The federal government said the Phoenix area's air violated a clean-air standard because of unhealthy levels of dust, an expected step that gives Arizona until the end of the year to adopt a plan that could impose new mandates on builders, farmers and drivers. "The clock is ticking," said Steve Owens, the state's top environmental regulator. High levels of the particles pose a health threat because they affect the respiratory system and can damage lung tissue and cause premature death.
(Los Angeles Times, 16/03/2007)