The U.S. Environmental Protection Agency will early next week, possibly as soon as Monday, officially declare carbon dioxide a public danger, a trigger that could mean regulation for emitters across the economy, according to several people close to the matter. Such an “endangerment” decision is necessary for the EPA to move ahead early next year with new emission standards for cars. The announcement would also give President Barack Obama and his climate envoy negotiating leverage at a global climate summit starting next week in Copenhagen, Denmark and increase pressure on Congress to pass a climate bill that would modify the price of polluting.