On Air: Houston is an initiative of the Greater Houston Partnership to share accurate information about the air we breathe in Houston. Houston is experiencing robust economic growth. From 2011 to 2012, the metro area’s real GDP grew 5.3 percent to $449.4 billion, making it the fourth largest metro economy in the U.S. (most recent estimate from the U.S. Bureau of Economic Analysis). Due to the combined efforts of all of us—business and industry, local, state and federal government, and individual citizens—our region has been able to maintain that level of economic growth while achieving substantial air quality improvements in the past 20 years. The Partnership believes it is critical to share that story.