Catalyst technology from Johnson Matthey has, over the last 30 years, contributed to an amazing reduction in the emissions from passenger cars (see chart). For the last 10 years, JM’s CRT^® system has been used to remove the particulate matter from the exhaust of city buses, further improving the quality of urban air and improving the environment for city dwellers. Catalysts are used to clean gas streams from many industrial processes. Now, catalytic exhaust aftertreatment is being used on heavy duty diesel vehicles and on engines, large and small, in non-road applications.