Johnson Matthey Plc engages in the manufacture of measuring devices. It operates through the following segments: Clean Air, Efficient Natural Resources, Other Markets, and Corporate. The Clean Air segment focuses on catalysts and catalyst systems to reduce emissions from vehicles and industry. The Efficient Natural Resources segment creates value from efficient use and transformation of critical natural resources including oil, gas, biomass, and platinum group metals. The company was founded by Percival Norton Johnson in 1817 and is headquartered in London, the United Kingdom.