Flight paths to save the world: Aircraft routes offer hope for ozone layer

FLIGHT PATHS for aircraft could in future be routed to avoid certain altitudes and latitudes in order to preserve the atmosphere's protective ozone layer, scientists said yesterday.

The expected growth in the number of commercial flights is causing alarm among environmental scientists concerned about the damage aircraft emissions at high altitudes can do to the ozone layer. Nitrogen oxides from aircraft exhausts, for instance, are estimated to be up to 30 times more damaging to the ozone layer when released into the upper atmosphere.

Atmospheric scientists at the Natural Environment Research Council are developing a computerised prediction system to assess the best routes to fly in order to minimise ozone destruction by avoiding areas where emissions can do most damage.

John Pyle, head of the project, said he can imagine a time when air-traffic controllers include information about atmospheric chemistry in addition to weather forecasts when drawing up flight paths. 'The kind of computer models we are developing can, I think, be pushed in the future to provide that kind of information,' he said.

The instructions to aircraft pilots may be to fly a little higher or a little lower, or take a slightly different route to the north or south, he said.

A U-2 spy aircraft converted for scientific research has already taken part in a flight from New Zealand to Antarctica to test whether the NERC's computer predictions of atmospheric chemistry are accurate. They are, Dr Pyle said.

One critical prediction is to estimate the height of the invisible boundary between the lower troposphere and upper stratosphere. Dr Pyle said that emissions released into the stratosphere are potentially far more damaging.

John Woods, director of atmospheric sciences at the NERC, said future legislation - similiar to the Montreal Protocol to phase out the use of ozone-destroying aerosols - may attempt to limit the damage done by aircraft emissions to the ozone layer.