The Houston-Galveston-Brazoria (HGB) area holds nonattainment status for ground-level ozone under the 1997 8-hour standard which became effective June 15, 2005. Counties affected under this status are Brazoria, Chambers, Fort Bend, Galveston, Harris, Liberty, Montgomery, and Waller. The region was classified as being in " moderate" nonattainment of the 8-hour standard and was given a maximum attainment date of June 15, 2010. However, due to a 2007 request by Texas Governor Rick Perry, the region has been reclassified as a "severe" nonattainment region with a maximum attainment date of June 15, 2019. The state environmental agency, Texas Commission on Environmental Quality (TCEQ), has additional information relating to the history and status of the HGB area. See http://www.tceq.state.tx.us/implementation/air/sip/texas-sip/hgb/sip-hgb for more information.
For the Houston-Galveston-Brazoria region the process of creating and approving a list of mobile source control strategies