A heavy reddish haze is a regular feature of the Arctic in winter and early spring, often reducing visibility to less than 6 miles (about 10 kilometres). A haze so far from the industries and vehicles that pollute the air of major cities seems to require a wholly natural explanation, but evidence has begun to accumulate that a part of the arctic haze may have its origins 6,000 miles (10,000 kilometres) away in the same polluted air that produces acid rain over the USA and Europe. According to a study undertaken in 1976, it would seem that, due to air flow patterns and other factors, the major source of the pollutants in the arctic haze is the Soviet Union. Europe and England are the next largest sources of the pollution. North American countries contribute little because of air flow patterns.
Air pollution threatens an area of the Arctic equal in size to the North American continent, jeopardizing the fragile Arctic ecosystem. Pollutants are carries north by dry air masses from industrial areas, and in winter there is no precipitation to remove them from the atmosphere. Increasing pollution may affect not only Arctic life forms, but also global climate patterns. The pollution extends from Alaska eastward to Norway - about half of the circumference of the polar ice cap - and is suspended from ground level to as high as 25,000 feet from November through April.