Automobile Club of Southern California Progress in Vehicle Exhaust Emission Control

A study of 93 new 1972 vehicles of various makes and models was made to determine what effect the more stringent California emission standards have had on exhaust emission levels (especially oxides of nitrogen), fuel economy, and engine design. Data are compared with similar fleets of 1970 and 1971 model vehicles and show an encouraging reduction in exhaust emission levels, with a penalty in fuel economy.