41.   Decides to enforce rules issued by Clinton that go after diesel trucks and buses as a source of dirty air.

42.   Decides to enforce rather than challenge rules issued by President Clinton that go after diesel trucks and buses as a source of dirty air.

43.   Researchers said unusually dry weather played a part in trapping dirty air over Houston, and Los Angeles may very well reclaim the title in the future.

44.   Researchers said unusually dry weather played a part in trapping dirty air over Houston, and Los Angeles may very well reclaim the title.

45.   The EPA says the tougher standards are needed to protect people with respiratory ailments, the elderly and children from the adverse health effects of dirty air.

46.   The University of California, Los Angeles study shows that the harmful effects of dirty air can extend even into the womb, the Los Angeles Times reported Sunday.