At long last, the Environmental Protection Agency is ready to approve the eight-hour ozone State Implementation Plan (SIP) for the Dallas-Fort Worth region. Adopted by the Texas Commission on Environmental Quality (TCEQ) in May 2007, the SIP predicts attainment of the 85-parts-per-billion ozone standard by 2010.

This is an aggressive SIP – with many costly regulatory controls on major and minor point sources of ozone precursors, and hundreds of millions in state funded grants for engine replacement or retrofit. EPA usually has allowed about five years to attain a new standard. With this new standard, EPA imposed an unrealistic time frame of only 2-1/2 years, forcing TCEQ to regulate further stationary sources (e.g., industrial facilities) when the dominant ozone driver in D-FW is mobile source (e.g., cars).

Environmentalist naysayers and opportunistic politicians decry the supposed weakness of the SIP and allege poor air quality in D-FW. Quite the contrary! As measured by multiple monitors, ozone levels are steadily improving in the Metroplex. Against all odds, D-FW actually achieved the previous one-hour standard in 2005. Without any of the onerous controls in this SIP, models show that the area would achieve the eight-hour standard by 2012 as a result of vehicle fleet turnover – new engines produce far less ozone emissions, and a growing economy accelerates the rate of new vehicle purchase. Prosperity and not regulation would most help D-FW air quality.

The federal government has exclusive authority to set engine standards. For the growing urban areas of Texas to attain ever stricter air quality standards, EPA must not merely wield authority over the state to mandate attainment; it must assume its responsibility to address mobile sources.

The environmentalists’ usual strategy to sue EPA for approving the state’s plan will do nothing but delay implementation of the SIP. TCEQ and D-FW local governments should be congratulated for successful completion of this ambitious SIP.

– Kathleen Hartnett White