Clean Air Technologies Tenneco's lightweight clean air technologies help to reduce fuel consumption, which drives CO2 emissions reduction. Mixing Technologies. Tenneco's custom-engineered mixing components ensure consistent performance of liquid urea selective catalytic reduction (SCR) aftertreatment in diesel engine exhaust systems. The company will debut its latest family of mixing solutions designed to support SCR-coated diesel particulate filter (SDPF) applications, where SCR catalyst and particulate filtration is combined into one component, responding to the need for lightweight, compact packaging of the vehicle's aftertreatment system. Tenneco's mixing technologies also support real driving emissions standards and serve as enablers for current and future emissions regulations. Gasoline Particulate Filter.