A system designed to improve air quality on board the Royal Navy’s nuclear submarines could be used on board airliners to counter real – and perceived – problems.

An MOD-sponsored programme led to the Submarine Atmospheres Group at QinetiQ’s Haslar Marine Technology Park looking into the performance of a photocatalytic system which involves shining ultraviolet light on to a surface coated with titanium dioxide.

This produces free radicals, which attack molecules of contaminated compounds in the air, including those which cause odours.

These are broken down into simple, harmless substances, usually water and carbon dioxide.

The free radicals have the additional benefit of killing bacteria, viruses and spores.

The use of such technology at sea in surface ships was a natural follow-up – most smells are controllable with good ventilation, although galley odours tended to be the most widespread.

Current technology uses filters, electrostatic precipitators or activated carbon beds, but all have drawbacks, either requiring regular cleaning or replacement of components, or there are dangers of clogging or even spontaneous combustion, in the case of the carbon filters.

The benefits for a closed environment such as a nuclear submarine are obvious – the system is cheap, low-powered, lightweight, easily maintained and has few or no consumable components which require changing, although it is likely to be most effective when used in conjunction with electrostatic precipitators in galley filter systems.

With fears of sickness and bugs spread in aircraft and by air travel – particularly in the wake of the SARS virus outbreaks in the Far East and Canada – photocatalytic
systems would appear to be ideally suited to airliners.

The technique does not require a high airflow, so there is usually no need for additional fans or blowers.

An airline could easily sterilise the air that is circulated through the cabin – thus allaying the fears of passengers that they are breathing in the germs of someone elsewhere on the plane.

Air bled into the cabin from engine compressors can sometimes be contaminated by high temperature lubricant, which could also be neutralised by the system.

Other potential applications for photocatalysis plants could include train toilets, or around sewage and waste treatment facilities.

This research work is being carried out by the Environmental Sciences and Services Business Group at Haslar.