US EPA
http://www.epa.gov/ozonedesignations/2008standards/final/finaldes.htm
[Transportation Nation] [EPA's] latest data, released Tuesday, found that forty-five areas of the country fail to meet air quality standards for ground level ozone. The standards were set by the Bush Administration in 2008. They allow 75 parts of smog per billion cubic feet of air. As you can see on the map below, pockets of the country in almost all regions fail to meet air quality standards, but the bulk of “nonattainment” areas are along the Northeast corridor and throughout California.
