"WASHINGTON, DC -- Forty-five areas across the country are not meeting the latest government standards for ground-level ozone or smog, the U.S. Environmental Protection Agency said Tuesday."
"In 2008, EPA set a new smog standard at 75 parts per billion measured over eight hours, tightening the standard from the 80 parts per billion set in 1997.
'Reflecting ongoing improvements in air quality,' EPA says it is identifying fewer areas that do not meet the 2008 standards than the agency identified as failing to meet the 1997 standards.
Following a change in standards, EPA works with states and tribes to identify areas that fail to meet the standards and establish plans to improve air quality.
Smog is created when emissions from vehicles, power plants, refineries and other factories mix in the presence of sunlight and heat. "