Obituary: Professor Alan Wellburn

ALAN WELLBURN was a biochemist who made numerous contributions to our understanding of the ways in which plants function in different environments, particularly in atmospheres contaminated with air pollutants. He was an early authority on "acid rain" and climate change.

He gained a first class honours degree at Liverpool in 1963, followed by a PhD in 1966, and in the autumn of that year became Assistant Lecturer in Plant Biochemistry at the fledgling Lancaster University, two years after it was founded. He remained there for the rest of his career, becoming a professor in 1989.

His early research was on chloroplast development, a process that is essential before a young plant can carry out photosynthesis and begin to manufacture new materials for growth. It was his special understanding of these events that pointed him to an interest that became dominant in recent years. Up to 1970 there was little understanding of the impacts of air pollutants on cellular processes in plants or animals, and his discovery in 1972 of the damage to chloroplasts caused by air pollution was seminal.

He showed that combinations of sulphur dioxide and nitrogen dioxide, two pollutants produced by burning coal or oil, could cause serious damage to the delicate internal structure of chloroplasts. Soon he developed an explanation of why these two pollutants together can be much more toxic than when they are alone, leading to a reappraisal of the safe limits of exposure for crops and natural communities.

This work was completed some years before the dangers of acid rain were widely appreciated, and Wellburn became a leading authority on it. His book Air Pollution and Acid Rain: the biological impact (1988) covered the complex chemical issues with such clarity that it became a much used text for research workers and students. In the 1990s environmental concerns drifted away from acid rain to the enhanced "greenhouse effect", and the book was extensively revised and published as Air Pollution and Climate Change (1994).

Wellburn enjoyed many profitable collaborations, and he had joint publications with prominent scientists in his field who worked for short periods in his laboratory in Lancaster. He took sabbaticals in Australia, and Germany, where he had the distinction of being an Alexander von Humboldt Fellow. His longest and most productive scientific collaboration was, however, with his wife Florence and there are many well-known "Wellburn & Wellburn" papers in the literature.

In the 1980s a young German scientist, Horst Mehlhorn, came to Lancaster and his collaboration with Alan Wellburn led to significant advances in understanding the damage to plants caused by ozone pollution. Their publications challenged some entrenched opinions, and marked the beginning of a period of intensive research into ozone and its impacts upon which Alan was working with Florence up to the time of his death.

Alan Wellburn had many interests outside science, and he served his local community in Lunesdale as chairman of the parish council in Leck, as a churchwarden, and as a school governor. He was Chairman of the Lunesdale Civic Society, and in 1997 he published a booklet, Leck, Cowan Bridge and the Brontes, to coincide with a "Bronte Pilgrimage" which involved walking the route from the Clergy Daughters' School in Cowan Bridge (Charlotte Bronte's "Lowood" in Jane Eyre) to Tunstall Church for Matins, to Leck for Evensong, and back to Cowan Bridge.

Alan Richard Wellburn, plant biochemist: born Scarborough, Yorkshire 30 August 1940; Assistant Lecturer, Lancaster University 1966-68, Lecturer 1968-77, Senior Lecturer 1977-89, Professor 1989-99; married 1966 Florence Brown (one son, one daughter); died Lancaster 8 May 1999.