Clean Air Test Only is a smog test place located in the same area as a Valero gas station and convenient store. Clean Air does smog testing but not repair for non-passing vehicles. If your car passes, Clean Air will take care of the paperwork to the DMV. It has a list of recommendations in case a car doesn't pass a smog check and offer a list of problems on why the car didn't pass. Cars can return to Clean Air to do a re-test.