Local officials must reduce smog by June 2009, the Environmental Protection Agency said Thursday after increased testing found unacceptable air quality in parts of Maricopa and Pinal counties.
The counties were among 474 nationwide that didn’t meet eight-hour monitoring standards for ground-level ozone, a precursor to smog. The designation forces officials to develop a plan to meet the tougher standards after nearly eight years of complying with previous one-hour monitoring rules.
Under the new regulations, pollutants in the Valley’s air have measured slightly worse than the standard.
Although the variation is small, population growth will make meeting the standard a challenge, authorities said.
Air monitoring officials will pay closer attention to nitrogen oxides, which come primarily from vehicles.
Measures to reduce nitrogen oxide levels could include changes to vehicle emissions testing, transportation planning and older combustion systems at industrial facilities and power plants.
For Arizona, the EPA’s announcement also included finalized boundaries in which tougher smog standards must be met. The EPA set the boundaries within both Maricopa and the area within Pinal County that includes Apache Junction.