Their innovation, reported this week in Science, is based on desorption electrospray ionisation (DESI), an analytical technique which can be deployed in the field.

ECONOMIST: Forensic technology

The report said the hospital had made an "investment in measures to control legionella" including the introduction of a silver and copper ionisation disinfection system, to replace its chlorine dioxide one.

BBC: 'Legionella concerns' remain at Basildon hospital

The compounds in their breath were analysed using a technique called secondary electrospray ionisation mass spectrometry (SESI-MS), which is capable of detecting extremely small elements of the chemicals present in their breath.

BBC: Lung infection identified using 'breath-print'