For most people, concerned action about the hole in the ozone layer stops at buying hairspray free of chlorofluorocarbons.

But since last November, Weld Professor of Atmospheric Chemistry James G. Anderson has trekked back and forth between Cambridge and Bangor, Maine.

There Anderson is mission scientist at the Arctic Airborne Stratosphere Experiment, which is collecting data on the chemical composition of the ozone layer.

To obtain this data, six pilots fly single-engine, single-jet ER-2 planes into subzero temperature zones.

Among the dangers they face flying at such low temperatures is hypothermia, which has been known to result in pilots' losing control of their planes.

"They're a pretty courageous group of people," says Anderson.

Bangor was chosen as the planes' home base because it is in a good position for collecting data from mid to low latitudes.

Anderson began researching ozone in 1970, and he created his first instruments to measure chemicals in the ozone layer in 1974. When NASA needed a mission scientist, he was the logical person to call.

"As mission scientist I spend a great deal of time analyzing data, planning the next mission, worrying about the weather, and talking to the pilots," Anderson says.

The intrument Anderson created for the ER-2s use lasers to detect molecules as the air flows through it. Because ER-2 aircraft do not have command communication with the ground, information is stored by an on board computer and is analyzed after the plane lands.

"Experimenters exchange data and come to preliminary conclusions within hours of the landing," says Larry B. Lapson, an 11-year veteran of the project.

"This is quite unusual in the scientific community," Lapson says. "Usually information is chewed over for months."

The ozone hole is caused by a high concentration of chlorine radicals eating away at the atmosphere. Anderson's group is studying the weakening of the ozone layer in the low to middle latitudes, where, he says, there has been "a general sagging" of the atmosphere.

The research team expects an additional hole to develop in this area within the decade.

Anderson says he finds one of the most fascinating aspects of the project to be its social and political importance. The international protocol developed after the discovery of the ozone hole has provided a paradigm for all future scientific studies, he says.