Animation showing the CleanAIR PERMIT Filter/Silencer reducing back-up generator emissions using PERMIT diesel particulate filters. The PERMIT Filter is CARB verified - Level 3, for emergency and prime power stationary diesel engines to reduce particulate matter by greater than 85 percent. It also reduces hydrocarbons and carbon monoxide by up to 99 percent. The CleanAIR PERMIT Filter/Silencer with the CleanAIR HiBACK Data Logger and Alarm System is a complete air pollution control system for stationary generators.