Johnson Matthey uses a Life Cycle Assessment tool to understand the environmental impact of producing a catalytic converter for a diesel powered car


It takes raw materials and energy to make a catalytic converter for a car but at what point do the environmental benefits of a catalyst outweigh the environmental costs of producing it? A Johnson Matthey team embarked on an analysis to understand and better quantify the sustainability benefits of one of its environmental technologies.

The background to the study lay in Johnson Matthey's wish to understand the impact of its products all along the value chain, from sourcing the raw materials to the long term use by the end consumer. Customers and other stakeholders are already interested in the life cycle of our products – a trend that we believe will only grow in the future – and the lessons we learn can be fed into developing the next generation of environmental products.

The tool chosen was quantitative Life Cycle Assessment (LCA), which allows the impact of a product to be traced during its whole life. A life cycle experts group was formed, made up of 12 people from across Johnson Matthey's businesses. The team then selected one of the company's core products – a catalytic converter for a diesel powered car – for analysis.

We worked with an international consultancy and used a methodology drawn from ISO standards 14040 and 14044. The 'cradle to grave' analysis covered the full life cycle of the product, from the extraction of raw materials (which included primary platinum) to disposal at end of life. A range of impact categories were studied to understand the positive and negative effects the product has on land, air and water. These impact categories included the use of non-carbon based resources and energy, global warming potential, emissions that cause acid rain, eutrophication or deplete ozone and emissions of precursors that contribute to low level smog.

The product is made up of two separate catalysts, one manufactured at our operations in South Africa and containing virgin platinum group metals (pgms), the other produced in the UK using recycled pgms from a Johnson Matthey refinery. The catalysts are then sent to a third party in mainland Europe for assembly into an exhaust pipe. All transportation impacts were taken into account.

So what were the findings? The study was highly insightful and informative and generated several key learning points for the company. The product itself is designed to clean up pollutants which contribute to the formation of low level smog and it was clear that in this impact category, the environmental positives strongly outweighed the negatives. An environmental breakeven point was calculated, showing that after the vehicle had been driven 1,000km, the negative impacts from production were cancelled out by the positives, as the product cleaned up the exhaust gas and reduced the level of pollutants that contribute to low level smog.

Another key finding was that using recycled pgms is kinder to the environment by several orders of magnitude across all impact categories. Activities in the supply chain were found to constitute more than half of the environmental impact of the catalytic converter and shipping products by sea between continents didn't add significantly to the environmental footprint.

The company is a world leader in catalysts and about a third of all cars around the world are fitted with a Johnson Matthey catalytic converter. With the help of the LCA tools, Johnson Matthey aims to better understand the environmental and health benefits of other key products in its portfolio and to develop new technologies with enhanced sustainability benefits in the future.