Adding a creative twist to academia/industry collaboration, scientists have persuaded businessman Richard Branson to take one of their experiments up in his hot air balloon, which was due to begin its round-the-world expedition tow-ards the end of this week.

When environmental scientists from the University of East Anglia heard about Mr Branson's trip, they realised what an opportunity it could provide for increasing their knowledge about the atmosphere. The scientists, who study the depletion of ozone, normally have to send up unmanned balloons, which rise up - but then come straight down, giving only a snapshot of the vertical structure of the air. Manned balloons are expensive, and aircraft cannot stay up very long.

But Mr Branson will be floating high, at about 35,000 feet, and staying up there for as long as it takes him to circumnavigate the globe.

The balloon team realised that it could make a unique contribution to study of ozone depletion because, as Bill Sturges, senior research associate in UEA's school of environmental sciences, said, "they will be following one piece of air and can see how it evolves over time".

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"Virgin seemed to be extremely receptive to the idea," says Dr Sturges. So he and his colleagues Stuart Penkett and Trevor Davies hastily built some equipment: a pair of compressors that will pump air in from outside the travellers' capsule, pressurise it and put it into flasks - one a day for 24 days.

Dr Sturges said that the pumping would require a "certain degree of competence" but that the complicated work would be after the balloon returns, when the scientists will analyse the air samples on their powerful gas chromatograph mass spectrometer, which can measure up to 40 different halocarbons - the ozone-eaters - at concentrations equivalent to one molecule in a thousand trillion.

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The balloon will travel in the sub-tropical jet stream, about 22-30 degrees north. The study may help clarify whether this area is the gateway through which air enters the stratosphere, after which it goes on to damage ozone. The equipment weighs 16 kg and Dr Sturges has one main worry: "We hope they won't use it as ballast."