President Barack Obama wants government workers to play a greener role by cutting business travel and reducing the use of cars for commuting.

The White House is expected to announce Tuesday that the government will aim to reduce carbon dioxide and other greenhouse gas emissions from indirect sources by 13 percent in 2020, compared with 2008 levels.

Earlier this year Obama directed agencies to reduce pollution from direct sources, such as buildings and government fleets, by 28 percent.

The White House says the federal government is the largest energy consumer in the U.S. economy, and the combined reductions would be the equivalent of removing emissions from 235 million barrels of oil.

Employee travel and commuting account for the biggest category of what the White House calls indirect sources of pollution.

©2010 The Associated Press. All rights reserved.