of reactive chlorine, it had not been synthesized and analyzed to produce an integrated assessment of the global atmospheric chlorine cycle or the role of natural emissions.

This GEIA project developed a global emissions inventory for the major reactive chlorine species in the troposphere. Principal objectives were: 1) To develop and verify individual global emissions inventories on a 1° x 1° grid scale for particulate Cl^-, HCl, other inorganic Cl gases, CH₃Cl, CH₃CCl₃, CCl₂=CCl₂, CHCl=CCl₂, CH₂Cl₂, CHCl₃, and HCFCs; 2) To develop and verify a composite, multi-species inventory on a 1° x 1° grid scale by integrating the individual inventories; and 3) To critically assess overall uncertainties for each inventory.

This research effort was conducted under the auspices of the International Global Atmospheric Chemistry (IGAC) Program's Global Emissions Inventory Activity (GEIA); the work involved investigators from several institutions and countries each with expertise in specific fields. Results yielded the first integrated estimates for gridded emissions fluxes of reactive chlorine on a global scale. The inventory allows quantitative differentiation of the relative magnitudes and associated environmental significance of major natural and anthropogenic sources. As part of the analysis, we critically assessed the reliability of the estimates and thereby constrained overall uncertainties in the emission fluxes of reactive chlorinated compounds. Results provide important and previously unavailable information with which to make informed decisions regarding proposed regulatory strategies.

If you would like to join future RCEI activities, please contact the convenor William C. Keene.

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3-Mar-2001