The EPA says recent progress made in decreasing smog has stalled: The amount of smog over the USA failed to decline during the past decade despite a nationwide effort to improve air quality, statistics from the Environmental Protection Agency show. Smog levels dropped during the 1980s. But the latest edition of the EPA’s annual report on air quality shows that smog levels didn’t get better from 1993 through 2002. Independent scientists have drawn similar conclusions. Not to be too much of a glass-if-half-full kind of guy, but with the increase in population and vehicle miles, holding the line against smog is no small feat. Meanwhile, roughly 20 years after it’s been available officials in Southern California are finally turning to remote sensing to reduce pollution: The sensor, an infrared beam that changes color if pollutant levels are too high, could snag vehicles that passed their last smog checks but fell out of compliance before their next check is up. Smog checks, which cost about $50, are required every two years. “If a vehicle develops a problem and starts to become a high emitter, you don’t necessarily have to wait two years until the problem is fixed,” said Sam Atwood, a spokesman for the South Coast Air Quality Management District. Officials in California and Colorado have tested the sensors before, but Atwood said he believed the planned rollout in parts of Los Angeles, Orange, Riverside and San Bernardino counties would be the most widespread use in the nation. No firm start date has been set, but the board’s vote called for the sensors to be in place by a 2010 federal deadline. The proposal was added at the AQMD’s request to a broader plan approved by the California Air Resources Board, which is designed to cut more than 1,200 tons a day of smog-creating pollutants throughout Southern California. The sensors would eliminate an estimated 16 tons a day, Atwood said.