In the late 1980s, Roger Sheldon developed the concept of the E Factor and the EQ (Environmental Quotient) for assessing the waste generation and environmental impact of chemical manufacturing processes, highlighting the pressing need for cleaner catalytic processes to replace classical 'stoichiometric' technologies in the fine chemical and pharmaceutical industries. His E Factor concept was subsequently accepted worldwide and many companies now use it for assessing the potential environmental impact of their processes. 

Now, fifteen years on Sheldon has reviewed the effect that the E Factor concept has had on developments in the fine chemical and pharmaceutical industry in a perspective published in Issue 12 of Green Chemistry. He looks at its impact on waste minimisation and assesses its current status in the broader context of green chemistry and sustainability. Sheldon concludes that the E Factor concept has played a major role in focusing the attention of the chemical industry world-wide, and particularly the pharmaceutical industry. 'It has provided, and continues to provide, the impetus for developing cleaner, more sustainable processes,' he said. 

The publication of the perspective is timely, as 2007 marks the 65th birthday of Roger Sheldon and his retirement from the Chair of Biocatalysis and Organic Chemistry at the Delft University of Technology. A farewell symposium in his honour is being held in Delft on the 6th and 7th December to mark the occasion. 

Roger Sheldon was the founding Chair of the Green Chemistry Editorial Board in 1998 and has continued to support the journal over the past 10 years. We would like to take this opportunity to thank him for his support and wish him well in his retirement. 

"We were delighted that our final issue of 2007 featured a perspective by Roger Sheldon, the founding Chair of our Editorial Board. He set a tradition of rigour and excellence which we are determined to continue," said Martyn Poliakoff, current Chair of the Green Chemistry Editorial Board.