Pollution over Arctic is declining Tighter controls in Europe cited

June 01, 1993|By New York Times News Service

Atmospheric pollution over the Arctic, long a subject of environmental concern, has declined steadily and sharply in the last decade, federal scientists have found.

The decrease in the smoglike haze is apparently linked to sharp reductions in pollution emissions in Europe and the former Soviet Union, scientists at the National Oceanic and Atmospheric Administration say in a new report. The haze has diminished by about half during March and April, its worst months, since a peak in the early 1980s.

First noted by atmospheric chemists in the late 1970s, the haze turned out to be mainly a brew of sulfate particles and sulfuric acid droplets, both of which form when the pollutant gas sulfur dioxide reacts with sunlight and atmospheric moisture.

All the early signs suggested that the haze had been increasing in depth and intensity for years, and some analysts worried that its ability to absorb solar heat might lead to a rise in Arctic temperatures that could help worsen global warming.

The new study, to be published this month in Geophysical Research Letters, does not eliminate those concerns. But it suggests that the potential warming threat posed by the Arctic haze may now be "roughly half" of that once feared, said Dr. Barry Bodhaine, a research meteorologist at the federal agency who was an author of the study.

The problem appears to have improved both because the Soviet Union switched much of its fuel consumption from coal and oil to cleaner-burning natural gas throughout the 1980s, and because western European nations clamped down on sulfur dioxide emissions to reduce acid rain. The measures appear to have reduced sulfur dioxide emissions by 25 percent in Europe, including the former Soviet lands west of the Urals.

The new study relied on two independent monitoring methods at an observatory in Barrow, Alaska. One instrument, called a nephelometer, collected small samples of air about 30 feet above ground. The other instrument, called a pyrheliometer, measured the amount of sunlight reaching the ground.

Pollution-monitoring aircraft that crisscrossed the Arctic in the 1980s found that the haze was quite evenly distributed, and that measurements at Barrow generally applied to conditions regionwide.

Dr. Leonard Barrie, a senior research scientist at the Atmospheric Environment Service of Canada, said the findings at Barrow were a signal that abating air pollution in industrial areas could improve air quality thousands of miles away.

Although his measurements of the haze and other Arctic pollution problems taken on Ellesmere Island, west of northern Greenland, have not shown as much improvement in the haze as the readings at the Barrow site, he speculated that this was because of statistical "noise" in his data caused by severe weather variations in mountains to the south.

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