View the CleanAIR PERMIT Filter at work as it reduces diesel emissions of particulate matter by greater than 85%, and reduces hydrocarbons and carbon monoxide by up to 99% on off-road diesel vehicles. The PERMIT Filter is individually customized for each application and can be designed as a filter/muffler emissions control system taking the place of a standard muffler. Diesel retrofits using particulate filters can substantially reduce toxic air pollution emissions at a construction site or mining facility.