Six Arlington residents were sentenced in federal court in Dallas last week for their roles in falsifying state emissions tests at two-state-certified inspections stations in Arlington.Documents filed in the case state that at two inspection stations, Mike’s Autocare on North Mesquite Street and Tommy Tech on Peach Street, the defendants performed 7,656 fraudulent emissions tests between August 2009 and March 2011, according to the U.S. attorney’s office for the Northern District of Texas.The defendants circumvented the required emissions tests by substituting vehicles that would pass the test in place of ones that had failed or showed equipment malfunction.“Everyone has a right to breathe clean air, free from excessive vehicle emissions,” Ivan Vikin, special agent in charge of the Environmental Protection Agency’s criminal enforcement program in Texas, said in a statement. “This is one of the largest vehicle emission fraud cases in the country and is an excellent example of government agencies working together to protect both the public and the environment.”Nghiem Van Tran, 54, and Nghi Cong Tran, 32, pleaded guilty to one count of conspiracy to violate the Clean Air Act and were sentenced to 15 months in federal prison. Nghiem Van Tran was also ordered to pay a $5,000 fine.Ngan Tien Tran, 29, pleaded guilty to one count of making a false statement and was sentenced to a year in prison.Dahn Cong Tran, 26; Bich Dong Ngo, 26; and Huy Ngoc Nguyen, 26, were sentenced to a year of probation for making a false statement. Danh Cong Tran’s probation includes eight months of home confinement.The defendants generated fraudulent emissions certificates and transmitted false results to the state. The would demand up to $80 for each false test, well above the typical $39.75 that is paid for a legitimate vehicle inspection.