Sars wars

The spread of dangerous diseases such as Sars on international flights could be prevented by an air purification technology being developed in the UK. Airbus said this week that it is considering a photocatalysis system that uses ultraviolet light to remove viruses, bacteria and odours from the air.

A spokeswoman for Airbus said the company is involved in European research projects looking into photocatalysis technology, and has been working with US-based air filtration specialist Pall. ‘Pall is working with Qinetiq on the technology,’ she said.

Although Sars appears to have peaked, new deaths were reported in Canada and Taiwan this week, and health officials are calling for extra vigilance to contain future outbreaks. The sight of terrified passengers wearing face masks on flights to avoid the threat of Sars has brought into sharp relief the danger global air travel poses to the spread of disease, said David Howells, business development manager at Qinetiq, which is also in discussions with Boeing and a number of airlines.

‘Since the recent Sars scare there has been a renewed interest in air purification for aircraft. UV light has a sterilising nature, and we believe it would be effective against bacteria and viral agents. We are looking to prove its level of effectiveness against agents like Sars,’ he said.

The system is based on a surface coated in titanium dioxide. Ultraviolet light is applied to the surface, releasing highly energetic free radicals – atoms with an unpaired electron – which attack contaminating molecules in the air, breaking them down into harmless substances such as water and carbon dioxide.

‘The system acts like a huge sponge, and the free radicals are so energetic they can remove all the elements. It could form the basis of an environmental control system, to purify the whole cabin interior,’ he said.

The device is highly sensitive, and can be used to kill bacteria, viruses and spores. ‘It can take out elements down to parts of a billion, it has a very high knock-out rate and is very effective for a whole range of species,’ said Howells.

As well as bacteria and viruses, the system could also remove nasty smells from areas such as the galley and toilets, which can be unpleasant for passengers, particularly on long-haul flights.

The researchers have built a prototype device, and are now hoping to form a partnership with an aircraft supplier to develop the system. A stand-alone device for use within aircraft toilets and galleys could be produced within around one year, but developing a larger system that would be capable of handling the airflow for the entire aircraft will take slightly longer, he said.

‘The demonstrator has fairly low volumes of air running through it, so we will inevitably need to address issues involved in scaling up the system,’ said Howells.

Qinetiq is developing the UV technology following research into the treatment of air aboard nuclear submarines for the Ministry of Defence.

Photocatalysis could be used to break down most of the contaminants that build up in the atmosphere of a submarine during prolonged diving periods, particularly organic compounds such as those from lubricants and oils.

However, existing systems are bulky and rely on activated carbon beds, which require frequent replacement.