A Valley air activist group today announced it will file suit aimed at forcing the state to honor diesel pollution reduction promises.

The Association of Irritated Residents said the California Air Resources Board is not fulfilling a commitment to reduce tons of diesel pollution by 2010. The board's landmark rule for diesel reductions will not produce results quickly enough, the group said.

The letter sent to the state says the suit would be filed about Oct. 22 in federal court. Another social justice organization, Communities for a Better Environment, also would be a plaintiff. The group is based both in Northern and Southern California.