If you've entered a Wawa convenience store recently, you may have seen green signs posted on the doors warning of potential $3,000 fines for leaving diesel cars or trucks idling for longer than 3 minutes, according to a story in the Burlington County Times newspaper. Turns out the signs are as much for Wawa's protection as they are for yours, since business owners are also subject to fines if motorists violate the state's air pollution laws on their property. Vincentown Diner owner Jimmy Melissarato learned that lesson the hard way earlier this month when a state Department of Environmental Protection inspector issued his business a $200 citation. The inspector had caught a trucker running a rig in the diner parking lot on Route 38 in Southampton for 20 minutes. State environmental officials say the inspections are necessary to improve air quality and protect public health. They admit it is no coincidence that the green signs began popping up at Wawa stores about the same time the department began a statewide enforcement sweep to catch and punish polluters. The enforcement action began Aug. 9 and is ongoing, said Erin Phalon, spokeswoman for the state DEP. It is only directed against diesel-powered motor vehicles, she said. As of press time, 115 vehicles had been cited in New Jersey. State administrative code says diesel-powered vehicles may idle for no more than 3 minutes unless located at their home base of operation, where they may run for up to 30 minutes. Phalon said the rule has been a part of the state's administrative code for several years, but this month's sweep is the first organized enforcement action. She said inspectors visited areas where residents have complained about idling vehicles as well as locations where trucks and buses typically park. These include convenience stores, warehouses, large parking lots, bus depots and industrial parks. Non-commercial drivers are subject to fines ranging from $100 for the first offense to $1,500 for the fourth violation. Commercial drivers and the property owners where the violations occur face stiffer fines - from $200 for the first offense to as much as $3,000 for the fourth.