The Chicago Tribune reports, in a major boost to Midwest corn growers, the Environmental Protection Agency mandated yesterday the continued year-round use of oxygen additives, such as corn-based ethanol, in polluted cities, rejecting a California proposal to use clean-burning gasoline without such additives. By the end of next year, California will be in the market for 550 million gallons of ethanol annually, about a third of what’s produced this year. The increased demand for ethanol will be so great that there are questions about whether farmers and producers can make enough. The triumph of ethanol demonstrates anew the political muscle of an industry that donated more than $1.6 million to federal politicians in 1999 and 2000, more than half of which came from Decatur-based Archer Daniels Midland, the nation’s largest ethanol producer. It’s an industry that government subsidizes generously. Tax breaks for ethanol in Illinois cost $60 million a year, while federal ethanol subsidies this year will total $900 million.