"The park's air violates the federal ozone and fine-particle standards, prompting health warnings to hikers."
http://www.charlotte.com/171/story/729436.html
"The park's air violates the federal ozone and fine-particle standards, prompting health warnings to hikers."
http://www.charlotte.com/171/story/729436.html
http://www.weather.gov/aq/
Pick a state. Check the time. Some states are clickable, on a number station.