Profile: Atomospheric research

As an atmospheric chemist, Ally Lewis has spent many frustrating hours fixing kit in extreme environments. Now, as professor of atmospheric chemistry at the University of York and director for composition research at the UK’s National Centre for Atmospheric Science, he has fewer opportunities to get into the field but still gets his hands dirty when he can. When I talk to him he is preparing for a research trip to Canada with the Natural Environment Research Council’s (Nerc’s) BAE-146 research aircraft. Once a year he also visits a York-led research observatory in Cape Verde, an African island off Senegal.

’When I started as a post doc I was spending half of the year doing field experiments. I now spend about four weeks away - a luxury. I wouldn’t want it to be any less than that,’ he says.

Immense distances 

Lewis studied chemistry at the University of Leeds, then did a PhD on airborne urban particulates. Since then his work has focused on the transport and transformation of organic pollutants over immense distances. ’When I started to get projects of my own as a lecturer we did some measurements in really interesting locations, from Tasmania to the Azores and the Arctic,’ he recalls. Lewis met his wife - Lucy Carpenter, now a professor of atmospheric chemistry at York - on a field trip on the west coast of Ireland. ’A lot of atmospheric chemists meet their husbands or wives on field trips,’ laughs Lewis. 

Every trip brings a different set of practical challenges. When Lewis and his team were working on an Arctic project in Hudson Bay, Canada, the polar bears who unexpectedly arrived on the scene were the least of their worries. ’It was about -40?C and we discovered that our cables were frozen and wouldn’t uncoil. Meanwhile, the generators still contained remnants of British biofuel, which basically turned into margarine,’ he recalls. The lab equipment has a habit of breaking down in the most awkward places, often because of water in the atmosphere. ’Wherever you go you discover a new problem with water, particularly if you go to the Tropics,’ he adds.  

Diverse skills 

The field teams have a diverse range of skills, which come together to solve the technical - often electrical -problems. ’It is amazing what you can solve between you when you have no alternative - there is no technical support when you are out in the field,’ he says. ’So far we have never come across a field work problem that we couldn’t fix,’ he adds (touching wood).  

When Lewis recruits a PhD student, he checks that they know what they are letting themselves in for. ’We need people to do something that is totally different to their degree,’ he says. 

His team dedicates much time and effort to developing instruments for fieldwork. He is keen to transfer atmospheric chemistry’s tools to other areas, and currently works with the Ministry of Defence to use lab-on-a-chip sensors for defence screening.  

Lewis wants to unite atmospheric chemistry and climate research. ’One deals with reactions that have relatively short timescales, while the other deals with processes over very long periods. The next challenge is to design experiments that work on the right sort of timescale to test climate hypotheses,’ he says. This will be a difficult task, most likely requiring a different funding approach and a move away from two-year grants. Lewis already spends one and a half days a week working for Nerc, helping to direct one of its research programmes. 

He considers himself very lucky to have been involved in atmospheric chemistry since its burgeoning days in the early 1990s. ’Atmospheric chemistry in the UK is now very, very strong,’ says Lewis, with its success largely down to a high level of collaboration.

Emma Davies is a science writer based in Bishop’s Stortford, UK