A downloadable timeline illustrating the progress of catalytic converters in vehicles. In 2014, one out of every three cars in the world is fitted with a Johnson Matthey autocatalyst, which removes over 99% of the engine's dangerous emissions. This means the gases that leave your vehicle are virtually as clean as the air that enters, and many millions of tonnes of pollutants are prevented from entering the atmosphere. This poster charts our pathway from smog in UK cities during the 1950s to catalytic converters in the present day.