The Environmental Protection Agency notified officials in 211 counties in 25 states that their air did not meet the agency's strengthened standards for levels of fine particles.
The PM 2.5 standard, as it's called, restricts the amount of airborne fine particles with a diameter smaller than 2.5 micrometers, or about one-thirtieth the diameter of a human hair. These particles, such as those emitted by power plants, livestock operations, diesel engines, and wood-burning stoves, are thought to be associated with poor health.
In 2006, the agency tightened the standards from 65 micrograms per cubic meter of air to 35 micrograms per cubic meter. If the levels of these fine particles in a given area exceed that figure for more than 24 hours, the area is considered not in compliance.
According to the Associated Press, the stricter standards mean that 15 new metro areas got failing marks. The EPA's list of too-sooty counties, which are home 100 million Americans, now includes 46 cities.
States with areas that fall below the EPA's standards will have three years to develop plans for improving air quality, or risk fines. From there, the areas will have another two years to meet the standards.
“These designations are an important step in our steady march toward cleaner air,” said EPA Administrator Stephen L. Johnson in a press release. “We will continue working with our state and tribal partners to meet these air quality standards.”
The press release noted that, nationwide, monitored levels of fine particle pollution dropped 11 percent from 2000 to 2007.
Critics argue, however, that even though the air is getting less sooty, the EPA's enforcement is still too lax.
The PM 2.5 standard is actually only one of two standards for airborne particulates. Additionally, an area must not exceed an average annual concentration of 15 micrograms per cubic meter. But, as the Associated Press reports, the EPA is not citing cities that violate this annual standard:
Because of that, at least five regions, including Houston, that did violate the yearly soot standards, don't have to do anything about it and residents are not told there's a problem, said Frank O'Donnell, president of the environmental group Clean Air Watch.
"EPA has failed to protect many millions of people from deadly particle soot by pretending that areas are clean where the air is actually dirty," O'Donnell said. "The poster child for this is Houston."
"It is a very bad holiday gift to breathers in cities like Houston," O'Donnell said. "The Bush administration has given them the gift of dirty air."
The other areas left off the EPA's list, but still violating annual standards, include Augusta and Columbus, Ga.; Greenville, S.C., and Fairmont, W.Va., O'Donnell said.