Patent on trading of sufur dioxide emissions

United States Patent 7,734,531 is entitled “Method for promoting sulfur dioxide futures trading.” The inventors are listed as Richard Sandor of Chicago, IL and Michael Walsh of Downers Grove, IL. The patent contains process claims, device claims, and system claims relating to futures contracts for sulfur dioxide trading.  Each of the claims are at least “related” to sulfur dioxide.  The face of the patent indicates that is was assigned to Chicago Climate Exchange, Inc. also of Chicago, IL.